JP5277038B2 - Force detection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simplify a structure, eliminate the interference of a component of other axis, and to detect a force and a moment separately. <P>SOLUTION: Electrodes E1 to E8 and F1 to F8 are formed in four circular areas, at positive and negative positions on an X-axis and positive and negative positions on a Y-axis on a support substrate 300. On the upper parts of the circular areas respectively, electrically conductive and flexible thin disks are arranged at prescribed distances provided to form capacity elements between facing electrodes and the electrodes. The lower end of a post shaped member is fixed at the center of an upper surface of each of the thin disks. To the upper end of each post-shaped member, a force-receiving member is attached. When a force is applied to the force-receiving member, the four post shaped members are inclined or vertically displaced to change electrostatic capacity values of the capacity elements, respectively. Based on the change in the electrostatic capacity values of the main capacity elements formed by the electrodes E1 to E8, forces Fx, Fy and Fz in the directions of coordinate axes and moments Mx, My and Mz on coordinate axes respectively are detected. At this time, based on the change of the electrostatic capacity values of sub-capacity elements formed by the electrodes F1 to F8, interference of components of other axes is canceled. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a force detection device, and more particularly, to a force detection device suitable for detecting force and moment independently.

  Various types of force detection devices are used to control the operation of robots and industrial machines. Also, a small force detection device is incorporated as a man-machine interface of an input device of an electronic device. In order to reduce the size and reduce the cost, the force detection device used for such an application has a simple structure as much as possible and can independently detect forces related to each coordinate axis in a three-dimensional space. Is required.

  In general, the detection target of the force detection device includes a force component directed in a predetermined coordinate axis direction and a moment component around the predetermined coordinate axis. When the XYZ three-dimensional coordinate system is defined in the three-dimensional space, the detection target is six components including force components Fx, Fy, Fz in the respective coordinate axis directions and moment components Mx, My, Mz around the respective coordinate axes. .

  As a force detection device capable of detecting each of these six force components independently, for example, Patent Document 1 below discloses a device having a relatively simple structure. The technique disclosed in Patent Document 1 is a technique to which US Pat. No. 6,915,709, US Pat. No. 7,121,147, and European Patent No. 1464939 are already provided, and a force receiving body and a support substrate are provided with a plurality of columnar bodies. The components connected in the above are prepared, and each component of the force applied to the force receiving body is detected by individually measuring the pressing force applied to the support substrate from each columnar body and the inclination of each columnar body.

  The technique disclosed in Patent Document 2 below is also a technique to which US Pat. No. 7,219,561 has already been granted. According to this technology, a capacitive element is used as a sensor for individually measuring the pressing force applied to the support substrate from each columnar body and the inclination of each columnar body, and wiring is performed between specific electrodes constituting this capacitive element. By applying the above, it is possible to simplify the calculation for detecting each component of the force applied to the force receiving body.

  On the other hand, Patent Document 3 below discloses a technique for detecting six force components independently using only eight capacitive elements. According to this technology, it is possible to further simplify the electrode structure necessary for forming the capacitive element.

JP 2004-354049 A JP 2004-325367 A JP 2008-096229 A

  As described above, the force detection devices disclosed in Patent Documents 1 to 3 have force components Fx, Fy, and Fz in the coordinate axis directions and moment components Mx, My, and Mz around the coordinate axes with a relatively simple structure. 6 components can be detected independently of each other. However, in practice, it is difficult to obtain accurate measurement values of only the necessary components with the interference of other axis components completely eliminated, and a decrease in measurement accuracy due to interference of other axis components is inevitable. . Of course, there is no problem as long as the interference of other axis components is within an allowable error range according to each application, but recently, a force detection device with higher measurement accuracy is desired in various fields of use. It is rare.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a force detection device that has a simple structure as much as possible, eliminates interference of other axis components, and can detect force and moment separately.

(1) A first aspect of the present invention includes a support substrate, a force receiving body disposed above the support substrate, and four columnar bodies for connecting the support substrate and the power receiving body. In a state where the support substrate is fixed, a force detection device that detects the force acting on the force receiving body,
Each upper end of the four columnar bodies is connected to a force receiving body via a flexible member, and each lower end of the four columnar bodies has a flexible lower end side thin wall. Are connected,
The lower end side thin portion is connected to the support substrate via a pedestal so that the lower end side thin portion is arranged in parallel to the upper surface of the support substrate at an upper position with a predetermined distance from the upper surface of the support substrate. The part is connected to the lower end of the columnar body,
The XY plane is positioned on or above the upper surface of the support substrate so as to be parallel to the upper surface of the support substrate. Thus, when the XYZ three-dimensional coordinate system is defined,
The four columnar bodies are arranged so that their central axes are parallel to the Z axis, and the first columnar body is arranged at a position where the central axis intersects the positive part of the X axis. The second columnar body is disposed at a position where the central axis intersects the negative portion of the X axis, and the third columnar body is disposed at a position where the central axis intersects the positive portion of the Y axis. The fourth columnar body is disposed at a position where the central axis intersects the negative part of the Y axis,
One electrode is formed on the lower surface of the lower end thin portion, and the other electrode is the upper surface of the support substrate in a space sandwiched between the lower end thin portion of the first columnar body and the upper surface of the support substrate facing the first columnar body. A first sensor comprising a plurality of capacitive elements formed in
One electrode is formed on the lower surface of the lower end thin portion, and the other electrode is the upper surface of the support substrate in a space sandwiched between the lower end thin portion of the second columnar body and the upper surface of the support substrate facing the second columnar body. A second sensor comprising a plurality of capacitive elements formed in
One electrode is formed on the lower surface of the lower end thin portion, and the other electrode is the upper surface of the support substrate in a space sandwiched between the lower end thin portion of the third columnar body and the upper surface of the support substrate facing the third columnar body. A third sensor comprising a plurality of capacitive elements formed in
One electrode is formed on the lower surface of the lower end thin portion and the other electrode is the upper surface of the support substrate in a space sandwiched between the lower end thin portion of the fourth columnar body and the upper surface of the support substrate facing the fourth columnar body. A fourth sensor composed of a plurality of capacitive elements formed in
The first sensor has a first main capacitive element located in the first quadrant of the XY coordinate system, and a second main capacitive element located in the fourth quadrant of the XY coordinate system,
The second sensor has a third main capacitive element located in the second quadrant of the XY coordinate system, and a fourth main capacitive element located in the third quadrant of the XY coordinate system,
The third sensor has a second sub-capacitance element and a fourth sub-capacitance element,
The fourth sensor has a first sub-capacitance element and a third sub-capacitance element,
A detection circuit for detecting a predetermined direction component of the force acting on the force receiving body based on the capacitance value of each capacitive element;
When the moment Mx around the X axis acts on the force receiving body, the absolute value of the change in the capacitance value generated in the first main capacitive element and the change in the capacitance value generated in the first sub-capacitance element The absolute value of the change in the capacitance value generated in the second main capacitive element is equal to the absolute value of the change in the capacitance value generated in the second sub-capacitance element. Thus, the absolute value of the change in the capacitance value generated in the third main capacitance element is equal to the absolute value of the change in the capacitance value generated in the third subcapacitance element, and the fourth main capacitance. Each capacitive element is configured such that the absolute value of the change in capacitance value occurring in the element is equal to the absolute value of the change in capacitance value occurring in the fourth subcapacitance element,
The detection circuit is configured such that the capacitance value of the first main capacitance element is C1, the capacitance value of the first subcapacitance element is D1, the capacitance value of the second main capacitance element is C2, and the second sub capacitance element is C2. The capacitance value of the capacitance element is D2, the capacitance value of the third main capacitance element is C3, the capacitance value of the third sub-capacitance element is D3, and the capacitance value of the fourth main capacitance element is C4, when the capacitance value of the fourth sub-capacitance element is D4, the Y-axis direction component Fy of the force acting on the force receiving member is
Fy = (C1 + D1) − (C2 + D2) + (C3 + D3) − (C4 + D4)
This is obtained using the following arithmetic expression.

(2) According to a second aspect of the present invention, in the force detection device according to the first aspect described above,
The detection circuit further detects a moment component My around the Y axis of the force acting on the power receiving body.
My = (C1 + D1) + (C2 + D2)-(C3 + D3)-(C4 + D4)
This is obtained using the following arithmetic expression.

(3) According to a third aspect of the present invention, in the force detection device according to the first or second aspect described above,
The detection circuit further includes a Z-axis direction component Fz of the force acting on the power receiving body,
Fz = − ((C1 + D1) + (C2 + D2) + (C3 + D3) + (C4 + D4))
This is obtained using the following arithmetic expression.

(4) According to a fourth aspect of the present invention, in the force detection device according to the first to third aspects described above,
Wiring for connecting the first main capacitive element and the first sub-capacitor in parallel with each other; wiring for connecting the second main capacitive element and the second sub-capacitor in parallel with each other; Wiring for connecting the third main capacitive element and the third sub-capacitor in parallel with each other; wiring for connecting the fourth main capacitive element and the fourth sub-capacitor in parallel with each other; Further provided,
The detection circuit uses, as the value of “C1 + D1”, the capacitance value of the combined capacitance element configured by parallel connection of the first main capacitance element and the first subcapacitance element, and the second main capacitance element and the first The capacitance value of the composite capacitance element configured by parallel connection with the second sub-capacitance element is used as the value of “C2 + D2”, and is configured by parallel connection of the third main capacitance element and the third sub-capacitance element. Is used as the value of “C3 + D3”, and the capacitance value of the composite capacitive element configured by parallel connection of the fourth main capacitive element and the fourth sub-capacitance element is “C4 + D4”. "Is used as the value of". "

(5) According to a fifth aspect of the present invention, in the force detection device according to the first to fourth aspects described above,
Each lower end side thin portion is made of a conductive material, and the lower end side thin portion itself functions as a common electrode for a plurality of capacitive elements constituting the same sensor.

(6) According to a sixth aspect of the present invention, in the force detection device according to the fifth aspect described above,
The four electrodes on the support substrate side constituting the first to fourth main capacitive elements are constituted by electrodes having the same shape and the same size, and these four electrode arrangement patterns are represented by an XZ plane and a YZ. Both planes are symmetrical with respect to the plane.

(7) According to a seventh aspect of the present invention, there is provided a support substrate, a force receiving body disposed above the support substrate, and four columnar bodies for connecting the support substrate and the power receiving body. In a state where the support substrate is fixed, a force detection device that detects the force acting on the force receiving body,
Each upper end of the four columnar bodies is connected to a force receiving body via a flexible member, and each lower end of the four columnar bodies has a flexible lower end side thin wall. Are connected,
The lower end side thin portion is connected to the support substrate via a pedestal so that the lower end side thin portion is arranged in parallel to the upper surface of the support substrate at an upper position with a predetermined distance from the upper surface of the support substrate. The part is connected to the lower end of the columnar body,
The XY plane is positioned on or above the upper surface of the support substrate so as to be parallel to the upper surface of the support substrate. Thus, when the XYZ three-dimensional coordinate system is defined,
The four columnar bodies are arranged so that their central axes are parallel to the Z axis, and the first columnar body is arranged at a position where the central axis intersects the positive part of the X axis. The second columnar body is disposed at a position where the central axis intersects the negative portion of the X axis, and the third columnar body is disposed at a position where the central axis intersects the positive portion of the Y axis. The fourth columnar body is disposed at a position where the central axis intersects the negative part of the Y axis,
One electrode is formed on the lower surface of the lower end thin portion, and the other electrode is the upper surface of the support substrate in a space sandwiched between the lower end thin portion of the first columnar body and the upper surface of the support substrate facing the first columnar body. A first sensor comprising a plurality of capacitive elements formed in
One electrode is formed on the lower surface of the lower end thin portion, and the other electrode is the upper surface of the support substrate in a space sandwiched between the lower end thin portion of the second columnar body and the upper surface of the support substrate facing the second columnar body. A second sensor comprising a plurality of capacitive elements formed in
One electrode is formed on the lower surface of the lower end thin portion, and the other electrode is the upper surface of the support substrate in a space sandwiched between the lower end thin portion of the third columnar body and the upper surface of the support substrate facing the third columnar body. A third sensor comprising a plurality of capacitive elements formed in
One electrode is formed on the lower surface of the lower end thin portion and the other electrode is the upper surface of the support substrate in a space sandwiched between the lower end thin portion of the fourth columnar body and the upper surface of the support substrate facing the fourth columnar body. A fourth sensor composed of a plurality of capacitive elements formed in
The first sensor includes a first main capacitive element located in the first quadrant of the XY coordinate system, a second main capacitive element located in the fourth quadrant of the XY coordinate system, and a sixth sub-capacitive element. An eighth sub-capacitor element,
The second sensor includes a third main capacitive element located in the second quadrant of the XY coordinate system, a fourth main capacitive element located in the third quadrant of the XY coordinate system, and a fifth sub-capacitive element. A seventh sub-capacitor element,
The third sensor includes a fifth main capacitive element located in the first quadrant of the XY coordinate system, a sixth main capacitive element located in the second quadrant of the XY coordinate system, and a second sub-capacitive element. A fourth sub-capacitor element,
The fourth sensor includes a seventh main capacitive element located in the fourth quadrant of the XY coordinate system, an eighth main capacitive element located in the third quadrant of the XY coordinate system, and a first sub-capacitive element, A third sub-capacitor element,
A detection circuit for detecting a predetermined direction component of the force acting on the force receiving body based on the capacitance value of each capacitive element;
When the moment Mx around the X axis acts on the force receiving body, the absolute value of the change in the capacitance value generated in the first main capacitive element and the change in the capacitance value generated in the first sub-capacitance element The absolute value of the change in the capacitance value generated in the second main capacitive element is equal to the absolute value of the change in the capacitance value generated in the second sub-capacitance element. Thus, the absolute value of the change in the capacitance value generated in the third main capacitance element is equal to the absolute value of the change in the capacitance value generated in the third subcapacitance element, and the fourth main capacitance. The absolute value of the change in capacitance value occurring in the element is equal to the absolute value of the change in capacitance value occurring in the fourth sub-capacitance element,
When the moment My around the Y axis acts on the force receiving member, the absolute value of the change in the capacitance value generated in the fifth main capacitive element and the change in the capacitance value generated in the fifth sub-capacitance element The absolute value of the change in the capacitance value generated in the sixth main capacitive element is equal to the absolute value of the change in the capacitance value generated in the sixth sub-capacitance element. Thus, the absolute value of the change in the capacitance value generated in the seventh main capacitance element is equal to the absolute value of the change in the capacitance value generated in the seventh subcapacitance element, and the eighth main capacitance. Each capacitive element is configured such that the absolute value of the change in capacitance value occurring in the element is equal to the absolute value of the change in capacitance value occurring in the eighth subcapacitance element,
The detection circuit is configured such that the capacitance value of the first main capacitance element is C1, the capacitance value of the first subcapacitance element is D1, the capacitance value of the second main capacitance element is C2, and the second sub capacitance element is C2. The capacitance value of the capacitance element is D2, the capacitance value of the third main capacitance element is C3, the capacitance value of the third sub-capacitance element is D3, and the capacitance value of the fourth main capacitance element is C4, the capacitance value of the fourth sub-capacitance element is D4, the capacitance value of the fifth main capacitance element is C5, the capacitance value of the fifth sub-capacitance element is D5, and the sixth main capacitance element , The capacitance value of the sixth sub-capacitance element is D6, the capacitance value of the seventh main capacitance element is C7, the capacitance value of the seventh sub-capacitance element is D7, When the capacitance value of the eighth main capacitance element is C8 and the capacitance value of the eighth sub capacitance element is D8,
The Y-axis direction component Fy of the force acting on the force receiving body is
Fy = (C1 + D1) − (C2 + D2) + (C3 + D3) − (C4 + D4)
Using an arithmetic expression
The X-axis direction component Fx of the force acting on the force receiving body is
Fx = (C5 + D5)-(C6 + D6) + (C7 + D7)-(C8 + D8)
This is obtained using the following arithmetic expression.

(8) According to an eighth aspect of the present invention, in the force detection device according to the seventh aspect described above,
The detection circuit further detects a moment component My around the Y axis of the force acting on the power receiving body.
My = (C1 + D1) + (C2 + D2)-(C3 + D3)-(C4 + D4)
The moment component Mx around the X axis of the force acting on the force receiving body is calculated using the following equation:
Mx = − (C5 + D5) − (C6 + D6) + (C7 + D7) + (C8 + D8)
This is obtained using the following arithmetic expression.

(9) According to a ninth aspect of the present invention, in the force detection device according to the seventh or eighth aspect described above,
The detection circuit further includes a Z-axis direction component Fz of the force acting on the power receiving body,
Fz = − ((C1 + D1) + (C2 + D2) + (C3 + D3) + (C4 + D4) + (C5 + D5) + (C6 + D6) + (C7 + D7) + (C8 + D8))
This is obtained using the following arithmetic expression.

(10) According to a tenth aspect of the present invention, in the force detection device according to the seventh to ninth aspects described above,
The detection circuit further detects a moment component Mz around the Z-axis of the force acting on the power receiving body.
Mz = (C1 + D1)-(C2 + D2)-(C3 + D3) + (C4 + D4)-(C5 + D5) + (C6 + D6) + (C7 + D7)-(C8 + D8)
This is obtained using the following arithmetic expression.

(11) An eleventh aspect of the present invention is the force detection device according to the seventh to tenth aspects described above,
Wiring for connecting the first main capacitive element and the first sub-capacitor in parallel with each other; wiring for connecting the second main capacitive element and the second sub-capacitor in parallel with each other; Wiring for connecting the third main capacitive element and the third sub-capacitor in parallel with each other; wiring for connecting the fourth main capacitive element and the fourth sub-capacitor in parallel with each other; Wiring for connecting the fifth main capacitive element and the fifth sub-capacitor in parallel with each other; wiring for connecting the sixth main capacitive element and the sixth sub-capacitor in parallel with each other; Wiring for connecting the seventh main capacitance element and the seventh subcapacitance element in parallel with each other; wiring for connecting the eighth main capacitance element and the eighth subcapacitance element in parallel with each other; Further provided,
The detection circuit uses, as the value of “C1 + D1”, the capacitance value of the combined capacitance element configured by parallel connection of the first main capacitance element and the first subcapacitance element, and the second main capacitance element and the first The capacitance value of the composite capacitance element configured by parallel connection with the second sub-capacitance element is used as the value of “C2 + D2”, and is configured by parallel connection of the third main capacitance element and the third sub-capacitance element. Is used as the value of “C3 + D3”, and the capacitance value of the composite capacitive element configured by parallel connection of the fourth main capacitive element and the fourth sub-capacitance element is “C4 + D4”. As the value of “C5 + D5”, and the capacitance value of the combined capacitive element constituted by the parallel connection of the fifth main capacitive element and the fifth sub-capacitor element is used as the sixth main capacitive element. And the sixth sub-capacitor in parallel connection The capacitance value of the combined capacitance element formed is used as the value of “C6 + D6”, and the capacitance value of the combined capacitance element configured by parallel connection of the seventh main capacitance element and the seventh subcapacitance element is This is used as the value of “C7 + D7”, and the capacitance value of the composite capacitive element formed by parallel connection of the eighth main capacitive element and the eighth sub-capacitance element is used as the value of “C8 + D8”. is there.

(12) A twelfth aspect of the present invention is the force detection device according to the seventh to eleventh aspects described above,
The four columnar bodies are constituted by structures of the same shape and the same size, and the arrangement pattern of the four columnar bodies is symmetrical with respect to both the XZ plane and the YZ plane. It is a thing.

(13) According to a thirteenth aspect of the present invention, in the force detection device according to the twelfth aspect described above,
Each lower end side thin portion is made of a conductive material, and the lower end side thin portion itself functions as a common electrode for a plurality of capacitive elements constituting the same sensor.

(14) According to a fourteenth aspect of the present invention, in the force detection device according to the thirteenth aspect described above,
The eight electrodes on the support substrate side constituting the first to eighth main capacitive elements are constituted by electrodes of the same shape and the same size, and the arrangement pattern of these eight electrodes is an XZ plane and The plane is symmetrical with respect to both YZ planes.

(15) According to a fifteenth aspect of the present invention, in the force detection device according to the fourteenth aspect described above,
The two electrodes on the support substrate side constituting the first and second main capacitive elements cut the first annular band disposed around the central axis of the first columnar body along the X axis. Composed of two electrodes obtained by
The two electrodes on the support substrate side constituting the third and fourth main capacitive elements cut the second annular band disposed around the central axis of the second columnar body along the X axis. Composed of two electrodes obtained by
Two electrodes on the support substrate side constituting the fifth and sixth main capacitive elements cut the third annular band arranged around the central axis of the third columnar body along the Y axis. Composed of two electrodes obtained by
The four electrodes on the support substrate side constituting the seventh and eighth main capacitive elements cut the fourth annular band arranged around the central axis of the fourth columnar body along the Y axis. Composed of two electrodes obtained by
Two electrodes on the support substrate side constituting the sixth and eighth sub-capacitance elements are arranged in an inner region surrounded by the first annular band,
Two electrodes on the support substrate side constituting the fifth and seventh sub-capacitance elements are arranged in an inner region surrounded by the second annular band,
Two electrodes on the support substrate side constituting the second and fourth sub-capacitance elements are arranged in an inner region surrounded by the third annular band,
Two electrodes on the support substrate side constituting the first and third sub-capacitance elements are arranged in the inner region surrounded by the fourth annular band.

(16) According to a sixteenth aspect of the present invention, in the force detection device according to the fifteenth aspect described above,
Each columnar body is made of a cylindrical structure, each thin portion on the lower end side is made of a disk-like structure, and each annular band is made of an annular structure.

(17) According to a seventeenth aspect of the present invention, in the force detection device according to the sixteenth aspect described above,
Of the two electrodes on the support substrate side constituting the sixth and eighth sub-capacitance elements, one is constituted by an electrode having an annular shape, and the other is constituted by an electrode disposed in the inner region thereof,
Of the two electrodes on the support substrate side constituting the fifth and seventh sub-capacitance elements, one is constituted by an electrode having an annular shape, and the other is constituted by an electrode arranged in the inner region thereof,
Of the two electrodes on the support substrate side constituting the second and fourth sub-capacitance elements, one is constituted by an electrode having an annular shape, and the other is constituted by an electrode arranged in the inner region thereof,
Of the two electrodes on the support substrate side constituting the first and third sub-capacitance elements, one is constituted by an electrode having an annular shape, and the other is constituted by an electrode disposed in the inner region. It is what I did.

(18) According to an eighteenth aspect of the present invention, in the force detection device according to the sixteenth aspect described above,
2 obtained by cutting, along the X-axis, a disk in which two electrodes on the support substrate side constituting the sixth and eighth sub-capacitance elements are arranged around the central axis of the first columnar body. Composed of a semicircular electrode,
2 obtained by cutting, along the X-axis, a disk in which two electrodes on the support substrate side constituting the fifth and seventh sub-capacitance elements are arranged around the central axis of the second columnar body. Composed of a semicircular electrode,
2 obtained by cutting, along the Y-axis, a disk in which two electrodes on the support substrate side constituting the second and fourth sub-capacitance elements are arranged around the central axis of the third columnar body. Composed of a semicircular electrode,
2 obtained by cutting, along the Y-axis, a disk in which two electrodes on the support substrate side constituting the first and third sub-capacitance elements are arranged around the central axis of the fourth columnar body. It is configured by a single semicircular electrode.

(19) According to a nineteenth aspect of the present invention, in the force detection device according to the sixteenth aspect described above,
Reference is made to a disk in which the two electrodes on the supporting substrate side constituting the sixth and eighth sub-capacitance elements are arranged around the central axis of the first columnar body, passing through the central point and parallel to the Y axis It is composed of two semicircular electrodes obtained by cutting along the axis,
Reference is made to a disk in which the two electrodes on the support substrate side constituting the fifth and seventh sub-capacitance elements are arranged around the central axis of the second columnar body, passing through the central point and parallel to the Y axis It is composed of two semicircular electrodes obtained by cutting along the axis,
Reference is made to a disk in which the two electrodes on the support substrate side constituting the second and fourth sub-capacitance elements are arranged around the central axis of the third columnar body, passing through the central point and parallel to the X axis It is composed of two semicircular electrodes obtained by cutting along the axis,
Reference is made to a disk in which the two electrodes on the support substrate side constituting the first and third sub-capacitance elements are arranged around the central axis of the fourth columnar body, passing through the central point and parallel to the X axis It is configured by two semicircular electrodes obtained by cutting along the axis.

(20) According to a twentieth aspect of the present invention, in the force detection device according to the fourteenth to sixteenth aspects described above,
Both the two electrodes on the support substrate side constituting the sixth and eighth sub-capacitance elements are both related to the reference plane including the central axis of the first columnar body and parallel to the YZ plane, and the XZ plane. A shape that is plane symmetric,
Both the two electrodes on the support substrate side constituting the fifth and seventh sub-capacitance elements are both related to the reference plane including the central axis of the second columnar body and parallel to the YZ plane, and the XZ plane. A shape that is plane symmetric,
Both the two electrodes on the support substrate side constituting the second and fourth sub-capacitance elements are both related to the reference plane including the central axis of the third columnar body and parallel to the XZ plane, and the YZ plane. A shape that is plane symmetric,
Both the two electrodes on the support substrate side constituting the first and third sub-capacitance elements are both related to the reference plane including the central axis of the fourth columnar body and parallel to the XZ plane, and the YZ plane. The shape is symmetrical with respect to the plane.

(21) According to a twenty-first aspect of the present invention, in the force detection device according to the fourteenth to sixteenth aspects described above,
Each of the two electrodes on the support substrate side constituting the sixth and eighth sub-capacitance elements has a shape that is plane-symmetric with respect to a reference plane that includes the central axis of the first columnar body and is parallel to the YZ plane. ,
Each of the two electrodes on the support substrate side constituting the fifth and seventh sub-capacitance elements has a shape that is plane-symmetric with respect to a reference plane that includes the central axis of the second columnar body and is parallel to the YZ plane. ,
Each of the two electrodes on the support substrate side constituting the second and fourth sub-capacitance elements has a shape that is plane-symmetric with respect to a reference plane that includes the central axis of the third columnar body and is parallel to the XZ plane. ,
Both of the two electrodes on the support substrate side constituting the first and third sub-capacitance elements have a shape that is plane-symmetric with respect to a reference plane that includes the central axis of the fourth columnar body and is parallel to the XZ plane. It is what I did.

(22) According to a twenty-second aspect of the present invention, in the force detection device according to the first to twenty-first aspects described above,
When the moment Mx around the X-axis or the moment My around the Y-axis acts on the force receiving body, the ratio of the area of the electrode constituting the main capacitive element to the area of the electrode constituting the sub-capacitor corresponding thereto In addition, the area ratio is set such that the absolute value of the change in capacitance value generated in the main capacitive element is equal to the absolute value of the change in capacitance value generated in the sub-capacitance element.

(23) According to a twenty-third aspect of the present invention, in the force detection device according to the first to twenty-second aspects described above,
As a flexible member for connecting each upper end of the four columnar bodies to the power receiving body, the upper end of which the periphery is connected to the power receiving body and the center of the lower surface is connected to the upper end of the columnar body A side thin part is provided.

  According to the force detection device of the present invention, the force receiving body and the support substrate are connected by the four columnar bodies, and the pressing force applied from each columnar body to the support substrate and the inclination of each columnar body are individually measured. Thus, each component of the force applied to the force receiving body can be detected, so that a detection device having a very simple structure can be realized. In addition, basically, while adopting a configuration in which each force component is independently detected using the main capacitive element, a sub-capacitance element corresponding to each main capacitive element is provided, and interference elements of other axis components are provided. Since cancellation can be performed, it is possible to eliminate the interference of other axis components and detect force and moment separately.

1 is a perspective view (partially a block diagram) showing a basic configuration of a force detection device according to the present invention. It is a front view which shows the fundamental operation | movement principle of the force detection apparatus shown in FIG. 1 is a top view of a force detection device according to a basic embodiment of the present invention. FIG. 4 is a first side sectional view of the force detection device according to the basic embodiment of the present invention, and shows a cross section obtained by cutting the device shown in FIG. 3 along the XZ plane. It is the 2nd sectional side view of the force detection apparatus which concerns on fundamental embodiment of this invention, and the cross section which cut | disconnected the apparatus shown in FIG. 3 along the YZ plane is shown. FIG. 6 is a cross-sectional view showing a state where the force receiving body 100 of the force detection device shown in FIGS. 4 and 5 is cut along the X′Y ′ plane. FIG. 7 is a cross-sectional view showing a state where the intermediate body 200 of the force detection device shown in FIGS. 4 and 5 is cut along a cutting line 7-7. FIG. 6 is a cross-sectional view illustrating a state where the intermediate body 200 of the force detection device illustrated in FIGS. 4 and 5 is cut along an XY plane. FIG. 6 is a top view of a support substrate 300 of the force detection device shown in FIGS. 4 and 5. It is XZ side sectional drawing of the force detection apparatus which concerns on practical embodiment of this invention. FIG. 11 is a side sectional view showing a deformation mode of a structure when a force + Fx in the positive direction of the X axis is applied to the force detection device shown in FIG. 10. FIG. 11 is a side sectional view showing a deformation mode of the structure when a force + Fz in the positive direction of the Z-axis acts on the force detection device shown in FIG. 10. It is a sectional side view which shows the virtual deformation | transformation aspect of a structure when the moment + My around Y-axis acts on the force detection apparatus shown in FIG. 10 is a table showing the basic detection principle of each force component using eight main capacitive elements C1 to C8 in the force detection device shown in FIG. 10, and each main component when each force component acts on a force receiving body. 14 shows a mode of change of the capacitance value of the capacitive element (the action of the moment assumes the virtual deformation mode shown in FIG. 14 and shows a mode in which no other-axis interference component is considered). It is a figure which shows the principle which detects each force component using the electrostatic capacitance value of eight main capacitive elements C1-C8 based on the table shown in FIG. 14 using a numerical formula. FIG. 16 is a graph showing measurement results in which other-axis interference occurs in the force Fy in the Y-axis direction due to the moment Mx around the X-axis when detection based on the principle shown in FIGS. 14 and 15 is performed. FIG. 14 is a table obtained by correcting the table shown in FIG. 14 in consideration of the other-axis interference component (the column enclosed by a thick line is the column to be corrected). FIG. 10 is an enlarged plan view of 16 electrodes shown in FIG. 9. In the force detection device shown in FIG. 10, it is a table showing the change of the capacitance value of each sub-capacitance element when each force component acts on the force receiving body (the column enclosed by the thick line is the sub-capacitance element) This is a column in which a change occurs in the electrostatic capacity value). Each column showing the change in capacitance value for the eight main capacitance elements C1 to C8 shown in FIG. 17, and the change in capacitance value for the eight sub capacitance elements D1 to D8 shown in FIG. Is a table showing the sum of each column (the column surrounded by a thick line is a column in which the capacitance value of the sub-capacitance element changes). The figure which shows the principle which detects each force component using an electrostatic capacitance value of eight main capacitive elements C1-C8 and eight sub-capacitance elements D1-D8 based on the table shown in FIG. It is. It is a sectional side view which shows an example of the experimental method for determining the area ratio of the electrode which comprises a main capacitive element, and the electrode which comprises a subcapacitance element. It is an enlarged plan view which shows the example of wiring with respect to 16 electrodes shown by FIG. FIG. 19 is an enlarged plan view showing a first modification of the 16 electrodes shown in FIG. 18 (the shapes and arrangement of the eight electrodes F1 to F8 constituting the sub-capacitance element are different). FIG. 25 is a table showing changes in electrostatic capacitance values of the sub-capacitance elements D1 to D8 when each force component acts on the force receiving body in the first modification shown in FIG. 24. FIG. Each column indicating the change in capacitance value for the eight main capacitance elements C1 to C8 shown in FIG. 17, and the change in capacitance value for the eight sub capacitance elements D1 to D8 shown in FIG. It is a table which shows the sum of each column which shows the aspect of this. FIG. 19 is an enlarged plan view showing a second modification of the 16 electrodes shown in FIG. 18 (the shapes and arrangement of the eight electrodes F1 to F8 constituting the sub-capacitance element are different). In the 2nd modification shown in FIG. 27, it is a table which shows the aspect of the change of the electrostatic capacitance value of each subcapacitance element D1-D8 when each force component acts on a power receiving body. Each column showing the change in capacitance value for the eight main capacitance elements C1 to C8 shown in FIG. 17, and the change in capacitance value for the eight sub capacitance elements D1 to D8 shown in FIG. It is a table which shows the sum of each column which shows the aspect of this. It is a top view explaining arrangement | positioning of the electrode F1 which comprises the subcapacitance element D1 with respect to the electrode E1 which comprises the main capacitive element C1. The top view explaining an example (example corresponding to the example of Drawing 18) of arrangement of electrodes F1 and F2 which constitute subcapacitance elements D1 and D2 to electrodes E1 and E2 which constitute main capacity elements C1 and C2 It is. Another example of the arrangement of the electrodes F1, F2 constituting the sub-capacitance elements D1, D2 with respect to the electrodes E1, E2 constituting the main capacitance elements C1, C2 (an example corresponding to the first modification of FIG. 24) FIG. Another example of the arrangement of the electrodes F1, F2 constituting the sub-capacitance elements D1, D2 with respect to the electrodes E1, E2 constituting the main capacitance elements C1, C2 (an example corresponding to the second modification of FIG. 27) FIG.

  Hereinafter, the present invention will be described based on the illustrated embodiments.

<<< §1. Basic structure of equipment >>
First, the basic structure of the force detection device according to the present invention will be described. This basic structure itself is already disclosed in Patent Documents 1 to 3 described above.

  As shown in FIG. 1, the basic components of the force detection device according to the present invention include a force receiving body 10, a first columnar body 11, a second columnar body 12, a third columnar body 13, and a fourth columnar body. 14, support substrate 20, first sensor 21, second sensor 22, third sensor 23, fourth sensor 24, and detection circuit 30.

  Here, for convenience of explanation, an XYZ three-dimensional coordinate system and an X′Y′Z ′ auxiliary coordinate system obtained by translating the coordinate system upward are defined. In the case of the illustrated example, the origin O of the XYZ three-dimensional coordinate system is defined at the center position of the upper surface of the support substrate 20, and the upper surface of the support substrate 20 is included in the XY plane. The right side of the figure is the X-axis positive direction, the diagonally back side of the figure is the Y-axis positive direction, and the upper side of the figure is the Z-axis positive direction. On the other hand, the origin O ′ of the X′Y′Z ′ auxiliary coordinate system is at a position obtained by moving the origin O by a predetermined distance in the positive direction of the Z axis. Specifically, the origin O ′ is located at the center of the force receiving body 10. Therefore, the X axis and the X ′ axis are parallel, the Y axis and the Y ′ axis are parallel, and the Z axis and the Z ′ axis overlap each other.

  The force receiving body 10 is a component that receives a force to be detected, and the force receiving body 10 has the origin O ′ of the X′Y′Z ′ auxiliary coordinate system at the center of the force receiving body 10. This is a convenience for explaining the force acting on the. In the figure, the force Fx in the X-axis direction, the force Fy in the Y-axis direction, and the force Fz in the Z-axis direction acting on the force receiving body 10 are respectively shown along the X ′ axis, the Y ′ axis, and the Z ′ axis. Of course, these forces are forces parallel to the X-axis, Y-axis, and Z-axis, respectively, and the X-axis direction component of the force applied to the force receiving member 10 is represented by the Y-axis. This indicates the direction component and the Z-axis direction component.

  As described above, the forces Fx, Fy, and Fz may be considered as forces along the coordinate axes of the X′Y′Z ′ auxiliary coordinate system or forces along the coordinate axes of the XYZ three-dimensional coordinate system. Although there is no difference in the essence as a physical quantity, the essence as a physical quantity varies depending on where the origin position of the coordinate system is taken for the moments Mx, My, and Mz. In particular, since the present invention relates to a force detection device having high measurement accuracy that eliminates interference of other axis components, here, an XYZ three-dimensional coordinate system and an X′Y′Z ′ auxiliary coordinate system are clearly defined. We will treat them separately.

  That is, the forces Fx, Fy, Fz and moments Mx, My, Mz to be detected by the force detection device according to the present invention are applied to the forces acting around the coordinate axes in the XYZ three-dimensional coordinate system and around the coordinate axes. This is why the arrows indicating the moments Mx and My are drawn around the X axis and the Y axis in FIG. 1 (the Z axis and the Z ′ axis overlap each other, so the moment Mz is Z It can be considered as a moment around the 'axis). In other words, the object to which the moments Mx and My directly act is the force receiving body 10, but these moments act to rotate the force receiving body 10 about the origin O 'at the center position. Rather than fulfilling the above, the force receiving body 10 is rotated around the origin O of the XYZ three-dimensional coordinate system.

  Eventually, this force detection device has an X-axis direction component Fx, a Y-axis direction component Fy, a Z-axis direction component Fz, and a moment component Mx around the X-axis in the XYZ three-dimensional coordinate system. , The moment component My around the Y axis and the moment component Mz around the Z axis are independently detected.

  In the present application, the term “force” is appropriately used when it means a force component in a specific coordinate axis direction and when it means a collective force including a moment component. For example, in FIG. 1, the forces Fx, Fy, and Fz mean force components in the coordinate axis directions that are not moments, but six forces Fx, Fy, Fz, Mx, My, and Mz. In this case, it means a collective force including a force component in each coordinate axis direction and a moment component around each coordinate axis.

  The support substrate 20 is a component that is disposed below the force receiving body 10 and fulfills the function of supporting the force receiving body 10. As described above, in the example shown here, the upper surface of the support substrate 20 is included in the XY plane. This force detection device detects a force acting on the force receiving body 10 in a state where the support substrate 20 is fixed.

  The first columnar body 11 to the fourth columnar body 14 are members that connect the force receiving body 10 and the support substrate 20, and are all disposed so that the central axis thereof is parallel to the Z axis. Moreover, the first columnar body 11 is arranged at a position where the central axis intersects the positive part of the X axis, and the second columnar body 12 is a position where the central axis intersects the negative part of the X axis. The third columnar body 13 is disposed at a position where its central axis intersects the positive part of the Y axis, and the fourth columnar body 14 is disposed at a position where the central axis intersects the negative part of the Y axis. It is arranged at the position to do.

  In practice, it is preferable that the first columnar body 11 to the fourth columnar body 14 have the same material, the same shape, and the same size. This is because the detection sensitivities of the first sensor 21 to the fourth sensor 24 can be made the same if these materials, shapes, and sizes are made the same. If the materials, shapes, and sizes are different from each other, it is difficult to equalize the sensitivities of the sensors, and a device for correcting the sensitivity is required. For the same reason, the shape and arrangement pattern of each columnar body are preferably plane-symmetric with respect to both the XZ plane and the YZ plane.

  Although not shown in FIG. 1, the upper ends of the respective columnar bodies 11 to 14 are connected to the force receiving body 10 through flexible members, and the respective columnar bodies 11 to 11 are connected. The lower end of 14 is connected to the support substrate 20 via a flexible connection member. In short, the first columnar body 11 to the fourth columnar body 14 are connected to the force receiving body 10 and the support substrate 20 with flexibility. Here, flexibility is synonymous with elasticity, and in a state where no force is applied to the force receiving body 10, the force receiving body 10 takes a fixed position with respect to the support substrate 20. When some force is applied to the force body 10, the flexible connecting member is elastically deformed, and the relative position between the force receiving body 10 and the support substrate 20 is changed. Of course, when the force acting on the force receiving body 10 disappears, the force receiving body 10 returns to the original fixed position.

  After all, in the case of the example shown in FIG. 1, the upper end portion and the lower end portion of the first columnar body 11 to the fourth columnar body 14 are each constituted by a flexible connecting member (of course. The whole of the first columnar body 11 to the fourth columnar body 14 may be made of a flexible material). And since this connection member produces a certain amount of elastic deformation, the 1st columnar body 11-the 4th columnar body 14 can incline with respect to the force receiving body 10 and the support substrate 20. FIG. Further, this connecting member can be expanded and contracted in the vertical direction (Z-axis direction) in the figure, and when the force receiving body 10 is moved in the upward direction (+ Z-axis direction) in the figure, the connecting member expands and contracts, The distance between the force receiving body 10 and the support substrate 20 increases. Conversely, when the force receiving body 10 is moved in the downward direction (−Z-axis direction) in the figure, the connecting member expands and contracts, and the force receiving body 10 and the support substrate 20 are expanded. The distance to will be narrowed. Of course, the degree of such displacement and inclination increases according to the magnitude of the force acting on the force receiving body 10.

  The first sensor 21 to the fourth sensor 24 detect the inclination of the first columnar body 11 to the fourth columnar body 14, respectively, and support substrates from the first columnar body 11 to the fourth columnar body 14. 20 is a force sensor that detects a force in the Z-axis direction that is applied toward 20. Specifically, as will be described later, each of these sensors includes a plurality of capacitive elements. When a force is applied to the force receiving body 10, the force is transmitted to the support substrate 20 through the columnar bodies 11 to 14. Each of the sensors 21 to 24 has a function of detecting a dynamic phenomenon generated in the vicinity of the lower end portion of each of the columnar bodies 11 to 14 by the force transmitted in this way. More specifically, as described in detail later, the function of detecting the inclination of the columnar body by detecting the force generated by the tilting of the columnar body and the entire columnar body are applied to the support substrate. And a function of detecting a pressing force (downward in the figure-force in the Z-axis direction) or a pulling force (upward in the figure + force in the Z-axis direction).

  The detection circuit 30 is a component that performs processing for detecting a force or moment applied to the force receiving body 10 based on capacitance values of a plurality of capacitive elements constituting the sensors 21 to 24, and is an XYZ three-dimensional. A signal indicating force components Fx, Fy, Fz in each coordinate axis direction in the coordinate system and a signal indicating moment components Mx, My, Mz around each coordinate axis are output. Actually, detection of force or moment is performed based on the inclination of the columnar body and the pressing force / tensile force applied to the support substrate.

<<< §2. Principle of detecting force and moment separately >>>
Next, with reference to the front view of FIG. 2, the principle by which the force detection device shown in FIG. 1 can distinguish and detect force and moment will be described. In FIG. 2, only the displacement form of the first columnar body 11 and the second columnar body 12 is shown for convenience of explanation, but the predetermined displacement is also applied to the third columnar body 13 and the fourth columnar body 14. Will occur.

  FIG. 2A shows a state in which no force is applied to the force detection device, and the force receiving body 10 maintains a fixed position with respect to the support substrate 20. Of course, even in this state, since the weight of the force receiving member 10 and the like is applied to the support substrate 20, the support substrate 20 receives some force from the first columnar body 11 to the fourth columnar body 14. However, the force received in this state is a force in a steady state, and even if such a force is detected by the first sensor 21 to the fourth sensor 24, the force output from the detection circuit 30 And the detected value of moment is adjusted to be zero. In other words, the detection circuit 30 is based on the detection results of the sensors 21 to 24 in such a steady state as a reference, and when any change occurs, the change is expressed as a force or moment acting on the force receiving body 10. It has a function to detect.

  Now, let us consider a case where a force + Fx in the positive direction of the X axis is applied to the force receiving member 10 as shown in FIG. 2 (b). This corresponds to the case where a force that pushes the position of the origin O ′ in the right direction in the figure is applied. In this case, as shown in the figure, the force receiving body 10 slides in the right direction in the figure, and the first columnar body 11 and the second columnar body 12 are inclined in the right direction in the figure. Become. Here, the inclination of the first columnar body 11 at this time is referred to as θ1, and the inclination of the second columnar body 12 is referred to as θ2.

  Although not shown in the figure, at this time, the third columnar body 13 and the fourth columnar body 14 are similarly inclined to the right in the figure. Here, the inclination of the third columnar body 13 in the X-axis direction at this time is referred to as θ3, and the inclination of the fourth columnar body 14 in the X-axis direction is referred to as θ4. The angles θ1 to θ4 indicating the degree of inclination in the direction toward the X axis in the XZ plane or in a plane parallel to the XZ plane are referred to as “inclination degree in the X axis direction”.

  Similarly, when a force + Fy in the Y-axis positive direction is applied to the force receiving body 10, the first columnar body 11 to the fourth columnar body 14 are all in the Y-axis positive direction (the depth of the drawing in the drawing). Direction). Here, the angle indicating the degree of inclination in the direction toward the Y axis in the YZ plane or in a plane parallel to the YZ plane will be referred to as “the inclination with respect to the Y axis direction”. As shown in FIG. 2 (b), when a force + Fx in the X-axis positive direction is applied to the force receiving body 10, the inclination of each columnar body in the Y-axis direction is zero.

  In addition, if each columnar body 11-14 inclines, since the distance of the power receiving body 10 and the support substrate 20 will shrink a little, strictly speaking, the power receiving body 10 does not move completely in the X-axis direction. However, if the inclination is relatively small, the amount of movement in the −Z-axis direction can be ignored, so here, for convenience of explanation. Suppose that the force receiving body 10 has moved only in the X-axis direction.

  On the other hand, let us consider a case where a moment + My around the Y-axis acts on the force receiving member 10 as shown in FIG. In FIG. 2 (c), since the Y axis is a vertical axis toward the back side of the paper surface at the position of the origin O, in the figure, the moment + My is the clockwise rotation of the force receiving member 10 around the origin O. It corresponds to a force that rotates in the direction. In the present application, the rotation direction of the right screw when the right screw is advanced in the positive direction of a predetermined coordinate axis is defined as a positive moment around the coordinate axis. As described above, the moment + My is not a force that rotates the force receiving member 10 about the origin O ′ but a force that rotates the origin 10 about the origin O (if the error between the two is within an allowable range, the moment is converted to the origin O It can be handled as a rotational force centered on ′.)

  In this case, as shown in the drawing, the first columnar body 11 has a contracting force acting in the vertical direction, and the second columnar body 12 has a stretching force acting in the vertical direction. As a result, a pressing force (force in the −Z axis direction: here, referred to as force −fz) acts on the support substrate 20 from the first columnar body 11, and the second columnar body 12. Therefore, a pulling force (+ Z-axis direction force: here, referred to as force + fz) is applied to the support substrate 20. At this time, although a pressing force and a pulling force are partially applied to the support substrate 20 from the third columnar body 13 and the fourth columnar body 14, the applied force is totally canceled and becomes zero. .

  As indicated by arrows in FIG. 1, the force Fx in the X-axis direction acting on the force receiving body 10 and the moment My around the Y axis exert a similar displacement action on the force receiving body 10. However, in the force detection device having a structure that takes a dynamic behavior as shown in FIG. 2, when the force Fx in the X-axis direction acts on the force receiving body 10 and the moment My around the Y-axis acts. In this case, the mode of the force transmitted to the support substrate 20 via the four columnar bodies 11 to 14 is different. Therefore, both can be distinguished and detected separately.

  That is, when the force Fx in the X-axis direction is applied, as shown in FIG. 2 (b), the four columnar bodies 11 to 14 are inclined in the X-axis direction to generate the inclinations θ1 to θ4. (Only the displacement mode of the columnar bodies 11 and 12 is illustrated in the figure), and a force corresponding to such inclination is transmitted to the support substrate 20. These inclinations θ1, θ2, θ3, and θ4 are all values indicating the force Fx in the X-axis direction. If the inclination θ is handled with a sign (for example, if the inclination in the X-axis positive direction is treated as positive, and the inclination in the X-axis negative direction is treated as negative), the applied force X in the X-axis direction Fx Can be detected including the sign.

  In the present invention, as will be described later, the inclinations of the respective columnar bodies 11 to 14 are detected as forces applied to the support substrate 20 by the respective sensors 21 to 24. In order to perform such detection, the force applied from each columnar body to the support substrate 20 may be detected for each individual portion. For example, in FIG. 2B, when the stress generated in the connection portion between the first columnar body 11 and the support substrate 20 is considered, the stress is generated in the right side portion and the left side portion of the bottom portion of the first columnar body 11. It can be seen that the direction of the stress is different. That is, in the illustrated example, since the first columnar body 11 is inclined to the right side, a pressing force is generated on the right side portion of the bottom of the first columnar body 11 and presses the upper surface of the support substrate 20 downward. While a force is generated, a pulling force is generated in the left portion, and a force is generated that pulls the upper surface of the support substrate 20 upward. Thus, by detecting the difference in stress between the left and right portions of the bottom of the first columnar body 11, the inclination of the first columnar body 11 can be obtained. The inclination detection of the other columnar bodies 12, 13, and 14 can also be performed by the same method.

  On the other hand, when the moment My around the Y-axis acts, as shown in FIG. 2C, the pressing force −fz and the pulling force + fz are applied to the support substrate 20 from the two columnar bodies 11 and 12. Communicated. The force transmitted in this way is different from the force when the columnar body is inclined. That is, when the columnar body is inclined as shown in FIG. 2 (b), the stress generated at the bottom of the columnar body is different between the right side portion and the left side portion. However, when the moment My is applied as shown in FIG. 2 (c), the pressing force -fz is applied by the entire first columnar body 11, and the tensile force + fz is applied by the entire second columnar body 12. become.

  As described above, with respect to the action of the force Fx in the X-axis direction, the equivalent phenomenon of the inclination in the same direction occurs with respect to the first columnar body 11 to the fourth columnar body 14, whereas the Y-axis With respect to the action of the surrounding moment My, as shown in FIG. 2 (c), with respect to the first columnar body 11 and the second columnar body 12, one applies a pressing force -fz and the other a tensile force + fz. The contradictory event of giving Therefore, the applied moment My can be obtained as a difference between the pulling force + fz and the pressing force −fz, that is, (+ fz) − (− fz) = 2fz.

  Eventually, in order to detect the moment My around the Y axis by this force detection device, the first sensor 21 has a function of detecting the force applied to the support substrate 20 from the entire first columnar body 11. Therefore, the second sensor 22 may have a function of detecting a force applied to the support substrate 20 from the entire second columnar body 12. The first sensor 21 has a function of detecting a force in the Z-axis direction applied to the support substrate 20 from the entire first columnar body 11, and the second sensor 22 is the entire second columnar body 12. If the detection circuit 30 has a function of detecting a force applied to the support substrate 20 from the Z-axis direction, the detection circuit 30 can detect the force detected by the first sensor 21 and the second sensor. Based on the difference between the force in the Z-axis direction detected by 22 and the moment My around the Y-axis of the force acting on the force receiving body 10 can be detected.

  As described above, the principle of detecting the force Fx in the X-axis direction acting on the force receiving member 10 and the moment My around the Y-axis separately from each other has been described with reference to FIG. If the X axis is replaced with the Y axis, the force Fy in the Y axis direction acting on the force receiving member 10 and the moment Mx around the X axis can be distinguished and detected by the same method.

  Further, when a force −Fz in the negative Z-axis direction is applied to the force receiving body 10, a pressing force −fz is applied to the support substrate 20 from all of the four columnar bodies 11 to 14. When the force + Fz in the positive axial direction is applied, the tensile force + fz is applied to the support substrate 20 from all of the four columnar bodies 11 to 14. Therefore, the applied force Fz in the Z-axis direction can be obtained as the sum of the pressing forces −fz applied from the four columnar bodies 11 to 14 or the sum of the pulling forces + fz.

  Furthermore, when the moment Mz around the Z-axis is applied to the force receiving body 10, the four columnar bodies 11 to 14 are inclined clockwise or counterclockwise when observed from above. The moment Mz can also be detected by detecting the inclination directions of the four columnar bodies 11 to 14.

<<< §3. Structure of specific embodiment >>
Subsequently, main structural portions of the force detection device according to the specific embodiment of the present invention will be described with reference to FIGS.

  FIG. 3 is a top view of the force detection device according to the basic embodiment of the present invention. FIG. 4 shows a side cross-sectional view of the device taken along the XZ plane, and FIG. 5 shows a side cross-sectional view taken along the YZ plane. As shown in FIG. 4 or FIG. 5, the basic components of this force detection device are a force receiving body 100, an intermediate body 200, and a support substrate 300, all of which have a square shape whose upper surface is parallel to the XY plane. The plate-shaped member which did is made into the basic form. 4 and 5 are side sectional views at different cutting positions, but the geometric structures appearing in the drawings are exactly the same. The difference between them is only the sign of each part. This is because the basic structure of this device is plane symmetric with respect to the XZ plane and also plane symmetric with respect to the YZ plane.

  Similar to the example described in §1, in this example, an XYZ three-dimensional coordinate system and an X′Y′Z ′ auxiliary coordinate system obtained by translating the coordinate system in the Z-axis direction are defined. The X′Y′Z ′ auxiliary coordinate system is a coordinate system having the origin O ′ at the center position of the force receiving body 100. On the other hand, the origin O of the XYZ three-dimensional coordinate system is defined at a position where the upper surface center point of the support substrate 300 is slightly shifted in the positive direction of the Z axis. 4 and 5, the origin O is slightly shifted from the upper surface of the support substrate 300, and the X axis and the Y axis are slightly shifted from the upper surface position of the support substrate 300 for this reason.

  In the first place, the XYZ three-dimensional coordinate system is a conceptually defined coordinate system, and no matter where the origin O is defined, the physical structure of the force detection device is not affected. However, for a user who intends to perform highly accurate measurement using this force detection device, the moment accurately detected by this detection device is about a coordinate axis having a specific origin O. It is necessary to clarify that it is a moment. As will be described later, the correction for eliminating the other-axis interference that is the point of the present invention is a correction that cancels out the interference with respect to the moment around the coordinate axis having the specific origin O. Therefore, in carrying out the present invention, it is necessary to set a specific origin O so that such correction has an accurate meaning.

  This specific origin O may be defined at the position of the upper surface center point of the support substrate 300 as in the example described in §1. However, in the case of the embodiment shown here, the present inventor believes that a more preferable result can be obtained if the position of the origin O is defined slightly upward. As will be described later, in the present invention, as each of the sensors 21 to 24, a sensor (capacitance element) is used to detect a force (inclination) applied to the lower end of each columnar body. This is because it is considered most preferable to define a coordinate system in which the XY plane is located at the center position of the capacitive element, that is, at an intermediate position between a pair of electrodes constituting the capacitive element. Therefore, in the case of the embodiment shown here, the position of the origin O is above the center point of the upper surface of the support substrate 300 by ½ of the distance between the pair of electrodes constituting the capacitive element, when the thickness of the electrode is ignored. It will be the position moved to.

  However, since it is not easy to theoretically analyze the ideal position of the origin O, it is not always optimal to define the origin O at the above-mentioned position depending on the structure of the actual force detection device. Absent. The position of the origin O does not need to be defined so strictly. If it is defined at the upper surface near the center of the support substrate or a predetermined point above it, the effect of the present invention can be obtained sufficiently in practice.

  Now, the force receiving body 100, the intermediate body 200, and the support substrate 300 made of a plate-like member having a square top surface are all parallel to the XY plane, and each side has an X axis or They are arranged so as to be parallel to the Y axis.

  As shown in FIG. 3, the force receiving body 100 is basically a plate-like member having a square upper surface, but four cylindrical protrusions 110, 120, 130, and 140 are directed downward from the lower surface. It is growing. FIG. 6 is a cross-sectional view showing a state where the force receiving body 100 is cut along the X′Y ′ plane.

  As shown in FIG. 6, annular grooves G11, G12, G13, and G14 are formed around the base portions of the four cylindrical protrusions 110, 120, 130, and 140, and the groove G11. , G12, G13, and G14, the plate-like force receiving member 100 is provided with flexible upper end side thin portions 115, 125, 135, and 145 as shown in FIGS. Is formed. Eventually, the four cylindrical protrusions 110, 120, 130, and 140 are connected to the plate-shaped force receiving body 100 through the upper-end-side thin portions 115, 125, 135, and 145.

  On the other hand, the intermediate body 200 is a member bonded to the upper surface of the support substrate 300, and is basically a plate-shaped member having a square upper surface. As shown in FIGS. 4 and 5, four cylindrical protrusions 210, 220, 230, and 240 extend upward from the upper surface of the intermediate body 200. Annular grooves G21, G22, G23, and G24 are formed around the base portions of the four cylindrical protrusions 210, 220, 230, and 240. Further, on the lower surface of the intermediate body 200, Cylindrical grooves G31, G32, G33, and G34 are formed. The groove portions G21, G22, G23, G24 provided on the upper surface of the intermediate body 200 and the groove portions G31, G32, G33, G34 provided on the lower surface are all center axes of the cylindrical protrusion portions 210, 220, 230, 240. It has a circular outline of the same size around the position of.

  As shown in FIG. 4, the lower end side thin portion 215 exists as a boundary wall between the groove portions G21 and G31, and the lower end side thin portion 225 exists as a boundary wall between the groove portions G22 and G32. Further, as shown in FIG. 5, a lower end side thin portion 235 exists as a boundary wall between the groove portions G23 and G33, and a lower end side thin portion 245 exists as a boundary wall between the groove portions G24 and G34. To do.

  FIG. 7 is a cross-sectional view showing a state in which the intermediate body 200 shown in FIGS. 4 and 5 is cut along a cutting line 7-7. The state in which the groove portions G21, G22, G23, and G24 are formed around the four cylindrical protrusion portions 210, 220, 230, and 240 is clearly shown. 8 is a cross-sectional view showing a state in which the intermediate body 200 shown in FIGS. 4 and 5 is cut along the XY plane, and the arrangement of the grooves G31, G32, G33, and G34 is clearly shown. ing.

  As shown in FIG. 9, the support substrate 300 bonded to the lower surface of the intermediate body 200 is a complete plate-like member having a square upper surface, and fixed electrodes E1 to E8 and F1 to F8 are formed on the upper surface. Is arranged. As will be described later, the fixed electrodes E1 to E8 are electrodes fixed to the upper surface of the support substrate 300 in order to form the main capacitive elements C1 to C8, respectively, and are referred to as “main fixed electrodes” herein. On the other hand, the fixed electrodes F1 to F8 are electrodes fixed to the upper surface of the support substrate 300 in order to form the sub-capacitance elements D1 to D8, respectively, and are referred to as “sub-fixed electrodes” here. In FIG. 9, in order to clearly show the shapes of these 16 fixed electrodes, the inside of each electrode is hatched (hatching in FIG. 9 is not for showing a cross section).

  The bottom surfaces of the four cylindrical protrusions 110, 120, 130, 140 extending downward from the force receiving body 100 side are the four cylindrical protrusions 210, 220, 230, 240 extending upward from the intermediate body 200 side. Bonded to the top surface. Here, as shown in FIG. 4, a columnar structure formed by joining the columnar projection 110 and the columnar projection 210 is referred to as a first columnar body T1, and the columnar projection 120 and the columnar projection A columnar structure formed by joining the portion 220 will be referred to as a second columnar body T2. Further, as shown in FIG. 5, a columnar structure formed by joining the columnar projection 130 and the columnar projection 230 is referred to as a third columnar body T3, and the columnar projection 140 and the columnar projection A columnar structure formed by joining 240 is referred to as a fourth columnar body T4.

  As can be seen from the top view of FIG. 3, when the projection positions of the four columnar bodies T1 to T4 on the XY plane are considered, the first columnar body T1 has a central axis parallel to the Z axis. And the central axis of the second columnar body T2 is parallel to the Z axis, and the central axis is the X axis of the X axis. The third columnar body T3 is disposed at a position intersecting with the negative portion, and the third columnar body T3 is disposed at a position where the central axis is parallel to the Z axis and the central axis intersects with the positive portion of the Y axis. The fourth columnar body T4 is disposed at a position where the central axis is parallel to the Z axis and the central axis intersects the negative portion of the Y axis.

  Further, as shown in FIG. 4, the upper end of the first columnar body T1 is connected to the force receiving body 100 using the flexible upper end side thin portion 115 as a connecting member, and the second columnar body T2 The upper end is connected to the force receiving body 100 using the flexible upper end side thin portion 125 as a connecting member. As shown in FIG. 5, the upper end of the third columnar body T3 has flexibility. The upper end side thin portion 135 is connected to the force receiving body 100 as a connecting member, and the upper end of the fourth columnar body T4 is connected to the force receiving body 100 using the flexible upper end side thin portion 145 as a connecting member. Has been. Thus, each upper end side thin portion 115, 125, 135, 145 is connected to the power receiving body 100 at its periphery, and its lower surface central portion is connected to the upper end of each columnar body T1, T2, T3, T4. Will be. .

  On the other hand, as shown in FIG. 4, the lower surface of the first columnar body T <b> 1 is joined to the center of the lower end side thin portion 215 that functions as a connecting member, and the periphery of the lower end side thin portion 215 is interposed via the intermediate body 200. Are connected to the support substrate 300, and the lower surface of the second columnar body T2 is joined to the center of the lower end side thin portion 225 functioning as a connecting member. And connected to the support substrate 300. Similarly, as shown in FIG. 5, the lower surface of the third columnar body T3 is joined to the center of the lower end side thin portion 235 that functions as a connecting member. The lower surface of the fourth columnar body T4 is joined to the center of the lower end side thin portion 245 functioning as a connecting member, and the periphery of the lower end side thin portion 245 is an intermediate body. It is connected to the support substrate 300 through 200.

  The lower end side thin portions 215, 225, 235, and 245 are also disk-shaped members having flexibility, and a part of the intermediate body 200 supports the disk-shaped member on the support substrate 300. Is functioning as Eventually, the lower end side thin portions 215, 225, 235, and 245 are pedestal around so that the lower end side thin portions 215, 225, 235, and 245 are arranged parallel to the upper surface of the support substrate 300 at an upper position at a predetermined distance from the upper surface of the support substrate 300. The center of the upper surface is connected to the lower end of each columnar body T1, T2, T3, T4.

  In the illustrated embodiment, the power receiving body 100 is an insulating substrate (for example, a ceramic substrate), the intermediate body 200 is a conductive substrate (for example, a metal substrate such as stainless steel, aluminum, titanium, etc.), and the support substrate 300 is an insulating substrate (for example). For example, a ceramic substrate is used. Of course, the material of each part is not limited to these, For example, you may comprise the power receiving body 100 with metal substrates, such as stainless steel, aluminum, and titanium. The upper end side thin portions 115, 125, 135, and 145 and the lower end side thin portions 215, 225, 235, and 245 are configured to have flexibility by making the thickness thinner than other portions of the substrate. Part.

  In this embodiment, since the lower end side thin portions 215, 225, 235, and 245 are made of a conductive material, they have flexibility and conductivity. When force is applied to the force receiving body 100, the lower end side thin portions 215, 225, 235, and 245 are deformed to cause displacement, and as a result, the columnar bodies T1, T2, T3, and T4 are also displaced. It will be. Therefore, the lower end side thin portions 215, 225, 235, and 245 having conductivity serve as displacement electrodes themselves.

  As shown in FIG. 9, on the upper surface of the support substrate 300, main fixed electrodes E1, E2 and sub fixed electrodes F6, F8 are formed in the vicinity of the lower end of the first columnar body T1. As shown in FIG. 4, the lower end thin portion 215 made of a conductive material functions as a single common displacement electrode facing all of the four fixed electrodes. For this reason, a capacitive element is formed by each fixed electrode and the portion of the common displacement electrode facing this. Here, the capacitive elements constituted by the main fixed electrodes E1 and E2 and the sub fixed electrodes F6 and F8 and the opposing portion of the common displacement electrode (the lower end side thin portion 215) are respectively represented as the main capacitive elements C1 and C2 and the subcapacitors. These will be referred to as elements D6 and D8.

  Eventually, one electrode (common displacement electrode) is in the lower end side thin portion in the space (groove portion G31) sandwiched between the lower end side thin portion 215 of the first columnar body T1 and the upper surface of the support substrate 300 facing this. 215, the other electrodes (main fixed electrodes E1, E2 and auxiliary fixed electrodes F6, F8) are formed on the upper surface of the support substrate 300 by four capacitive elements C1, C2, D6, D8. One sensor S1 is configured. The first sensor S1 functions to detect the inclination of the first columnar body T1 and the pressing force and tensile force applied to the support substrate 300 from the first columnar body T1.

  Further, as shown in FIG. 9, main fixed electrodes E3 and E4 and auxiliary fixed electrodes F5 and F7 are formed on the upper surface of the support substrate 300 in the vicinity of the lower end of the second columnar body T2. As shown in FIG. 4, the lower end side thin portion 225 made of a conductive material functions as one common displacement electrode facing all of the four fixed electrodes. For this reason, a capacitive element is formed by each fixed electrode and the portion of the common displacement electrode facing this. Here, the capacitive elements constituted by the main fixed electrodes E3 and E4 and the sub fixed electrodes F5 and F7 and the opposing portion of the common displacement electrode (the lower end side thin portion 225) are represented by the main capacitive elements C3 and C4 and the sub capacitors, respectively. These will be referred to as elements D5 and D7.

  After all, one electrode (common displacement electrode) is in the lower end side thin portion in the space (groove portion G32) sandwiched between the lower end side thin portion 225 of the second columnar body T2 and the upper surface of the support substrate 300 facing this. The four capacitive elements C3, C4, D5, and D7 formed on the lower surface of 225 and the other electrodes (main fixed electrodes E3 and E4 and auxiliary fixed electrodes F5 and F7) formed on the upper surface of the support substrate 300 Two sensors S2 are configured. The second sensor S2 functions to detect the inclination of the second columnar body T2 and the pressing force and tensile force applied to the support substrate 300 from the second columnar body T2.

  Furthermore, as shown in FIG. 9, main fixed electrodes E5 and E6 and auxiliary fixed electrodes F2 and F4 are formed on the upper surface of the support substrate 300 at positions near the lower end of the third columnar body T3. As shown in FIG. 5, the lower-side thin portion 235 made of a conductive material functions as one common displacement electrode facing all of these four fixed electrodes. For this reason, a capacitive element is formed by each fixed electrode and the portion of the common displacement electrode facing this. Here, the capacitive elements constituted by the main fixed electrodes E5 and E6 and the sub fixed electrodes F2 and F4 and the opposing portion of the common displacement electrode (the lower end side thin portion 235) are the main capacitive elements C5 and C6 and the sub capacitors, respectively. These will be referred to as elements D2 and D4.

  Eventually, one electrode (common displacement electrode) is in the lower end side thin portion in the space (groove portion G33) sandwiched between the lower end side thin portion 235 of the third columnar body T3 and the upper surface of the support substrate 300 facing this. 235, the other electrodes (main fixed electrodes E5, E6 and auxiliary fixed electrodes F2, F4) are formed on the upper surface of the support substrate 300 by four capacitive elements C5, C6, D2, D4. 3 sensors S3 are configured. The third sensor S3 functions to detect the inclination of the third columnar body T3 and the pressing force and tensile force applied to the support substrate 300 from the third columnar body T3.

  Similarly, as shown in FIG. 9, main fixed electrodes E7 and E8 and auxiliary fixed electrodes F1 and F3 are formed on the upper surface of the support substrate 300 in the vicinity of the lower end of the fourth columnar body T4. As shown in FIG. 5, the lower-side thin portion 245 made of a conductive material functions as one common displacement electrode facing all of these four fixed electrodes. For this reason, a capacitive element is formed by each fixed electrode and the portion of the common displacement electrode facing this. Here, the capacitive elements constituted by the main fixed electrodes E7, E8 and the sub fixed electrodes F1, F3 and the opposing portion of the common displacement electrode (lower end thin portion 245) are respectively referred to as the main capacitive elements C7, C8 and the sub capacitance. These will be referred to as elements D1 and D3.

  Eventually, one electrode (common displacement electrode) is in the lower end thin portion in the space (groove G34) sandwiched between the lower end thin portion 245 of the fourth columnar body T4 and the upper surface of the support substrate 300 facing this. The other electrodes (main fixed electrodes E7, E8 and sub fixed electrodes F1, F3) formed on the lower surface of H.245 are formed by four capacitive elements C7, C8, D1, D3 formed on the upper surface of the support substrate 300. Four sensors S4 are configured. The fourth sensor S4 functions to detect the inclination of the fourth columnar body T4 and the pressing force or tensile force applied to the support substrate 300 from the fourth columnar body T4.

  Here, an example in which the lower end side thin portions 215 to 245 are made of a conductive material and the lower end side thin portions 215 to 245 themselves are used as the common displacement electrodes is shown. However, the lower end side thin portions 215 to 245 are insulative. In the case of using a material, a conductive electrode layer serving as a common displacement electrode may be formed on the lower surface. Of course, since the displacement electrodes do not necessarily have to be a common electrode, individual displacement electrodes facing each of the four fixed electrodes may be provided on the lower surface of each lower end side thin portion. It is also possible to use four individual electrodes as the displacement electrodes provided on the lower end side thin portion and one common electrode as the fixed electrode provided on the support substrate 300. However, practically, in order to simplify the wiring, as shown in the illustrated example, the lower end side thin portions 215 to 245 are made of a conductive material, and the lower end side thin portions 215 to 245 themselves are used as common displacement electrodes. It is preferable to use it.

  Now, it can be seen that the force detection device according to the embodiment described with reference to FIGS. 3 to 9 is provided with the same components as the force detection device shown in FIG. That is, the plate-shaped power receiving body 100 corresponds to the power receiving body 10, the plate-shaped support substrate 300 corresponds to the support substrate 20, the columnar bodies T1 to T4 correspond to the columnar bodies 11 to 14, Sensors S1 to S4 correspond to the sensors 21 to 24, respectively. Therefore, if the detection circuit 30 is added to the structure shown in FIGS. 3 to 9, the force detection device shown in FIG. 1 can be realized.

  In practice, it is preferable that the peripheral contour portion of the intermediate body 200 is extended upward and the control walls 250 and 260 are formed as in the example shown in FIG. The control wall 250 is a wall that surrounds the periphery of the force receiving body 100 from four directions, and the control wall 260 is a wall that surrounds the periphery of the upper surface of the force receiving body 100 in a frame shape. In such a structure, a gap having a dimension d1 is formed between the lower surface of the force receiving body 100 and the upper surface of the intermediate body 200, and a gap having a dimension d2 is formed between the upper surface of the force receiving body 100 and the control wall 260. A gap is formed between the side surface of the force receiving body 100 and the control wall 250 with a dimension d3. Therefore, even if an excessive force is applied to the force receiving body 100, the downward, upward, and lateral displacements of the force receiving body 100 are limited to d1, d2, and d3, respectively. It is possible to prevent the structural parts such as the parts T1 to T4 from being damaged.

<<< §4. Detection operation using only main capacitance element >>
Subsequently, a basic detection operation of the force detection device illustrated in FIG. 10 will be described with reference to FIGS. As described in §2, this apparatus is configured such that the force Fx in the X-axis direction, the force Fy in the Y-axis direction, the force Fz in the Z-axis direction, the force Fz in the Z-axis direction, and the X-axis when the support substrate 300 is fixed It has a function of independently detecting six components of force, that is, a moment Mx around the moment, a moment My around the Y axis, and a moment Mz around the Z axis.

  As shown in FIG. 9, eight main fixed electrodes E <b> 1 to E <b> 8 are formed on the support substrate 300, and these main fixed electrodes E <b> 1 to E <b> 8 are opposed to common displacement electrodes (lower end thin portions 215 to 245). ) Constitute eight main capacitive elements C1 to C8. In §4, an operation for detecting the above six force components using only these eight main capacitive elements C1 to C8 will be described. A feature of the present invention is that accurate detection is performed by eliminating interference of other-axis components using eight sub-capacitance elements D1 to D8. This feature will be described in §6. To do.

  Now, in the XYZ three-dimensional coordinate system having the origin O at the position shown in FIG. 10, the force X in the positive direction of the X axis + Fx, the force in the positive direction of the Y axis + Fy, and the positive value of the Z axis. When the force in the direction + Fz, the positive moment about the X axis + Mx, the positive moment about the Y axis + My, and the positive moment about the Z axis + Mz are respectively applied, the eight main capacitive elements C1 to C8 (Changes in the capacitance values of the eight sub-capacitance elements D1 to D8 will be described in §6).

  FIG. 11 is a side sectional view showing a deformation mode of the structure when a force + Fx in the positive direction of the X-axis acts on the force receiving body 100 in the force detection device shown in FIG. Similarly, FIG. 12 shows a deformation mode when a positive force + Fz in the Z axis acts, and FIG. 13 shows a deformation mode when a positive moment + My around the Y axis acts.

  On the other hand, FIG. 14 shows how the capacitance values of the main capacitive elements C1 to C8 (the symbols E1 to E8 in parentheses indicate the corresponding main fixed electrodes) change when the six force components act. “0” indicates no change, “+ Δ” indicates an increase, and “−Δ” indicates a decrease. Note that the absolute value of Δ in each column in this table does not necessarily take the same value even if the absolute value of the acting force is the same, and is determined by the shape and arrangement of each capacitive element. To a predetermined eigenvalue.

  More specifically, the absolute values of Δ described in the column of the same row for the capacitive elements having symmetry in shape and arrangement are equal to each other, but the absolute values of Δ for all the columns are mutually Not equal. For example, the absolute values of Δ shown in the columns C1 to C8 in the third row (+ Fz row) are equal to each other because symmetry is ensured in the shape and arrangement of these capacitive elements. Even in the case of Δ in the column, for example, “+ Δ” in the second row (capacity change when force + Fy is applied) and “−Δ” (force + Fz is applied in the third row) The absolute value of the change Δ is different even if the applied force + Fy, + Fz has the same absolute value.

  As described above, the symbol “Δ” shown in the table of the present application does not indicate a specific value, but indicates a “capacitance value change occurring in the main capacitance element”. However, as shown in FIG. 9, when each fixed electrode has a shape and arrangement having geometric symmetry with the X-axis and Y-axis as symmetry axes, “Δ” in each column of the table in FIG. The value of “” is equal to the value of “Δ” in any other column where the geometric conditions are the same.

  Next, the reason why the capacitance values of the main capacitive elements C1 to C8 change as shown in the table of FIG. 14 when six force components act on the force receiving member 100 will be described.

  First, when a force + Fx in the X-axis positive direction acts on the force receiving body 100, as shown in FIG. 11, each of the columnar bodies T1 to T4 is in the right direction (X-axis positive direction). ) (A deformation mode corresponding to FIG. 2 (b)). For this reason, in the lower end side thin portions 215, 225, 235, and 245 that function as common displacement electrodes, the right half part in the figure is deformed downward in the figure, and the left half part is in the upper part in the figure. Deform.

  Therefore, referring to the plan view of FIG. 9, the distance between the fixed electrodes E5 and E7 arranged in the right half portion to which the lower end side thin portion approaches is reduced. About fixed electrode E6, E8 arrange | positioned in the left half part from which a side thin part goes away, the distance between counter electrodes spreads. That is, the electrode interval between the capacitive elements C5 and C7 is narrowed and the capacitance value is increased, whereas the electrode interval between the capacitive elements C6 and C8 is widened and the capacitance value is decreased. Therefore, the columns of C5 and C7 in the row of “+ Fx” in the table of FIG. 14 are “+ Δ”, and the columns of C6 and C8 are “−Δ”.

  At this time, the distance between the fixed electrodes E1, E2, E3, E4 and the common displacement electrode located above the fixed electrode E1, E2, E3, E4 is reduced in part (right half part), but is separated in another part (left half part). Therefore, the total capacitance does not change. The first row (+ Fx row) in the table of FIG. 14 shows such a change in capacitance value for each of the capacitive elements C1 to C8.

  Conversely, when the force -Fx in the negative X-axis direction is applied, each of the columnar bodies T1 to T4 is inclined in the left direction (X-axis negative direction) opposite to the example shown in FIG. The relationship of the increase / decrease change of the capacitance value is reversed, and the result of “+” and “−” being reversed with respect to the first row (+ Fx row) of the table of FIG. 14 is obtained.

  On the other hand, when a force + Fy in the Y-axis positive direction is applied to the force receiving body 100, a phenomenon occurs in which the change mode when the force + Fx is applied is rotated by 90 ° when viewed from the top. . That is, it can be seen that the electrode interval between the capacitive elements C1 and C3 is narrowed and the capacitance value is increased, whereas the electrode interval between the capacitive elements C2 and C4 is widened and the capacitance value is decreased. Regarding the capacitive elements C5 to C8, the electrode spacing is partially expanded and partially decreased, and therefore, the capacitance value does not change in total. The second row (+ Fy row) in the table of FIG. 14 shows such a change in capacitance value for each of the capacitive elements C1 to C8. On the contrary, when the force -Fy in the negative Y-axis direction is applied, the relationship between the increase and decrease of the capacitance value is reversed, and the result of reversing “+” and “−” is obtained.

  Further, when a force + Fz in the positive direction of the Z-axis is applied to the force receiving body 100, each of the columnar bodies T1 to T4 is pulled against the upper surface of the support substrate 300 as shown in FIG. Since force is applied, the electrode interval of each of the capacitive elements C1 to C8 is widened, and the capacitance value is reduced. The third row (+ Fz row) in the table of FIG. 14 shows such a change. On the contrary, when the force −Fz in the negative Z-axis direction acts on the force receiving body 100, each of the columnar bodies T1 to T4 exerts a pressing force on the upper surface of the support substrate 300. The electrode intervals of the capacitive elements C1 to C8 are narrowed, and the capacitance value is increased. Accordingly, a result obtained by reversing “+” and “−” with respect to the result shown in the third row (+ Fz row) of the table of FIG. 14 is obtained.

  Next, let us consider a case where a moment acts on the force receiving member 100. FIG. 13 shows a change mode when a positive moment + My around the Y-axis acts on the force receiving body 100. That is, a downward pressing force −fz is applied to the support substrate 300 from the columnar body T1, and an upward pulling force + fz is applied to the support substrate 300 from the columnar body T2. Therefore, referring to the plan view of FIG. 9, the electrode interval between the capacitive elements C1 and C2 is narrowed, and the capacitance value is increased. On the other hand, the electrode interval between the capacitive elements C3 and C4 is increased, and the capacitance value is decreased. The fifth row (+ My row) of the table in FIG. 14 shows such a change in capacitance value for each of the capacitive elements C1 to C8. Conversely, when a negative moment -My around the Y axis acts, the relationship between the increase and decrease of the capacitance value is reversed, and the result of reversing "+" and "-" is obtained.

  Further, when a positive moment + Mx around the X axis is applied to the force receiving member 100, a phenomenon occurs in which the change mode when the above-described moment + My is applied is rotated by 90 ° when viewed from the top. That is, a downward pressing force −fz is applied to the support substrate 300 from the columnar body T4, and an upward pulling force + fz is applied to the support substrate 300 from the columnar body T3. Therefore, the electrode interval between the capacitive elements C7 and C8 is narrowed, and the capacitance value is increased. On the other hand, the electrode interval of the capacitive elements C5 and C6 is widened, and the capacitance value is decreased. The fourth row (+ Mx row) in the table of FIG. 14 shows such a change in capacitance value for each of the capacitive elements C1 to C8. Conversely, when a negative moment -Mx around the X axis is applied, the relationship between the increase and decrease of the capacitance value is reversed, and the result of reversing "+" and "-" is obtained.

  Finally, let us consider a case where a moment Mz around the Z-axis acts on the force receiving body 100. First, referring to FIG. 9, when a positive moment + Mz (a counterclockwise moment on the plan view of FIG. 9) is applied to the force receiving member 100, four columnar bodies. Let us consider in which direction T1 to T4 are inclined.

  In this case, the first columnar body T1 (arranged on the fixed electrodes E1 and E2 in the drawing) is inclined upward in FIG. 9, and the capacitance between the electrodes of the capacitive element C1 is reduced and the capacitance value is increased. As a result, the distance between the electrodes of the capacitive element C2 increases, and the capacitance value decreases. The second columnar body T2 (arranged on the fixed electrodes E3 and E4 in the figure) is inclined downward in FIG. 9, the electrode interval of the capacitive element C4 is narrowed, and the capacitance value is increased. The electrode spacing of C3 is increased and the capacitance value is reduced. The third columnar body T3 (arranged on the fixed electrodes E5 and E6 in the figure) is inclined leftward in FIG. 9, and the electrode interval of the capacitive element C6 is narrowed to increase the capacitance value, thereby increasing the capacitance. The electrode interval of the element C5 is increased and the capacitance value is decreased. The fourth columnar body T4 (arranged on the fixed electrodes E7 and E8 in the figure) is inclined to the right in FIG. 9, the electrode interval of the capacitive element C7 is reduced, the capacitance value is increased, and the capacitance is increased. The electrode interval of the element C8 is increased and the capacitance value is decreased.

  Eventually, when a positive moment + Mz around the Z-axis acts on the force receiving member 100, an increase / decrease result as shown in the sixth line of FIG. 14 is obtained. Further, when a negative moment -Mz around the Z-axis acts on the force receiving member 100, the relationship between the increase and decrease of the capacitance value is reversed, and the result that "+" and "-" are reversed is obtained. Will be.

  Considering that the results shown in the table of FIG. 14 are obtained, the detection circuit 30 has the capacitance values of the eight sets of main capacitance elements C1 to C8 (here, the capacitance values themselves are the same). If a circuit that performs an operation based on the expression shown in FIG. 15 is prepared based on (denoted by reference symbols C1 to C8), six components Fx, Fy, Fz, Mx, My, and Mz can be obtained. it can.

  For example, the formula Fx = C5-C6 + C7-C8 shown in FIG. 15 is based on the result of the first row (+ Fx row) of the table of FIG. Here, the difference (C5-C6) indicates the degree of inclination in the X-axis direction of the columnar body T3 detected by the third sensor S3, and the difference (C7-C8) is detected by the fourth sensor S4. The inclination about the X-axis direction of columnar body T4 is shown. Therefore, the above equation is based on the sum of the inclinations of the columnar bodies T3 and T4 detected by the third and fourth sensors S3 and S4 with respect to the X-axis direction. This means that the direction component Fx can be detected. This is based on the detection principle shown in FIG.

  Further, the expression Fy = C1-C2 + C3-C4 shown in FIG. 15 is based on the result of the second row (+ Fy row) of the table of FIG. Here, the difference (C1-C2) indicates the degree of inclination in the Y-axis direction of the columnar body T1 detected by the first sensor S1, and the difference (C3-C4) is detected by the second sensor S2. The inclination about the Y-axis direction of columnar body T2 is shown. Therefore, the above equation is based on the sum of the slopes of the columnar bodies T1 and T2 detected by the first and second sensors S1 and S2 with respect to the Y-axis direction. This means that the direction component Fy can be detected. This is also based on the detection principle shown in FIG.

  Further, the formula Fz = − (C1 + C2 + C3 + C4 + C5 + C6 + C7 + C8) shown in FIG. 15 is based on the result of the third row (+ Fz row) of the table of FIG. 14, and is obtained by the first to fourth sensors S1 to S4. This means that the Z-axis direction component Fz of the force acting on the force receiving body 100 can be detected based on the detected sum of the forces in the Z-axis direction of the columnar bodies T1 to T4. The leading minus sign is based on the Z axis direction.

  On the other hand, the expression Mx = −C5−C6 + C7 + C8 shown in FIG. 15 is based on the result of the fourth row (+ Mx row) of the table of FIG. Here, -C5-C6 indicates the force in the Z-axis direction applied from the columnar body T3 detected by the third sensor S3, and C7 + C8 is the columnar body T4 detected by the fourth sensor S4. The force regarding Z-axis direction applied from is shown. Therefore, the above equation is obtained by the force related to the Z-axis direction of the third columnar body T3 detected by the third sensor S3 and the force related to the Z-axis direction of the fourth columnar body T4 detected by the fourth sensor S4. This means that the moment Mx around the X axis of the force acting on the force receiving body 100 can be detected based on the difference between the two.

  Also, the equation My = C1 + C2-C3-C4 shown in FIG. 15 is based on the result of the fifth row (+ My row) of the table of FIG. Here, C1 + C2 represents the force in the Z-axis direction applied from the columnar body T1 detected by the first sensor S3, and −C3 to C4 represents the columnar body T2 detected by the second sensor S2. The force regarding Z-axis direction applied from is shown. Therefore, the above equation is expressed as follows. The force related to the Z-axis direction of the first columnar body T1 detected by the first sensor S1 and the force related to the Z-axis direction of the second columnar body T2 detected by the second sensor S2. This means that the moment My around the Y-axis of the force acting on the force receiving body 100 can be detected based on the difference between. This is based on the detection principle shown in FIG.

  Finally, the formula Mz = C1-C2-C3 + C4-C5 + C6 + C7-C8 shown in FIG. 15 is based on the result of the sixth row (+ Mz row) of the table of FIG. Here, the difference (C1-C2) indicates the inclination of the columnar body T1 in the Y-axis direction detected by the first sensor S1, and the difference (−C3 + C4) is the columnar shape detected by the second sensor S2. The inclination of the body T2 in the Y-axis direction is shown, the difference (−C5 + C6) shows the inclination of the columnar body T3 in the X-axis direction detected by the third sensor S3, and the difference (C7−C8) is 4 shows the inclination of the columnar body T4 detected by the four sensors S4 in the X-axis direction.

  As described above, an apparatus that can obtain six components of Fx, Fy, Fz, Mx, My, and Mz while being one force detection apparatus is extremely useful industrially. In applications such as operation control of robots and industrial machines, there is a great demand for force detection devices that can detect force and moment clearly. The force detection device shown here can be said to be a device suitable for such an application. For example, if the force detection device shown in FIG. 10 is used as a joint portion between a robot arm and a wrist, the support substrate 300 may be attached to the arm side and the force receiving body 100 may be attached to the wrist side. Then, it is possible to detect the force and moment applied to the wrist side with respect to the arm.

<<< §5. Interference of other axis components >>
In §4, the operation of detecting six force components using only the eight main capacitance elements C1 to C8 in the force detection device shown in FIG. 10 has been described. Such a detection principle itself is already disclosed in Patent Document 3 described above.

  According to this detection principle, an accurate detection value that is not subject to interference from other axis components should be obtained. For example, the other-axis component should be excluded from the detected value of the force Fx obtained by using the equation Fx = C5-C6 + C7-C8 shown in FIG. That is, in the table of FIG. 14, when the force Fy and the moment My are applied, the columns C5 to C8 are all “0”, so the detection value Fx obtained by the above equation is caused by Fy and My. It does not contain any ingredients. On the other hand, in the table of FIG. 14, the column of C5 to C8 when the force Fz and the moments Mx and Mz are applied is “+ Δ” or “−Δ”, but from the geometric symmetry of each electrode, Since the absolute values of “Δ” written in the same row are equal, the calculation result of Fx = C5−C6 + C7−C8 is 0. Eventually, the value obtained using the formula Fx = C5−C6 + C7−C8 includes only the component of the force Fx.

  Similarly, the value obtained by using the expression Fy = C1-C2 + C3-C4 shown in FIG. 15 includes only the component of the force Fy. Further, the detection value of the force Fz obtained by using the formula Fz = − (C1 + C2 + C3 + C4 + C5 + C6 + C7 + C8) shown in FIG. 15 is also a value that does not include other axis components. That is, in the table of FIG. 14, the absolute value of “Δ” described in the same row is equal because of the geometric symmetry of each electrode. Therefore, if the sum of C1 to C8 is taken for each row, the Fz row Except for all, the sum is 0. This means that the value obtained using the formula Fz = − (C1 + C2 + C3 + C4 + C5 + C6 + C7 + C8) includes only the component of the force Fz.

  Next, consider the detected value of the moment Mx obtained using the equation Mx = −C5−C6 + C7 + C8 shown in FIG. In the table of FIG. 14, since the columns C5 to C8 when the force Fy and the moment My are applied are all “0”, the detection value Mx obtained by the above equation includes components due to Fy and My. Is not included. On the other hand, in the table of FIG. 14, the column of C5 to C8 when the forces Fx, Fz and moment Mz are applied is “+ Δ” or “−Δ”, but from the geometric symmetry of each electrode, Since the absolute values of “Δ” described in the same row are equal, the calculation result of Mx = −C5−C6 + C7 + C8 is 0. Eventually, the value obtained using the equation Mx = −C5−C6 + C7 + C8 includes only the component of the moment Mx.

  Similarly, the value obtained using the equation My = C1 + C2-C3-C4 shown in FIG. 15 includes only the component of the moment My. Further, the detected value of the moment Mz obtained by using the equation Mz = C1-C2-C3 + C4-C5 + C6 + C7-C8 shown in FIG. 15 is also a value that does not include other axis components. That is, in the table of FIG. 14, the absolute value of “Δ” described in the same row is equal because of the geometric symmetry of each electrode. Therefore, if the calculation based on the above formula is performed for each row, the Mz row All other than are 0. This means that the value obtained using the equation Mz = C1-C2-C3 + C4-C5 + C6 + C7-C8 includes only the component of the moment Mz.

  However, in practice, the detection operation described in §4 cannot perform accurate detection that completely eliminates interference from other axis components. FIG. 16 is a graph showing a measurement result in which other-axis interference occurs in the force Fy in the Y-axis direction due to the moment Mx around the X-axis when detection based on the principle shown in FIGS. 14 and 15 is performed. That is, this graph is based on an arithmetic expression of Mx = −C5−C6 + C7 + C8 when only the moment Mx around the X axis is applied to the force receiving body 100 by making a prototype of the force detection device shown in FIG. The detection value V (Mx) obtained by the calculation and the detection value V (Fy) obtained by the calculation based on the calculation formula Fy = C1-C2 + C3-C4 are shown. In an actual prototype, the capacitance value of each capacitive element is detected as a voltage value, and the result of addition / subtraction of the detected voltage value is used as each detection value. Therefore, the detection values V (Mx) and V (Fy) shown in the graph are used. ) Are values obtained as voltage values.

  As shown by the solid line graph in the figure, when the value of the applied moment Mx is increased or decreased, the detected value V (Mx) of the moment Mx also increases or decreases in proportion thereto. This indicates that a correct detection value is obtained for the moment Mx. However, as indicated by the broken line graph in the figure, the detected value V (Fy) of the force Fy also increases or decreases in proportion to the value of the applied moment Mx. Originally, when only the moment Mx is applied, the detection value V (Fy) of the force Fy must be maintained at zero. Eventually, in the detection operation described in §4, the component of moment Mx is included in the detection value of force Fy.

  Of course, the value of the detection value V (Fy) obtained when only the moment Mx is applied is actually smaller than the value of the detection value V (Fy) obtained when only the force Fy is applied. Therefore, if the detection value V (Fy) indicated by the broken line in FIG. 16 is handled as an error component related to the detection of the force Fy, there is no problem in an application that does not require strict detection. However, there is a problem in using it for an application that requires a highly accurate detection value in which the moment component and the force component are strictly distinguished. A similar problem occurs between the force Fx and the moment My. That is, in the detection operation described in §4, the component of the moment My is included in the detection value of the force Fx.

  The inventor of the present application sought the cause of the moment Mx component being included in the detected value of the force Fy, as shown in the broken line graph of FIG. As a result, it was found that the table shown in FIG. 14 is not strictly correct, and that the capacitance values of the capacitive elements C1 to C8 increase or decrease exactly as in the table shown in FIG. .

  In the table of FIG. 17, a column surrounded by a thick line is a difference from the table of FIG. 14. That is, the contents of the eight columns surrounded by bold lines are “0” in the table of FIG. 14, but are not strictly “0” but should be “+ δ” or “−δ”. is there. Here, first, the reason why the result of the fifth row (+ My row) of the table of FIG. 17 is obtained will be described.

  As described above, when the moment + My around the Y-axis acts on the force detection device of FIG. 10, the structure constituting the device is deformed as shown in FIG. As a result, a downward pressing force -fz is applied to the support substrate 300 from the columnar body T1, and an upward pulling force + fz is applied to the support substrate 300 from the columnar body T2. Therefore, the electrode interval between the capacitive elements C1 and C2 is reduced, the capacitance value is increased, the electrode interval between the capacitive elements C3 and C4 is increased, and the capacitance value is reduced. Therefore, as shown in the fifth row (+ My row) of the table of FIG. 17, the capacitance values of the capacitive elements C1 and C2 are “+ Δ”, and the capacitance values of the capacitive elements C3 and C4 are “−Δ”. "

  In the description of §4, at this time, the columnar bodies T3 and T4 are not inclined and are handled as those in which the capacitance values of the capacitive elements C5 to C8 do not change. As shown in FIG. 11, when a force + Fx is applied, all of the four columnar bodies T1 to T4 are inclined in the positive direction of the X axis, but when a moment My is applied as shown in FIG. This is because the columnar bodies T1 to T4 are not inclined, the columnar body T1 moves downward, the columnar body T2 moves upward, and the positions of the columnar bodies T3 and T4 do not change. Certainly, it is not an error to think in this way if the rough movements of the four columnar bodies T1 to T4 are captured.

  However, strictly speaking, when the moment + My around the Y axis acts, the columnar bodies T3 and T4 are slightly inclined in the positive direction of the X axis. Of course, since the inclination angle is smaller than the angle generated when the force + Fx as shown in FIG. 11 is applied, the change in the capacitance value is also small. In the table of FIG. 17, the symbol “δ” shown in the column surrounded by a thick line indicates “capacitance value change occurring in the main capacitor element”, similarly to the symbol “Δ” shown in the other columns. Although it is a code | symbol, it has shown that the variation | change_quantity of an electrostatic capacitance value is small. Hereinafter, the variation component indicated by the symbol “δ” is referred to as “other-axis interference component”.

  In the fifth row (+ My row) of the table of FIG. 17, “+ δ” is described in the columns of the capacitive elements C5 and C7, and “−δ” is described in the columns of the capacitive elements C6 and C8. Since the column bodies T3 and T4 are slightly tilted in the positive direction of the X axis due to the action of the moment + My around the Y axis, the electrode spacing of the capacitive elements C5 and C7 is slightly reduced, and the capacitance value is slightly It shows that the electrode distance between the capacitive elements C6 and C8 is slightly increased and the capacitance value is slightly decreased.

  Similarly, “+ δ” is described in the column of the capacitive elements C2 and C4 in the fourth row (+ Mx row) of the table of FIG. 17, and “−δ” is described in the columns of the capacitive elements C1 and C3. However, this is because the moments + Mx around the X axis act to cause the columnar bodies T1 and T2 to slightly tilt in the negative direction of the Y axis, so that the electrode spacing of the capacitive elements C1 and C3 slightly increases, and the capacitance value Shows a slight decrease, the electrode distance between the capacitive elements C2 and C4 is slightly reduced, and the capacitance value is slightly increased.

  As shown in the broken line graph of FIG. 16, the reason why the detected value of the force Fy includes the component of the moment Mx is based on the content of the fourth row (+ Mx row) of the table of FIG. This is because the calculation of Fy = C1-C2 + C3-C4 was performed. Also in the table of FIG. 17, the absolute value of “δ” described in the same row is equal because of the geometric symmetry of each electrode. Therefore, when the moment Mx is applied, Fy = C1−C2 + C3−C4 = −4δ. The detection value V (Fy) shown in the broken line graph of FIG. 16 is a detection value corresponding to this −4δ (other-axis interference component).

  Similarly, when the calculation Fx = C5-C6 + C7-C8 is performed based on the content of the fifth row (+ My row) of the table of FIG. 17, the absolute value of “δ” described in the same row is Since they are equal, Fx = + 4δ (interaxial interference component). This is the cause of the moment My component being included in the detected value of the force Fx.

<<< §6. Correction principle by sub-capacitance element >>
The main point of the present invention is to perform accurate detection with the interference of the other axis component eliminated by correcting the interference of the other axis component caused by the reason described in §5 by the sub-capacitance element. In other words, the other-axis interference component δ generated in the capacitance values of the main capacitive elements C1 to C8 for the reason described in §5 is offset by the change in the capacitance values of the sub-capacitance elements D1 to D8. It is in. Hereinafter, this correction principle will be described.

  FIG. 18 is an enlarged plan view of the 16 electrodes shown in FIG. As described above, the eight main fixed electrodes E1 to E8 are the electrodes constituting the eight main capacitive elements C1 to C8, and the eight sub fixed electrodes F1 to F8 are the eight sub capacitive elements D1. To D8. C1 to C8 and D1 to D8, which are shown in parentheses in the figure, are reference numerals indicating capacitive elements constituted by the respective electrodes.

  Here, the eight sub-capacitance elements D1 to D8 have a function of correcting the capacitance values of the eight main capacitance elements C1 to C8, respectively. That is, the sub-capacitance element D1 corresponds to the main capacitance element C1, the sub-capacitance element D2 corresponds to the main capacitance element C2, and so on. One sub-capacitance element corresponds to one main capacitance element. Each capacitive element is always handled in a state where the main and sub are paired. In FIG. 18, each of the fixed electrodes is shown with eight different types of hatching, but this is for the convenience of giving the same hatching to the electrodes constituting the pair and clarifying the correspondence. For example, the main fixed electrode E1 and the sub fixed electrode F1 are subjected to the same hatching. This is because the main capacitive element C1 constituted by the main fixed electrode E1 and the sub fixed electrode F1 are arranged. This indicates that the capacitive element D1 corresponds to form a pair.

  Now, in §5, regarding the eight main capacitive elements C1 to C8 constituted by the eight main fixed electrodes E1 to E8, the capacitance values when six types of force components are applied to the force receiving body 100 are shown. It has been explained that the exact change mode is as shown in the table of FIG. Therefore, here, for the eight sub-capacitance elements D1 to D8 constituted by the eight sub-fixed electrodes F1 to F8 shown in FIG. Let's consider what the exact change of the capacitance value will be.

  FIG. 19 shows the sub-capacitance elements D1 to D8 when the force components act on the force receiving body 100 in the force detection device shown in FIG. 10 (the symbols F1 to F8 in parentheses indicate the corresponding sub-fixed electrodes). It is a table which shows the aspect of a change of the electrostatic capacitance value of (). Here, a column surrounded by a thick line is a column in which the capacitance values of the sub-capacitance elements D1 to D8 change, and a symbol “ε” is a code indicating “a change in capacitance value generated in the sub-capacitance device”. . This code “ε” does not indicate a specific value, like the code “Δ” and the code “δ”. However, as shown in FIG. 9, when each fixed electrode takes a shape and arrangement having geometric symmetry with the X axis and Y axis as symmetry axes, “ε” in each column of the table of FIG. The value of “” is equal to the value of “ε” in any other column having the same geometric condition.

  First, let us consider changes in the capacitance values of the sub-capacitance elements D1 to D8 when a force + Fx in the X-axis positive direction is applied to the force receiving body 100. In this case, as shown in FIG. 11, each of the columnar bodies T1 to T4 is inclined in the right direction (X-axis positive direction) in the drawing (the deformation mode corresponding to FIG. 2 (b)). ). For this reason, in the lower end side thin portions 215, 225, 235, and 245 that function as common displacement electrodes, the right half portion in the drawing is displaced downward in the drawing, and the left half portion is moved upward in the drawing. Displace.

  Here, referring to the plan view of FIG. 18, it can be seen that the shapes of the sub-fixed electrodes F1 to F8 are all symmetrical. Accordingly, the distance between each of the sub-fixed electrodes F1 to F8 and the common displacement electrode located above the sub-fixed electrodes F1 to F8 is reduced in part (right half part), but is expanded in another part (left half part). Therefore, the capacitance value does not change in total. This is why each column of the first row (+ Fx row) of the table of FIG. 19 is “0”. Similarly, when the force in the negative X-axis direction -Fx is applied, each column is "0".

  On the other hand, when a force + Fy in the Y-axis positive direction is applied to the force receiving body 100, a phenomenon occurs in which the change mode when the force + Fx is applied is rotated by 90 ° when viewed from the top. Therefore, as shown in the second row (+ Fy row) of the table of FIG. 19, each column is also “0”. The same applies when a force -Fy in the Y-axis negative direction is applied.

  Further, when a force + Fz in the positive direction of the Z-axis is applied to the force receiving body 100, each of the columnar bodies T1 to T4 is pulled against the upper surface of the support substrate 300 as shown in FIG. Since a force is applied, the electrode interval between the capacitive elements D1 to D8 is widened, and the capacitance value is reduced. “−ε” shown in the third row (+ Fz row) of the table of FIG. 19 indicates such a decrease in the capacitance value. On the contrary, when the force −Fz in the negative Z-axis direction acts on the force receiving body 100, each of the columnar bodies T1 to T4 exerts a pressing force on the upper surface of the support substrate 300. The electrode interval between the capacitive elements D1 to D8 is narrowed, and the capacitance value is increased. Accordingly, each column of the third row (+ Fz row) of the table of FIG. 19 is “+ ε”.

  As described above, since “ε” does not indicate a specific eigenvalue, the values of “−ε” shown in the third row (+ Fz row) of the table of FIG. 19 are not necessarily the same. Not a value. As can be seen from the plan view of FIG. 18, the sub-fixed electrodes F1, F2, F5, and F8 are circular electrodes, whereas the sub-fixed electrodes F3, F4, F6, and F7 are annular electrodes. Are different in shape and area. Accordingly, the values of “−ε” shown in the columns D1, D2, D5, and D8 shown in the third row (+ Fz row) of the table of FIG. 19 are equal to each other, and each of D3, D4, D6, and D7 The values of “−ε” shown in the column are equal to each other, but the values are different between the former and the latter.

  Next, consider a case where a moment acts on the force receiving body 100. As shown in FIG. 13, when a positive moment + My around the Y axis acts on the force receiving member 100, a downward pressing force −fz is applied from the columnar body T1 to the support substrate 300, and the columnar shape. An upward pulling force + fz is applied to the support substrate 300 from the body T2. Therefore, referring to the plan view of FIG. 18, the electrode distance between the capacitive elements D6 and D8 is narrowed, and the capacitance value is increased. On the other hand, the electrode interval of the capacitive elements D5 and D7 is increased, and the capacitance value is decreased. “+ Ε” or “−ε” in the columns D5 to D8 in the fifth row (+ My row) of the table in FIG. 19 indicates such an increase or decrease in the capacitance value.

  In this way, when the positive moment + My around the Y axis acts, the columnar bodies T3, T4 are slightly inclined in the X axis positive direction. However, for the capacitive elements D1 to D4 arranged on the Y-axis, the electrode interval of a part (right half part) is reduced, but the electrode interval of another part (left half part) is widened. Then, the capacitance value does not change. This is why the columns D1 to D4 in the fifth row (+ My row) of the table of FIG. 19 are “0”. Conversely, when the negative moment -My around the Y axis acts, the relationship between the increase and decrease of the capacitance value is reversed, and the fifth row of the table of FIG. 19 shows “+” and “−”. The result of reversing is obtained.

  Further, when a positive moment + Mx around the X axis is applied to the force receiving member 100, a phenomenon occurs in which the change mode when the above-described moment + My is applied is rotated by 90 ° when viewed from the top. That is, a downward pressing force −fz is applied to the support substrate 300 from the columnar body T4, and an upward pulling force + fz is applied to the support substrate 300 from the columnar body T3. Therefore, the electrode interval between the capacitive elements D1 and D3 is narrowed, and the capacitance value is increased. On the other hand, the electrode distance between the capacitive elements D2 and D4 is increased, and the capacitance value is decreased. “+ Ε” or “−ε” in the columns D1 to D4 in the fourth row (+ Mx row) of the table in FIG. 19 indicates such an increase or decrease in the capacitance value.

  Thus, when the positive moment + Mx around the X-axis acts, the columnar bodies T1 and T2 are slightly inclined in the negative Y-axis direction. However, regarding the capacitive elements D5 to D8 arranged on the X axis, the electrode interval of a part (upper half part in FIG. 18) is widened, but another part (lower half part in FIG. 18) Since the electrode interval is reduced, the capacitance value does not change in total. This is why the columns D5 to D8 in the fourth row (+ Mx row) of the table of FIG. 19 are “0”. On the contrary, when a negative moment -Mx around the X axis is applied, the relationship between the increase and decrease of the capacitance value is reversed, and the fourth line of the table of FIG. The result of reversing is obtained.

  Finally, let us consider a case where a moment Mz around the Z-axis acts on the force receiving body 100. When a positive moment + Mz or negative moment -Mz around the Z-axis is applied to the force receiving body 100, the four columnar bodies T1 to T4 are inclined in any one of up, down, left, and right in FIG. However, even if it is tilted in any direction, the electrode spacing of the capacitive elements D1 to D8 is partially expanded and the other part is contracted, so that the capacitance value does not change in total. This is why the columns D1 to D8 in the sixth row (+ Mz row) of the table of FIG. 19 are “0”.

  After all, in the force detection device shown in FIG. 10, when each force component acts on the force receiving body 100, the capacitance values of the main capacitive elements C1 to C8 change as shown in the table of FIG. It can be seen that the capacitance values of the elements D1 to D8 change as shown in the table of FIG. Here, the columns C1 to C4 and D1 to D4 in the fourth row (+ Mx row) and the columns C5 to C8 and D5 to D8 in the fifth row (+ My row) of both tables are mutually connected. It can be seen that the codes are complementary. That is, when the former is “−δ”, the latter is “+ ε”, and when the former is “+ δ”, the latter is “−ε”. This means that the former ± δ can be canceled by the latter ± ε.

  The absolute value of the value ± δ shown in the table of FIG. 17 (of course, the absolute value of ± Δ) is an amount that depends on the configuration of the main capacitive elements C1 to C8. Specifically, the absolute value δ increases as the electrode interval between the pair of electrodes constituting each main capacitive element (the electrode interval when no force is applied) is set smaller. The larger the area of the pair of electrodes, the larger the absolute value δ. Similarly, the absolute value of the value ± ε shown in the table of FIG. 19 is an amount that depends on the configuration of the sub-capacitance elements D1 to D8. Specifically, the absolute value ε increases as the electrode distance between the pair of electrodes constituting each sub-capacitance element (the electrode distance when no force is applied) is set smaller. The larger the area of the pair of electrodes, the larger the absolute value ε.

  Therefore, if the configurations of the main capacitive elements C1 to C8 and the configurations of the sub-capacitance elements D1 to D8 are properly set, the other-axis interference component ± δ in the table of FIG. 17 is canceled by ± ε in the table of FIG. Can do. This is the correction principle by the sub-capacitance element, which is a feature of the present invention.

  This correction principle will be described with reference to the table of FIG. The table shown in FIG. 20 includes the columns indicating the change in capacitance value for the eight main capacitive elements C1 to C8 shown in FIG. 17, and the eight sub-capacitance elements D1 to D8 shown in FIG. It is a table which shows the sum with each column which shows the aspect of the change of the electrostatic capacitance value about. Here, the column surrounded by a thick line is a column in which the capacitance values of the sub-capacitance elements D1 to D8 change. In other words, in FIG. 20, each column other than the column surrounded by a bold line has exactly the same contents as the table in FIG.

  Now, let us assume that the absolute value δ and the absolute value ε in each column are equal in the table of FIG. As already stated, “δ” and “ε” in this table do not indicate specific eigenvalues and are not necessarily the same value, but for each individual column, δ = If ε holds, the column described as “−δ + ε” or “+ δ−ε” can be replaced with “0”. That is, all four columns on the left side of the fourth row (+ Mx row) of the table of FIG. 20 are “0”, and all four columns on the right side of the fifth row (+ My row) are “0”. .

  After all, the table of FIG. 20 is equivalent to the table of FIG. 14 except for the third row (+ Fz row). For each column in the third row, “−Δ” in the table of FIG. 14 is replaced with “− (Δ + ε)” in the table of FIG. 20, but this changes slightly in absolute value. Only. That is, the scaling factor of the detected value of the force Fz is only slightly changed, and essentially no trouble occurs.

  Then, instead of the arithmetic expression shown in FIG. 15 using the capacitance values of the eight main capacitive elements C1 to C8 (shown using the same reference numerals C1 to C8), the eight sub capacitive elements D1 to D1 are further provided. The six force components Fx, Fy, Fz, Mx, My, and Mz can be detected by using the arithmetic expression shown in FIG. 21 using the capacitance value of D8 (shown by using the same symbols D1 to D8). It turns out that it becomes. In addition, when the arithmetic expression shown in FIG. 21 is used, the other-axis interference component ± δ described in §5 is offset by the change ± ε occurring in the sub-capacitance elements D1 to D8, so that force and moment are strictly Thus, an accurate detection value can be obtained.

  Specifically, according to the equation of FIG. 21, the force Fx is obtained by the equation Fx = (C5 + D5) − (C6 + D6) + (C7 + D7) − (C8 + D8), and the force Fy is Fy = (C1 + D1) −. (C2 + D2) + (C3 + D3) − (C4 + D4). The moment Mz is obtained by the following formula: Mz = (C1 + D1) − (C2 + D2) − (C3 + D3) + (C4 + D4) − (C5 + D5) + (C6 + D6) + (C7 + D7) − (C8 + D8). The reason is that the contents of the first row (+ Fx row), the second row (+ Fy row), and the sixth row (+ Mz row) of the table of FIG. 20 are the contents of each row of the table of FIG. Will no longer require explanation.

  On the other hand, according to the equation of FIG. 21, the force Fz is Fz = − ((C1 + D1) + (C2 + D2) + (C3 + D3) + (C4 + D4) + (C5 + D5) + (C6 + D6) + (C7 + D7) + (C8 + D8)) Is obtained by the following formula. The value of the force Fz obtained by the formula of Fz shown in FIG. 15 is given as the sum “−8Δ” of the contents of the eight columns in the third row of the table of FIG. The value of the force Fz obtained by the formula of Fz is given as the sum “−8 (Δ + ε)” of the contents of the eight columns in the third row of the table of FIG. The difference between “−8Δ” and “−8 (Δ + ε)” is merely a problem of scaling of the detected value, and thus there is no practical problem.

  The force Fz is expressed by the following formula: Fz = − ((C1 + D1) + (C2 + D2) + (C3 + D3) + (C4 + D4)), Fz = − ((C5 + D5) + (C6 + D6) + (C7 + D7) + (C8 + D8)) It is also possible to obtain by the following formula. However, in practice, Fz = − ((C1 + D1) + (C2 + D2) + (C3 + D3) + (C4 + D4) + (C5 + D5) + (C6 + D6) + (C7 + D7) + (C7 + D7) + ( C8 + D8)) is preferable.

  On the other hand, according to the equation of FIG. 21, the moment Mx is obtained by the equation Mx = − (C5 + D5) − (C6 + D6) + (C7 + D7) + (C8 + D8), and the moment My is My = (C1 + D1) + (C2 + D2). )-(C3 + D3)-(C4 + D4). The reason for this is that, as described above, assuming that the absolute value δ and the absolute value ε in each column are equal, all four columns on the left side of the fourth row (+ Mx row) of the table of FIG. , And the four columns on the right side of the fifth row (+ My row) are all “0”, and the contents of the fourth and fifth rows of the table of FIG. This is because the contents are the same as those in the fourth and fifth lines.

<<< §7. Capacitance element design method >>
In the table of FIG. 20, in order to make the absolute value δ and the absolute value ε in each column equal, the configuration of the i-th (i = 1 to 8) main capacitive element Ci and corresponding to this It is only necessary to set the configuration of the i-th sub-capacitance element Di well. As described above, the capacitance value of the capacitive element can be adjusted by changing the electrode interval and the electrode area of the pair of electrodes constituting the capacitive element. However, in the case of the structure as shown in FIG. 10, it is easier to adjust the capacitance value of the capacitive element by adopting an adjustment method that changes the electrode area than an adjustment method that changes the inter-electrode distance. It is.

  Therefore, when designing the force detection device according to the present invention, in practice, first, after determining the shape, size, and arrangement of the eight main fixed electrodes E1 to E8, the main fixed electrodes E1 to E8 are configured. Eight sub-fixed electrodes F1 constituting the sub-capacitance elements D1 to D8 from which the change amounts .epsilon. Of the capacitance value for canceling the other-axis interference components. ± ..delta. It is preferable to adopt a design method of determining the shape, size, and arrangement of F8.

  For example, as shown in FIG. 18, the shapes, sizes, and arrangements of the four main fixed electrodes E1 to E4 provided in the vicinity of the lower ends of the first columnar body 11 and the second columnar body 12 are as illustrated. Let it be decided. In this case, the four sub-fixed electrodes F1 to F4, when only the moment Mx is applied, have a change in capacitance value that occurs in the main capacitance elements C1 to C4 and an absolute value that is equal and opposite in sign. Is defined as an electrode having a shape, size, and arrangement suitable for forming the sub-capacitance elements D1 to D4. Similarly, when the shapes, sizes, and arrangements of the four main fixed electrodes E5 to E8 provided in the vicinity of the lower ends of the third columnar body 13 and the fourth columnar body 14 are determined as illustrated, 4 The sub-fixed electrodes F5 to F8, when only the moment My is applied, can obtain a change in which the absolute value is the same as the change in the capacitance value generated in the main capacitance elements C5 to C8 and the change is opposite in sign. It is defined as an electrode having a shape, size, and arrangement suitable for constituting the capacitive elements D5 to D8.

  FIG. 22 is a side cross-sectional view showing an example of an experimental method for determining the shape, size, and arrangement of the sub-fixed electrodes F1 to F8. In the illustrated apparatus, a measuring jig 400 is attached to the apparatus main body shown in FIG. 10 actually manufactured as a prototype. As shown in the figure, the measuring jig 400 includes a connection portion 410, an upper lid portion 420, a side wall portion 430, and a flange portion 440, and constitutes a cover that covers the upper half of the apparatus body. The reason why the experiment is performed with the measurement jig 400 attached is to apply an accurate moment to the force receiving body 100.

  As described above, in the embodiment described here, the XYZ three-dimensional coordinate system is positioned so that the XY plane is in the vicinity of the upper surface of the support substrate 300 and parallel to the upper surface of the support substrate 300, and The Z axis, which is positive and negative in the lower side, is defined so as to pass through the substantially central position of the upper surface of the support substrate 300. More precisely, the XYZ three-dimensional coordinate system is defined so that the XY plane is sandwiched between the four lower thin portions 215, 225, 235, 245 and the upper surface of the support substrate 300. Yes. As described in §3, the present inventor believes that it is most preferable to set the position of the XY plane of the XYZ three-dimensional coordinate system to the center position between the pair of electrodes constituting the capacitive element. Because. For this reason, the following experiment will be described by taking as an example a case where the origin O is defined at such a position.

  However, as already described, the origin O is a conceptual position and does not necessarily need to be strictly defined. Actually, if it is defined at a predetermined point near the upper surface near the center of the support substrate 300, the effect of the present invention can be obtained sufficiently in practice. Therefore, for example, an XYZ three-dimensional coordinate system in which the upper surface of the support substrate 300 is the XY plane may be defined. In this case, the obtained force detection device is a device having a function of accurately detecting six-component forces relating to each coordinate axis in such an XYZ three-dimensional coordinate system.

  Now, when the measurement jig 400 as shown in FIG. 22 is used, the forces Fx, Fy, Fz in the respective axial directions of the XYZ three-dimensional coordinate system and the moments Mx, My around the respective axes in the XYZ three-dimensional coordinate system. , Mz can be operated accurately. For example, if a wire is attached to the action point P1 at the right end of the flange portion 440 in the drawing and pulled horizontally in the right direction in the drawing, the force component + Fx can be applied. On the contrary, if a wire is attached to the action point P2 at the left end of the flange portion 440 and pulled horizontally in the left direction in the figure, the force component -Fx can be applied. On the other hand, when the force components + Fy and −Fy in the Y-axis direction are applied, an action point on the near side or the far side of the flange portion 440 that is not illustrated may be used. Since these action points are located at positions on the XY plane, the applied force components become accurate force components in the X-axis or Y-axis direction.

  In addition, if a wire is attached to the action point P3 located at the center of the upper lid part 420 and pulled vertically upward in the figure, the force component + Fz can be applied. The force component -Fz can be applied by pushing it down vertically. Of course, the forces Fx, Fy, and Fz can be applied using a plurality of action points. In this case, a plurality of action points may be set at positions having symmetry with respect to the coordinate axes.

  On the other hand, in order to apply moments Mx, My, Mz around each axis to the force receiving body 100, complementary forces (couples) may be applied to two action points having symmetry with respect to the coordinate axes. For example, in order to apply a positive moment + My around the Y axis, the wire attached to the action point P1 is pulled vertically downward in the figure, and the wire attached to the action point P2 is pulled vertically upward in the figure. What is necessary is just to make the absolute value of the force which pulls a wire equal. Of course, in this case, the illustrated dimensions r1 and r2 (distances from the origin O to the action points P1 and P2) must be equal to each other. If the direction in which the wire is pulled is interchanged between the left and right, a negative moment -My around the Y axis can be applied.

  Similarly, when the moments + Mx and -Mx around the X axis are applied, a point of action on the front side or the back side of the flange portion 440 (not shown) is used, and one of them is complementarily drawn upward and the other downward. You just need to add power. In addition, when a positive moment + Mz around the Z axis is applied, the wire attached to the action point P1 is pulled in the back direction in the drawing along the XY plane, and the wire attached to the action point P2 is taken along the XY plane. What is necessary is just to pull in the near direction of a figure, and when applying the negative moment -Mz around a Z-axis, the direction which pulls a wire should be replaced with right and left.

  Using such a measurement jig 400, for example, a prototype including eight main fixed electrodes E1 to E8 and eight sub fixed electrodes as shown in FIG. When Mx is applied, the capacitance value change generated in each main capacitive element is compared with the capacitance value change generated in each sub-capacitance element, and the area of each electrode is adjusted so that the absolute values of both are equal. Good. For example, when a moment + Mx having a predetermined magnitude is applied, a change in capacitance value generated in the main capacitive element C1 is −δ, and a change in capacitance value generated in the sub-capacitance element D1 is + ε. , Δ> ε, correction may be made to increase the area of the sub-fixed electrode F1 until δ = ε. By performing trial and error using such a prototype, it is possible to design a main capacitor element and a sub capacitor element that satisfy δ = ε with practical accuracy.

  As described above, the method for designing the fixed electrodes constituting the main capacitive element and the sub-capacitance element by actual measurement using a prototype has been described. However, it is also possible to perform design by computer simulation instead of actual measurement. For example, if a known computer analysis method such as the finite element method is used, a result equivalent to actual measurement can be obtained by simulation on a computer instead of creating a prototype having a physical entity. That is, if the dimensions and physical constants of each part of the structure shown in FIG. 10 are given to the computer as parameters, a deformation mode when a moment + Mx having a predetermined magnitude is applied to the force receiving member is simulated, and each capacity is simulated. A change in the capacitance value generated in the element can be obtained by calculation. Practically, first, after designing the fixed electrodes constituting the main capacitor element and the sub-capacitor element by such computer simulation, verification with a prototype may be performed as necessary.

<<< §8. Simplification of detection circuit >>
The detection circuit used in the device according to the present invention has a function of detecting a predetermined direction component of the force acting on the force receiving body by using each arithmetic expression of FIG. 21 based on the capacitance value of each capacitive element. have. Each arithmetic expression in FIG. 21 is configured by adding or subtracting a term (Ci + Di) (where i = 1 to 8), and each term is a capacitance value of the i-th main capacitive element. It is the sum of Ci and the capacitance value Di of the i-th sub-capacitance element. Such a calculation for calculating the sum of numerical values can be performed using an analog adder or a digital calculator, but focusing on the physical property of “sum of capacitance values” The sum can be obtained by a simple method of “electrical parallel connection” without using a special arithmetic unit.

  For example, when it is necessary to obtain the sum of capacitance values “Csum = Ca + Cb” for two capacitance elements Ca and Cb, the individual capacitance values Ca and Cb are detected as analog values or digital values. Csum can be obtained by an arithmetic operation using an analog adder or a digital arithmetic unit. However, if one electrode of the two capacitive elements Ca and Cb is connected by wiring and the other electrode is also connected by wiring, and the two are connected in parallel, the capacitive element Cab connected in parallel is connected. Is equal to the sum “Csum = Ca + Cb” of the individual capacitance values Ca and Cb.

  Based on such a policy, for a plurality of capacitive elements for which the sum of capacitance values is to be calculated, the sum in the detection circuit 30 is calculated by providing wirings that are electrically connected to each other. It is possible to omit the operation to be performed. When practicing the present invention, it is extremely preferable to practically connect the i-th (where i = 1 to 8) main capacitor element and the i-th sub-capacitor element in parallel.

  Specifically, the wiring for connecting the first main capacitive element C1 and the first sub-capacitance element D1 in parallel to each other, and the second main capacitive element C2 and the second sub-capacitance element D2 are mutually connected. , A wiring for connecting the third main capacitance element C3 and the third subcapacitance element D3 in parallel to each other, a fourth main capacitance element C4 and a fourth subcapacitance element A wiring for connecting D4 in parallel with each other, a wiring for connecting the fifth main capacitive element C5 and the fifth sub-capacitance element D5 in parallel with each other, a sixth main capacitive element C6 and a sixth Wiring for connecting the sub-capacitance element D6 in parallel with each other, wiring for connecting the seventh main capacitance element C7 and the seventh sub-capacitance element D7 in parallel with each other, and an eighth main capacitance element Wiring for connecting C8 and the eighth sub-capacitance element D8 in parallel with each other may be provided.

  Then, when the detection circuit detects the predetermined direction component of the force acting on the force receiving body by using each arithmetic expression of FIG. 21, the first main capacitive element C1 and the first sub capacitive element The combined capacitance element constituted by parallel connection with D1 is used as the value of “C1 + D1”, and the combined capacitance element constituted by parallel connection of the second main capacitive element C2 and the second auxiliary capacitive element D2 The electrostatic capacitance value of the capacitive element is used as the value of “C2 + D2”, and the electrostatic capacitance value of the combined capacitive element configured by parallel connection of the third main capacitive element C3 and the third sub capacitive element D3 is “C3 + D3”. As the value of “C4 + D4”, and the capacitance value of the combined capacitive element constituted by the parallel connection of the fourth main capacitive element C4 and the fourth sub-capacitor element D4 is used as the fifth main capacitive element C4. Parallel connection of capacitive element C5 and fifth sub-capacitance element D5 The capacitance value of the combined capacitance element configured as described above is used as the value of “C5 + D5”, and the capacitance of the combined capacitance element configured by parallel connection of the sixth main capacitance element C6 and the sixth sub capacitance element D6. The capacitance value is used as the value of “C6 + D6”, and the capacitance value of the combined capacitance element configured by parallel connection of the seventh main capacitance element C7 and the seventh sub capacitance element D7 is used as the value of “C7 + D7”. Since the capacitance value of the combined capacitance element formed by parallel connection of the eighth main capacitance element C8 and the eighth sub capacitance element D8 can be used as the value of “C8 + D8”, the sum of these values is obtained. Calculation can be omitted.

  In the case of the embodiment shown in FIG. 10, if the intermediate body 200 is made of a conductive material such as metal, the lower end side thin portions 215, 225, 235, and 245 function as a common displacement electrode having conductivity. All of the displacement electrodes of the 16 capacitive elements are electrically connected through the intermediate body 200. Therefore, in order to connect the pair of main and sub-capacitance elements in parallel, the main fixed electrodes E1 to E8 and the sub fixed electrodes F1 to F8 formed on the support substrate 300 side are wired as shown in the plan view of FIG. Can be applied.

  In the example shown in FIG. 23, on the upper surface of the support substrate 300, between the electrodes E1 / F1, between the electrodes E2 / F2, between the electrodes E3 / F3, between the electrodes E4 / F4, between the electrodes E5 / F5, between the electrodes E6 / F6, Wiring for connecting the electrodes E7 / F7 and between the electrodes E8 / F8 is made, and wiring to the bonding pads B1 to B8 is also made for each of the electrodes E1 to E8. Therefore, for example, if a circuit for detecting the capacitance value between the bonding pad B1 and the intermediate body 200 is provided, the capacitance value “C1 + D1” can be obtained.

  In the example shown in FIG. 23, notches are provided in part of the annular sub-fixed electrodes F3, F4, F7, and F8 in order to pass wiring on the support substrate 300. However, the width of the notches If is set to be small, the substantial geometric symmetry is not greatly affected. Of course, a through hole may be formed in the support substrate 300 without providing a notch, and wiring may be performed on the back surface side.

<<< §9. Other variations >>
So far, the present invention has been described in terms of basic embodiments. In the first place, the basic idea of the present invention is that in the force detection device described in the above-mentioned Patent Document 3 (Japanese Patent Laid-Open No. 2008-096229), the moment Mx is a detected value of the force Fy as shown in the graph of FIG. It is made for the purpose of correcting the phenomenon that the moment My interferes with the detected value of the force Fx as the other axis component.

  In order to achieve the above object, in the present invention, four sub-capacitance elements D1 to D4 are provided for the four main capacitance elements C1 to C4 used for detecting the force Fy, respectively, and the main capacitance element C1 is obtained by the action of the moment Mx. The other-axis interference component δ (fourth row of the table of FIG. 17) generated in .about.C4 is canceled by the component ε (fourth row of the table of FIG. 19) generated in the sub-capacitance elements D1 to D4 by the action of the same moment Mx. Take the configuration. For the four main capacitive elements C5 to C8 used for detecting the force Fx, four sub-capacitance elements D5 to D8 are provided, respectively, and the other-axis interference component δ generated in the main capacitive elements C5 to C8 by the action of the moment My. A configuration is adopted in which (the fifth row of the table of FIG. 17) is canceled by the component ε (the fifth row of the table of FIG. 19) generated in the sub-capacitance elements D5 to D8 by the action of the same moment My.

  Thus, the essential feature of the present invention is that the other-axis interference component δ generated in the detection value of the main capacitive element is canceled by the capacitance value ε of the sub-capacitance element. Therefore, the present invention can be implemented in various modifications without departing from the above idea. Hereinafter, some modified examples of the present invention will be described.

<9-1: Configuration of columnar body>
The force detection device according to the present invention is based on the premise that the force receiving body 100 and the support substrate 300 are connected by the four columnar bodies T1 to T4. In addition, the four columnar bodies T1 to T4 are arranged so that their central axes are parallel to the Z axis, and the first columnar body T1 is a positive portion whose central axis is the X axis. The second columnar body T2 is disposed at a position where the central axis intersects the negative portion of the X axis, and the third columnar body T3 is disposed at a position where the central axis is positive of the Y axis. 4th columnar body T4 is arrange | positioned in the position which the center axis | shaft cross | intersects the negative part of a Y-axis.

  The reason for adopting such an arrangement is to provide a sensor in the vicinity of the lower end of each columnar body T1 to T4 to detect the inclination of the columnar body in a predetermined axis direction and the force applied from the columnar body onto each coordinate axis. It is. Therefore, in implementing the present invention, the shape and size of the four columnar bodies are matters that can be arbitrarily determined in design.

  However, in practice, the four columnar bodies are configured by structures of the same shape and the same size, and the arrangement pattern of these four columnar bodies is plane-symmetric with respect to both the XZ plane and the YZ plane. It is preferable to make it. As will be described later, in carrying out the present invention, the shape and arrangement of the main capacitive element and the sub-capacitance element, as well as the variation characteristics of the capacitance value related to the displacement of the force receiving body, also show geometric symmetry. It is preferable to make a simple design. For this purpose, it is preferable to design the four columnar bodies so as to have the same shape and the same size and to give symmetry to the arrangement.

<9-2: Arrangement of main capacitive element>
The force detection device according to the present invention is based on the premise that four main capacitive elements C1 to C4 are used for detecting the force Fy. Here, the first main capacitive element C1 is arranged in the first quadrant of the XY coordinate system, the second main capacitive element C2 is arranged in the fourth quadrant of the XY coordinate system, and the third main capacitive element C3. Are arranged in the second quadrant of the XY coordinate system, and the fourth main capacitive element C4 needs to be arranged in the third quadrant of the XY coordinate system. Further, when detecting the force Fx in addition to the detection of the force Fy, it is necessary to add four more main capacitive elements C5 to C8. In this case, the fifth main capacitive element C5 is arranged in the first quadrant of the XY coordinate system, the sixth main capacitive element C6 is arranged in the second quadrant of the XY coordinate system, and the seventh main capacitive element C7. Are arranged in the fourth quadrant of the XY coordinate system, and the eighth main capacitive element C8 needs to be arranged in the third quadrant of the XY coordinate system.

  If the main capacitive element is arranged so as to satisfy the above-described conditions, in principle, the force Fy or the force Fx can be detected. However, if the shape of each main capacitive element is disjoint and there is no symmetry in its arrangement, the force detection sensitivity will be different for each capacitive element. In the arithmetic expression of 21, it is necessary to take measures such as multiplying each capacitance value by a correction coefficient for performing sensitivity correction as necessary.

  Therefore, practically, four electrodes E1 to E4 on the support substrate side constituting the four main capacitance elements C1 to C4, or eight on the support substrate side constituting the eight main capacitance elements C1 to C8. The electrodes E1 to E8 are preferably composed of electrodes having the same shape and the same size, and the arrangement pattern of the plurality of electrodes is preferably symmetrical with respect to both the XZ plane and the YZ plane. .

  In particular, in the case of the basic embodiment described so far, as shown in the plan view of FIG. 18, two sheets on the supporting substrate side constituting the first main capacitive element C1 and the second main capacitive element C2 are provided. The electrode is obtained by cutting a first annular band (in the case of FIG. 18, an annular band such as a washer) disposed around the central axis of the first columnar body T1 along the X axis. The two electrodes E1 and E2 obtained and the two electrodes on the support substrate side constituting the third main capacitive element C3 and the fourth main capacitive element C4 are the central axis of the second columnar body T2. Is formed by two electrodes E3 and E4 obtained by cutting the second annular band disposed around the X axis along the X axis. Further, the two electrodes on the support substrate side constituting the fifth main capacitive element C5 and the sixth main capacitive element C6 are in a third annular shape arranged around the central axis of the third columnar body T3. The two electrodes E5 and E6 obtained by cutting the band along the Y-axis, and the two electrodes on the support substrate side constituting the seventh main capacitive element C7 and the eighth main capacitive element C8 are The fourth columnar body T4 includes two electrodes E7 and E8 obtained by cutting the fourth annular band disposed around the central axis along the Y axis.

  In this way, the two electrodes on the support substrate side constituting the pair of main capacitive elements included in the i-th sensor that detects the movement of the i-th (i = 1 to 4) columnar body Ti are It is a preferred embodiment of the present invention that the annular band disposed around the central axis of the columnar body Ti is constituted by two electrodes obtained by cutting along the X axis or the Y axis.

  The first reason is that a space for forming two electrodes on the support substrate side constituting the sub-capacitance element is secured in the inner region surrounded by the annular band. In the case of the example shown in FIG. 18, the two electrodes F6 and F8 on the support substrate side constituting the sixth sub-capacitance element D6 and the eighth sub-capacitance element D8 are the first electrodes constituted by the electrodes E1 and E2. The two electrodes F5 and F7 on the support substrate side which are arranged in the inner region surrounded by the annular band and constitute the fifth subcapacitance element D5 and the seventh subcapacitance element D7 are constituted by electrodes E3 and E4. It is arrange | positioned in the inner side area | region enclosed by the 2nd annular belt. Further, the two electrodes F2 and F4 on the support substrate side constituting the second subcapacitance element D2 and the fourth subcapacitance element D4 are surrounded by a third annular band constituted by the electrodes E5 and E6. Two electrodes F1 and F3 on the support substrate side which are arranged in the inner region and constitute the first subcapacitance element D1 and the third subcapacitance element D3 are a fourth annular band constituted by electrodes E7 and E8. It is arranged in the inner area surrounded by. In this way, if the main fixed electrodes E1 to E8 are constituted by one of the annular bands cut into two, the sub fixed electrodes F1 to F8 are arranged using the space in the inner part of the annular band. Can do.

  The second reason that the main fixed electrodes E1 to E8 are preferably constituted by one of the annular bands is that the detection sensitivity of the main capacitive elements C1 to C8 can be increased. The main capacitive elements C1 to C8 are components that play the main role of force detection in the force detection device according to the present invention, and it is preferable to obtain as high detection sensitivity as possible. When the main fixed electrodes E1 to E8 are configured by an annular band as illustrated in FIG. 18, a large change in the inter-electrode distance of the capacitive element when the columnar body is inclined can be taken. The sensitivity of the detection value obtained can be increased.

  In the case of the basic embodiment described so far, each of the columnar bodies T1 to T4 is formed of a cylindrical structure, and each of the lower end side thin portions 215, 225, 235, and 245 is formed of a disk-shaped structure. It is most efficient to make the annular band an annular structure (washer-like structure).

<9-3: Configuration of sub-capacitance element>
Subsequently, variations in the configuration of the sub-capacitance elements D1 to D8, more specifically, variations in the shape and arrangement of the eight sub-fixed electrodes F1 to F8 will be described.

  The force detection device according to the basic embodiment described so far detects six force components based on the capacitance values of a total of 16 main and sub-capacitance elements, using the arithmetic expression shown in FIG. It has a function. Here, the 16 capacitive elements are distributed to 4 sensors. That is, the first sensor includes the first main capacitive element C1 located in the first quadrant of the XY coordinate system, the second main capacitive element C2 located in the fourth quadrant of the XY coordinate system, and the sixth sub-capacitor. The second sensor has a capacitive element D6 and an eighth sub-capacitance element D8, and the second sensor includes a third main capacitive element C3 located in the second quadrant of the XY coordinate system and a third quadrant of the XY coordinate system. 4th main capacitive element C4, 5th subcapacitance element D5, and 7th subcapacitance element D7, and a 3rd sensor is located in the 1st quadrant of XY coordinate system A fifth main capacitor C5, a sixth main capacitor C6 located in the second quadrant of the XY coordinate system, a second subcapacitor D2, and a fourth subcapacitor D4. The fourth sensor includes a seventh main capacitive element C7 located in the fourth quadrant of the XY coordinate system and an eighth main capacitive element located in the third quadrant of the XY coordinate system. 8 has a first sub-capacitor element D1, and the third sub-capacitance element D3, the.

  Here, the shape and arrangement of the sub-capacitance elements D1 to D8 will be described in more detail. In the example shown in FIG. 18, the sub-fixed electrodes F3, F4, F6, and F7 are annular (washer-shaped) electrodes. The sub-fixed electrodes F1, F2, F8, and F5 are disk-shaped electrodes disposed on the inner side. In addition, all are arranged around the central axis of each columnar body. As described above, the sub capacitance elements D1 to D8 constituted by the sub fixed electrodes F1 to F8 having such shapes and arrangements have the capacitance value changes as shown in the table of FIG. It is. Then, by combining with the main capacitive elements C1 to C8, a change mode of the capacitance value as shown in the table of FIG. 20 is obtained, and six force components can be detected based on the arithmetic expression shown in FIG. It is as already described. However, in carrying out the present invention, the shape and arrangement of the sub-capacitance elements D1 to D8 are not limited to the basic embodiment shown in FIG.

  For example, in FIG. 18, even if the auxiliary fixed electrodes F3, F4, F6, and F7 and the auxiliary fixed electrodes F1, F2, F8, and F5 are completely replaced, detection of six force components is performed based on the arithmetic expression shown in FIG. Is possible. In short, one of the two electrodes on the support substrate side constituting the sixth and eighth sub-capacitance elements is constituted by an electrode having an annular shape, and the other is constituted by an electrode disposed in the inner region. Of the two electrodes on the support substrate side constituting the fifth and seventh sub-capacitance elements, one is constituted by an electrode having an annular shape, and the other is constituted by an electrode disposed in the inner region thereof, Of the two electrodes on the support substrate side constituting the second and fourth sub-capacitance elements, one is constituted by an electrode having an annular shape, and the other is constituted by an electrode disposed in the inner region, If one of the two electrodes on the support substrate side constituting the first and third sub-capacitance elements is constituted by an electrode having an annular shape, and the other is constituted by an electrode arranged in the inner region thereof, FIG. Basic facts shown in Fig. 18. It is possible to detect the six force components on the same principle as Embodiment.

  On the other hand, FIG. 24 is an enlarged plan view showing a first modification of the 16 electrodes shown in FIG. 18 (the shape and arrangement of the eight electrodes F1 to F8 constituting the sub-capacitance element are different). is there. In this modification, a disk in which the two electrodes on the support substrate side constituting the sixth and eighth sub-capacitance elements are arranged around the central axis of the first columnar body T1 is arranged along the X axis. The two semicircular electrodes F6 and F8 obtained by cutting and the two electrodes on the support substrate side constituting the fifth and seventh sub-capacitance elements are the central axis of the second columnar body T2. Is formed by two semicircular electrodes F5 and F7 obtained by cutting the disc disposed along the X-axis, and 2 on the support substrate side constituting the second and fourth sub-capacitance elements. The two electrodes are constituted by two semicircular electrodes F2 and F4 obtained by cutting a disk disposed around the central axis of the third columnar body T3 along the Y axis, The two electrodes on the support substrate side constituting the third sub-capacitance element are the central axes of the fourth columnar body T4. The placed disc around, is formed by two semicircular electrodes F1, F3 obtained by cutting along the Y axis. Here, the electrodes F1 to F8 are all semicircular electrodes having the same shape and the same size.

  In the sub-capacitance elements D1 to D8 constituted by the sub-fixed electrodes F1 to F8 having the shape and arrangement as shown in FIG. 24, the capacitance value changes as shown in the table of FIG. When the table of FIG. 25 is compared with the table of FIG. 19, there are fluctuations ± ε in more columns. As described above, this symbol “ε” is a symbol indicating “a change in capacitance value generated in the sub-capacitance element” and does not indicate a specific eigenvalue.

  The reason why the variation ± ε is generated in more columns in the table of FIG. 25 is that the sub-fixed electrodes F1 to F8 shown in FIG. 24 have a semicircular shape. Since the sub-fixed electrodes F1 to F8 shown in FIG. 18 are circular or annular electrodes arranged around the central axis of the columnar body, when the columnar body is inclined, the static capacitance of each subcapacitance element D1 to D8 is determined. Although the fluctuation of the capacitance value is “0”, in the case of the sub-capacitance elements D1 to D8 using the semicircular sub-fixed electrodes F1 to F8 shown in FIG. 24, an inclination in the X-axis or Y-axis direction is detected. Will be.

  As described above, in the modification example shown in FIG. 24, although the fluctuation amount ± ε for detecting the inclination of the columnar body is generated in the sub-capacitance elements D1 to D8, based on the respective arithmetic expressions shown in FIG. One force component can still be detected. That is, the electrodes F1 to F8 are all semicircular electrodes having the same shape and size, and the pair of electrodes are arranged so as to have symmetry with respect to the predetermined axis. The absolute values of ε described in the row of are equal to each other, the absolute values of ε described in the row of + Fy are equal to each other, the absolute values of ε described in the row of + Fz are equal to each other, The absolute values of ε described in the + Mz line are equal to each other. The absolute values of ε described in the columns D1 to D4 of the + Mx row are equal to each other, the absolute values of ε described in the columns of D5 to D8 are equal to each other, and the + My row The absolute values of ε described in each column of D1 to D4 are equal to each other, and the absolute values of ε described in each column of D5 to D8 are equal to each other.

  FIG. 26 shows each column indicating the change in capacitance value for the eight main capacitive elements C1 to C8 shown in FIG. 17, and the electrostatic capacitance for the eight sub-capacitance elements D1 to D8 shown in FIG. It is a table | surface which shows the sum with each column which shows the aspect of a capacitance value change. Even if it is assumed that the capacitance values change as shown in the table of FIG. 26 for each of the primary and secondary capacitive element pairs, the six force components are still based on the respective arithmetic expressions shown in FIG. Can be detected. This is because the semi-circular electrodes having the same shape and the same size are arranged so as to have symmetry as described above.

  For example, when the force Fx and the force Fy are obtained based on the formula of FIG. 21, the variation “ε” shown in the table of FIG. 26 is not involved at all, so the same value as that obtained when the table of FIG. 20 is assumed is obtained. . Further, since the + Fz row of the table of FIG. 26 and the + Fz row of the table of FIG. 20 are the same, the same result can be obtained for the force Fz. On the other hand, with respect to moments Mx, My, and Mz, “Δ” in the table of FIG. 20 is replaced with “Δ + ε” in the table of FIG. There is no difference in the substantial detection principle. As a result, even in a modification example in which the electrode arrangement shown in FIG. 24 is used instead of the electrode arrangement shown in FIG. 18, six force components can be detected based on the respective arithmetic expressions shown in FIG.

  FIG. 27 is an enlarged plan view showing a second modification of the 16 electrodes shown in FIG. 18 (the shape and arrangement of the eight electrodes F1 to F8 constituting the sub-capacitance element are different). is there. In this modification, the two electrodes on the support substrate side constituting the sixth and eighth sub-capacitance elements pass through the center point of the disk arranged around the central axis of the first columnar body T1. The two electrodes on the support substrate side, which are constituted by two semicircular electrodes F6 and F8 obtained by cutting along a reference axis parallel to the Y axis, constitute the fifth and seventh sub-capacitance elements. The semicircular electrodes F5 and F7 obtained by cutting the disk arranged around the central axis of the second columnar body T2 along the reference axis passing through the central point and parallel to the Y axis. A disk in which two electrodes on the side of the supporting substrate constituting the second and fourth sub-capacitance elements are arranged around the center axis of the third columnar body T3 passes through the center point and passes through the center axis. Is formed by two semicircular electrodes F2 and F4 obtained by cutting along a reference axis parallel to A disk in which the two electrodes on the support substrate side constituting the first and third sub-capacitance elements are arranged around the central axis of the fourth columnar body T4 passes through the center point and is parallel to the X axis. It is constituted by two semicircular electrodes F1 and F3 obtained by cutting along a reference axis.

  The second modification shown in FIG. 27 corresponds to what is obtained by rotating the semicircular sub fixed electrodes F1 to F8 by 90 ° in the first modification shown in FIG. In the sub-capacitance elements D1 to D8 constituted by the sub-fixed electrodes F1 to F8 having the shape and arrangement as shown in FIG. 27, the capacitance value changes as shown in the table of FIG. When the table of FIG. 28 is compared with the table of FIG. 19, there are still fluctuations ± ε in many columns. This is because also in the second modified example shown in FIG. 27, the variation ± ε for detecting the inclination of the columnar body occurs in the sub-capacitance elements D1 to D8.

  FIG. 29 shows each column indicating the change in capacitance value for the eight main capacitance elements C1 to C8 shown in FIG. 17, and the electrostatic capacitance for the eight sub capacitance elements D1 to D8 shown in FIG. It is a table | surface which shows the sum with each column which shows the aspect of a capacitance value change. Even if it is assumed that the capacitance value changes as shown in the table of FIG. 29 for each of the primary and secondary capacitive element pairs, the six force components are still based on the respective arithmetic expressions shown in FIG. Can be detected. This is because, as the sub-fixed electrodes F1 to F8, semicircular electrodes having the same shape and size are arranged so as to have symmetry.

  For example, when the force Fx and the force Fy are obtained based on the equation of FIG. 21, “Δ” in the table of FIG. 20 is replaced with “Δ + ε” or “Δ−ε” in the table of FIG. The same result of “4Δ” is obtained. Further, since each row of + Fz, + Mx, + My, + Mz in the table of FIG. 29 and each corresponding row of the table of FIG. 20 are the same, the same result is obtained for the force Fz and the moments Mx, My, Mz. Eventually, even in a modified example in which the electrode arrangement shown in FIG. 27 is used instead of the electrode arrangement shown in FIG. 18, six force components can be detected based on the respective arithmetic expressions shown in FIG.

<9-4: Subcapacitance element shape and arrangement conditions>
As described above, two variations have been described as variations in the shape and arrangement of the sub-capacitance elements. However, in implementing the present invention, there are various other variations in the shape and arrangement of the sub-capacitance elements. Can be adopted.

  Here, let us consider the shape and arrangement conditions of the sub-capacitance element. The role of the sub-capacitance element in the present invention is to generate a variation ε for canceling the other-axis interference component δ generated in the main capacitance element when the moment Mx or My acts. Therefore, in the plan view shown in FIG. 30, the arrangement of the electrode F1 constituting the sub-capacitance element D1 is considered with respect to the electrode E1 constituting the main capacitance element C1. FIG. 30 is a plan view of the support substrate 300, and G31 to G34 indicate grooves formed below the lower end side thin portions 215, 225, 235, and 245, and sensors S1 to S4 are formed, respectively. Corresponds to the region.

  As shown in the figure, it is assumed that the main fixed electrode E1 is disposed in the groove G31, and when the moment Mx is applied, the other-axis interference component δ generated in the main capacitive element C1 constituted by the main fixed electrode E1. Consider the arrangement of the sub-capacitance element D1 that generates the variation ε for canceling out. Considering canceling by connecting the main and sub-capacitance elements in parallel, it is necessary that the sign of ε is opposite to the sign of δ when the moment Mx is applied. Then, the arrangement candidate of the sub-fixed electrode F1 constituting the sub-capacitance element D1 is any one of the areas A1, A2, and A4 indicated by hatching in the drawing. However, when the detection sensitivity is taken into consideration, it can be understood that the region A4 is optimal as the arrangement candidate of the auxiliary fixed electrode F1. The change in the distance between the electrodes when the moment Mx is applied is most remarkable in the region A4.

  Similarly, when considering the arrangement of the sub-fixed electrodes F1 to F8 in consideration of cancellation of other-axis interference components when the moment My acts, the electrodes F6 and F8 are arranged in the groove G31 (sensor S1), and the electrodes F5 and F7 are preferably disposed in the groove G32 (sensor S2), electrodes F2 and F4 are preferably disposed in the groove G33 (sensor S3), and electrodes F1 and F3 are preferably disposed in the groove G34 (sensor S4). I understand. In the basic embodiment and the modification examples described so far, the sub-fixed electrodes F1 to F8 are arranged based on such a concept.

  Next, consider the shapes of the sub-fixed electrodes F1 to F8. FIG. 31 is a plan view for explaining an example of the arrangement of the electrodes E1, E2 constituting the main capacitive elements C1, C2 and the electrodes F1, F4 constituting the sub capacitive elements D1, D4. The main fixed electrodes E1 and E2 are electrodes obtained by cutting an annular band disposed around the central axis Q1 of the first columnar body T1 along the X axis. On the other hand, the sub fixed electrode F1 corresponding to the main fixed electrode E1 is a circular electrode disposed around the central axis Q4 of the fourth columnar body T4, and the sub fixed electrode corresponding to the main fixed electrode E4. F4 is an annular electrode disposed around the central axis Q3 of the third columnar body T3.

  An embodiment in which such a shape is adopted for the main fixed electrode and the sub fixed electrode is a basic embodiment shown in FIG. An advantage of adopting such a shape is that a pair of sub-fixed electrodes can be arranged in an inner region of an annular band made up of a pair of main fixed electrodes. In the case of the example shown in FIG. 31, an annular sub-fixed electrode F6 is actually arranged in the inner region of the annular band made up of the main fixed electrodes E1 and E2, and a circular sub-fixed is further formed in the inner region. The electrode F8 is disposed. Considering the arrangement of two main fixed electrodes and two sub fixed electrodes in one sensor region, each electrode shape shown in FIG. 31 is very efficient.

  Further, as shown in FIG. 31, the sub-fixed electrode is a circular electrode (F1) or an annular electrode (F4), so that the inclination of the columnar body is not detected as a capacitance value. There are also benefits. Therefore, as shown in the table of FIG. 19, the occurrence of unnecessary variation ε is suppressed only to the + Fz row. For example, the sub-capacitance element D1 constituted by the circular sub-fixed electrode F1 shown in FIG. 31 is related to both the YZ plane and the reference plane X4 including the central axis Q4 of the fourth columnar body and parallel to the XZ plane. The shape is symmetrical. Similarly, the sub-capacitance element D4 configured by the annular sub-fixed electrode F4 has a surface with respect to both the YZ plane and the reference plane X3 including the central axis Q3 of the third columnar body and parallel to the XZ plane. It has a symmetrical shape. For this reason, the capacitance value does not change in the sub-capacitance element based on the inclination of the columnar body.

  Eventually, in order to prevent the inclination of the columnar body from being detected as the capacitance value, the two electrodes F6 and F8 on the support substrate side constituting the sixth and eighth sub-capacitance elements are both the first The reference surface including the central axis of the columnar body T1 and parallel to the YZ plane has a shape that is plane-symmetric with respect to both the XZ plane and 2 on the support substrate side that constitutes the fifth and seventh sub-capacitance elements. Each of the electrodes F5 and F7 has a symmetrical shape with respect to both the reference plane including the central axis of the second columnar body T2 and parallel to the YZ plane, and the XZ plane. Both of the two electrodes F2 and F4 on the support substrate side constituting the sub-capacitance element 4 include both the reference plane including the central axis of the third columnar body T3 and parallel to the XZ plane, and the YZ plane. , Having a symmetrical shape and supporting the first and third sub-capacitance elements. The two electrodes F1 and F3 on the substrate side both have a shape that is plane-symmetric with respect to both the reference plane that includes the central axis of the fourth columnar body T4 and is parallel to the XZ plane, and the YZ plane. You can do it.

  On the other hand, FIG. 32 is a plan view showing another arrangement form of the sub fixed electrodes F1, F2 with respect to the main fixed electrodes E1, E2, and corresponds to the above-described first modification (example shown in FIG. 24). is there. Although the pair of sub-fixed electrodes can be arranged in the inner region of the annular band composed of the pair of main fixed electrodes, the shape of the sub-fixed electrodes is different from the above example. FIG. 24 shows an example in which a semicircular sub-fixed electrode is used, but FIG. 32 shows an example in which rectangular sub-fixed electrodes F1 and F2 are arranged for general explanation. Here, the sub-capacitance element D1 configured by the sub-fixed electrode F1 does not have symmetry with respect to the YZ plane, but includes a plane with respect to the reference plane X4 including the central axis Q4 of the fourth columnar body and parallel to the XZ plane. It has a symmetrical shape. Similarly, the sub-capacitance element D2 constituted by the sub-fixed electrode F2 has no symmetry with respect to the YZ plane, but includes a plane with respect to the reference plane X3 including the central axis Q3 of the third columnar body and parallel to the XZ plane. It has a symmetrical shape.

  When the electrode arrangement shown in FIG. 24 is adopted, the capacitance values shown in the table of FIG. 26 change, and even when it is assumed that such a capacitance value change occurs, FIG. As described above, it is possible to detect six force components based on the above equation. Here, in order to cause the change in the capacitance value shown in the table of FIG. 26, the two electrodes F6 and F8 on the support substrate side constituting the sixth and eighth sub-capacitance elements are eventually Also, the two electrodes on the side of the supporting substrate constituting the fifth and seventh sub-capacitance elements have a shape that is symmetrical with respect to a reference plane that includes the central axis of the first columnar body T1 and is parallel to the YZ plane. Each of F5 and F7 has a shape that is symmetrical with respect to a reference plane that includes the central axis of the second columnar body T2 and is parallel to the YZ plane, and forms the second and fourth sub-capacitance elements. The two electrodes F2 and F4 are both symmetrical with respect to the reference plane including the central axis of the third columnar body T3 and parallel to the XZ plane, and the first and third sub-capacitance elements are Both of the two electrodes F1 and F3 on the support substrate side constituting the fourth columnar body With respect to a reference plane parallel to the XZ plane including the center axis of 4, it is sufficient to form a shape which is plane-symmetrical.

  On the other hand, FIG. 33 is a plan view showing still another arrangement of the sub-fixed electrodes F1, F2 with respect to the main fixed electrodes E1, E2, and corresponds to the above-described second modification (example shown in FIG. 27). It is. Although the pair of sub-fixed electrodes can be arranged in the inner region of the annular band composed of the pair of main fixed electrodes, the shape of the sub-fixed electrodes is different from the above example. FIG. 27 shows an example in which a semicircular sub-fixed electrode is used, but FIG. 32 shows an example in which elliptical sub-fixed electrodes F1 and F2 are arranged for general explanation. Here, the sub-capacitance element D1 constituted by the sub-fixed electrode F1 has symmetry with respect to the YZ plane, but is symmetric with respect to the reference plane X4 including the central axis Q4 of the fourth columnar body and parallel to the XZ plane. Does not have sex. Similarly, the sub-capacitance element D2 configured by the sub-fixed electrode F2 has symmetry with respect to the YZ plane, but includes symmetry with respect to the reference plane X3 including the central axis Q3 of the third columnar body and parallel to the XZ plane. Does not have sex.

  When the electrode arrangement shown in FIG. 27 is adopted, a change in the capacitance value shown in the table of FIG. 29 occurs. Even when it is assumed that such a change in the capacitance value occurs, FIG. As described above, it is possible to detect six force components based on the above equation. However, the present inventor practically uses the electrode arrangement pattern shown in FIG. 18 shown in the basic embodiment and the first modification rather than adopting the electrode arrangement pattern shown in FIG. 27 shown as the second modification. It is considered more preferable to adopt the electrode arrangement pattern shown in FIG. This is because the electrode arrangement pattern shown in FIG. 27 has a factor that causes a decrease in detection sensitivity. That is, the term “Δ−ε” is included in the + Fx and + Fy rows in FIG. 29, and the detection value obtained by the sub-capacitance element with respect to the detection value “Δ” obtained by the main capacitance element. Since the operation of reducing the value “ε” is performed, the operation of decreasing the detection sensitivity is intentionally performed. Therefore, the inventor of the present application considers that it is optimal to adopt the electrode arrangement of FIG. 18 or the electrode arrangement of FIG. 24 in practicing the present invention.

<9-5: Setting Method for Other-axis Interference Component δ = Fluctuation ε>
In the force detection device according to the present invention, when the moment Mx around the X-axis acts on the force receiving member, the change in capacitance value ± δ generated in the i-th (i = 1 to 4) main capacitance element Is set to be equal to the absolute value of the change in capacitance value ± ε generated in the i-th sub-capacitance element, and the moment My around the Y-axis acts on the force receiving member. In this case, the absolute value of the variation ± δ of the capacitance value occurring in the jth (j = 5 to 8) main capacitance element and the variation of the capacitance value occurring in the jth subcapacitance device Setting is made so that the absolute value of ± ε is equal.

  As a typical method for performing such setting, the ratio of the area of the electrode constituting the main capacitive element and the area of the electrode constituting the sub-capacitance element corresponding thereto corresponds to the moment around the X axis in the force receiving body. When the moment My around the Mx or Y axis acts, the absolute value of the change in capacitance value ± δ generated in the main capacitance element and the absolute value of the change in capacitance value ± ε generated in the sub capacitance element The method of making the area ratio so that is equal is described in §7.

  However, the method of adjusting the capacitance value generated in each capacitive element is not limited to the method of adjusting the electrode area. For example, a method of adjusting the distance between the electrodes can be employed, or a method of filling a fluid medium between the electrodes and adjusting the dielectric constant of the medium can be employed. However, when used as a mass-produced commercial product, as described above, it is most efficient to adopt a method of adjusting the electrode area.

10: Power receiving body 11: First columnar body 12: Second columnar body 13: Third columnar body 14: Fourth columnar body 20: Support substrate 21: First sensor 22: Second sensor 23 : Third sensor 24: Fourth sensor 30: Detection circuit 100: Power receiving body 110: Columnar projection 115: Upper end thin portion 120: Columnar projection 125: Upper end thin portion 130: Columnar projection 135: Upper end Side thin portion 140: cylindrical protrusion 145: upper end thin portion 200: intermediate 210: cylindrical protrusion 215: lower end thin portion 220: cylindrical protrusion 225: lower end thin portion 230: cylindrical protrusion 235: lower end thin Portion 240: Cylindrical protrusion 245: Lower end thin portion 250: Control wall 260: Control wall 300: Support substrate 400: Measuring jig 410: Connection portion 420: Upper lid portion 430: Side wall portion 440: Flange portions A1 to A4: Electrode placement region B1 B8: Bonding pads C1 to C8: Capacitance values D1 to D8 of the main capacitance element / main capacitance element: Capacitance values d1 to d3 of the subcapacitance element / subcapacitance element: Gaps dimensions E1 to E8: Main capacitance element Constructing electrodes F1 to F8: Electrodes Fx composing sub-capacitance elements: X-axis direction force Fy: Y-axis direction force Fz: Z-axis direction force fz: Tensile force / pressing force G11 acting on the support substrate G34: Groove Mx: X-axis moment My: Y-axis moment Mz: Z-axis moment O: Coordinate system origin O ': Auxiliary coordinate system origin P1-P3: Action points Q1-Q4: Center Axis r1, r2: Length from origin to action point S1 to S4: Force sensors T1 to T4: Columnar body V (Mx): Moment Mx detection value V (Fy): Force Fy detection value XYZ: Detection target Three to define the force Original coordinate system X′Y′Z ′: Auxiliary coordinate system X2 and X4 having an origin at the center position of the force receiving body X: Reference axis parallel to the X axis Δ: Change in capacitance value of main capacitive element δ: Main Change in capacitance value of capacitive element (interaxial interference component)
ε: change in capacitance value of sub-capacitance element θ1, θ2: inclination angle of columnar bodies 11, 12

Claims (23)

A support substrate, a force receiving body disposed above the support substrate, and four columnar bodies for connecting the support substrate and the force receiving body, in a state where the support substrate is fixed A force detection device for detecting a force acting on the force receiving body,
Each upper end of the four columnar bodies is connected to the power receiving body via a flexible member, and each lower end of the four columnar bodies has flexibility. The lower end side thin part is connected,
The lower end side thin portion is connected to the support substrate via a pedestal so that the lower end side thin portion is disposed parallel to the upper surface of the support substrate at an upper position with a predetermined distance from the upper surface of the support substrate. , The center of the upper surface is connected to the lower end of the columnar body,
An XY plane is positioned so as to be parallel to the upper surface of the support substrate at or above the upper surface of the support substrate, and the Z axis with the upper side being positive and the lower side being negative is substantially the center of the upper surface of the support substrate When defining the XYZ three-dimensional coordinate system to pass through the position,
The four columnar bodies are arranged so that their central axes are parallel to the Z axis, and the first columnar body is arranged at a position where the central axis intersects the positive part of the X axis. The second columnar body is disposed at a position where the central axis intersects the negative portion of the X axis, and the third columnar body is disposed at a position where the central axis intersects the positive portion of the Y axis. And the fourth columnar body is arranged at a position where the central axis intersects the negative part of the Y-axis,
One electrode is formed on the lower surface of the lower end side thin portion in a space sandwiched between the lower end side thin portion of the first columnar body and the upper surface of the support substrate facing the first columnar body, and the other electrode is the support A first sensor comprising a plurality of capacitive elements formed on the upper surface of the substrate is disposed;
One electrode is formed on the lower surface of the lower end thin portion in a space sandwiched between the lower end thin portion of the second columnar body and the upper surface of the support substrate opposed thereto, and the other electrode is the support A second sensor comprising a plurality of capacitive elements formed on the upper surface of the substrate is disposed;
One electrode is formed on the lower surface of the lower-side thin portion in a space sandwiched between the lower-side thin portion of the third columnar body and the upper surface of the support substrate facing the third columnar body, and the other electrode is the support A third sensor comprising a plurality of capacitive elements formed on the upper surface of the substrate is disposed;
One electrode is formed on the lower surface of the lower-side thin portion in a space sandwiched between the lower-side thin portion of the fourth columnar body and the upper surface of the support substrate facing the fourth columnar body, and the other electrode is the support A fourth sensor comprising a plurality of capacitive elements formed on the upper surface of the substrate is disposed;
The first sensor has a first main capacitive element located in the first quadrant of the XY coordinate system, and a second main capacitive element located in the fourth quadrant of the XY coordinate system,
The second sensor has a third main capacitive element located in the second quadrant of the XY coordinate system, and a fourth main capacitive element located in the third quadrant of the XY coordinate system,
The third sensor has a second sub-capacitance element and a fourth sub-capacitance element,
The fourth sensor has a first sub-capacitance element and a third sub-capacitance element,
Further comprising a detection circuit for detecting a predetermined direction component of the force acting on the force receiving body based on a capacitance value of each capacitive element;
When a moment Mx around the X-axis acts on the force receiving body, the absolute value of the change in the capacitance value generated in the first main capacitive element and the capacitance generated in the first sub-capacitance element The absolute value of the change in value becomes equal, and the absolute value of the change in capacitance value generated in the second main capacitive element and the change in the capacitance value generated in the second sub-capacitance element. The absolute value is equal, and the absolute value of the change in capacitance value generated in the third main capacitive element is equal to the absolute value of the change in capacitance value generated in the third sub-capacitance element. The absolute value of the change in the capacitance value generated in the fourth main capacitive element is equal to the absolute value of the change in the capacitance value generated in the fourth sub-capacitance element. A capacitive element is constructed,
The detection circuit has a capacitance value of the first main capacitance element as C1, a capacitance value of the first sub capacitance element as D1, a capacitance value of the second main capacitance element as C2, The capacitance value of the second sub-capacitance element is D2, the capacitance value of the third main capacitance element is C3, the capacitance value of the third sub-capacitance element is D3, and the fourth main capacitance element is D4. When the capacitance value of the capacitive element is C4 and the capacitance value of the fourth sub-capacitance element is D4, the Y-axis direction component Fy of the force acting on the force receiving member is
Fy = (C1 + D1) − (C2 + D2) + (C3 + D3) − (C4 + D4)
A force detection device characterized in that the force detection device is obtained using an arithmetic expression. The force detection device according to claim 1,
The detection circuit further detects a moment component My around the Y axis of the force acting on the power receiving body.
My = (C1 + D1) + (C2 + D2)-(C3 + D3)-(C4 + D4)
A force detection device characterized in that the force detection device is obtained using an arithmetic expression. The force detection device according to claim 1 or 2,
The detection circuit further includes a Z-axis direction component Fz of the force acting on the power receiving body,
Fz = − ((C1 + D1) + (C2 + D2) + (C3 + D3) + (C4 + D4))
A force detection device characterized in that the force detection device is obtained using an arithmetic expression. In the force detection apparatus in any one of Claims 1-3,
Wiring for connecting the first main capacitive element and the first sub-capacitor in parallel with each other; wiring for connecting the second main capacitive element and the second sub-capacitor in parallel with each other; Wiring for connecting the third main capacitive element and the third sub-capacitor in parallel with each other; wiring for connecting the fourth main capacitive element and the fourth sub-capacitor in parallel with each other; Further comprising
The detection circuit uses, as the value of “C1 + D1”, a capacitance value of a combined capacitive element configured by parallel connection of the first main capacitive element and the first subcapacitor element, and the second main capacitance A capacitance value of a composite capacitive element configured by parallel connection of an element and the second sub-capacitance element is used as a value of “C2 + D2”, and the third main capacitive element, the third sub-capacitance element, The combined capacitance element configured by parallel connection of the fourth main capacitance element and the fourth subcapacitance element, using the capacitance value of the combined capacitance element configured by the parallel connection of “C3 + D3” as the value The force detection device using the capacitance value of “C4 + D4”. In the force detection device according to any one of claims 1 to 4,
Each of the lower end thin portions is made of a conductive material, and the lower end thin portions themselves function as a common electrode for a plurality of capacitive elements constituting the same sensor. The force detection device according to claim 5,
The four electrodes on the support substrate side constituting the first to fourth main capacitive elements are constituted by electrodes having the same shape and the same size, and these four electrode arrangement patterns are represented by an XZ plane and a YZ. A force detection device characterized by being symmetrical with respect to both planes. A support substrate, a force receiving body disposed above the support substrate, and four columnar bodies for connecting the support substrate and the force receiving body, in a state where the support substrate is fixed A force detection device for detecting a force acting on the force receiving body,
Each upper end of the four columnar bodies is connected to the power receiving body via a flexible member, and each lower end of the four columnar bodies has flexibility. The lower end side thin part is connected,
The lower end side thin portion is connected to the support substrate via a pedestal so that the lower end side thin portion is disposed parallel to the upper surface of the support substrate at an upper position with a predetermined distance from the upper surface of the support substrate. , The center of the upper surface is connected to the lower end of the columnar body,
An XY plane is positioned so as to be parallel to the upper surface of the support substrate at or above the upper surface of the support substrate, and the Z axis with the upper side being positive and the lower side being negative is substantially the center of the upper surface of the support substrate When defining the XYZ three-dimensional coordinate system to pass through the position,
The four columnar bodies are arranged so that their central axes are parallel to the Z axis, and the first columnar body is arranged at a position where the central axis intersects the positive part of the X axis. The second columnar body is disposed at a position where the central axis intersects the negative portion of the X axis, and the third columnar body is disposed at a position where the central axis intersects the positive portion of the Y axis. And the fourth columnar body is arranged at a position where the central axis intersects the negative part of the Y-axis,
One electrode is formed on the lower surface of the lower end side thin portion in a space sandwiched between the lower end side thin portion of the first columnar body and the upper surface of the support substrate facing the first columnar body, and the other electrode is the support A first sensor comprising a plurality of capacitive elements formed on the upper surface of the substrate is disposed;
One electrode is formed on the lower surface of the lower end thin portion in a space sandwiched between the lower end thin portion of the second columnar body and the upper surface of the support substrate opposed thereto, and the other electrode is the support A second sensor comprising a plurality of capacitive elements formed on the upper surface of the substrate is disposed;
One electrode is formed on the lower surface of the lower-side thin portion in a space sandwiched between the lower-side thin portion of the third columnar body and the upper surface of the support substrate facing the third columnar body, and the other electrode is the support A third sensor comprising a plurality of capacitive elements formed on the upper surface of the substrate is disposed;
One electrode is formed on the lower surface of the lower-side thin portion in a space sandwiched between the lower-side thin portion of the fourth columnar body and the upper surface of the support substrate facing the fourth columnar body, and the other electrode is the support A fourth sensor comprising a plurality of capacitive elements formed on the upper surface of the substrate is disposed;
The first sensor includes a first main capacitive element located in the first quadrant of the XY coordinate system, a second main capacitive element located in the fourth quadrant of the XY coordinate system, and a sixth sub-capacitive element. And an eighth sub-capacitance element,
The second sensor includes a third main capacitive element located in the second quadrant of the XY coordinate system, a fourth main capacitive element located in the third quadrant of the XY coordinate system, and a fifth sub-capacitive element. And a seventh sub-capacitor element,
The third sensor includes a fifth main capacitive element located in the first quadrant of the XY coordinate system, a sixth main capacitive element located in the second quadrant of the XY coordinate system, and a second subcapacitor element. And a fourth sub-capacitor element,
The fourth sensor includes a seventh main capacitive element located in the fourth quadrant of the XY coordinate system, an eighth main capacitive element located in the third quadrant of the XY coordinate system, and a first sub-capacitive element. A third sub-capacitor element,
Further comprising a detection circuit for detecting a predetermined direction component of the force acting on the force receiving body based on a capacitance value of each capacitive element;
When a moment Mx around the X-axis acts on the force receiving body, the absolute value of the change in the capacitance value generated in the first main capacitive element and the capacitance generated in the first sub-capacitance element The absolute value of the change in value becomes equal, and the absolute value of the change in capacitance value generated in the second main capacitive element and the change in the capacitance value generated in the second sub-capacitance element. The absolute value is equal, and the absolute value of the change in capacitance value generated in the third main capacitive element is equal to the absolute value of the change in capacitance value generated in the third sub-capacitance element. The absolute value of the change in the capacitance value generated in the fourth main capacitive element is equal to the absolute value of the change in the capacitance value generated in the fourth sub-capacitance element,
When a moment My around the Y-axis acts on the force receiving body, the absolute value of the change in the capacitance value generated in the fifth main capacitive element and the capacitance generated in the fifth sub-capacitance element The absolute value of the change in the value becomes equal, and the absolute value of the change in the capacitance value generated in the sixth main capacitive element and the change in the capacitance value generated in the sixth sub-capacitance element. The absolute value is equal, and the absolute value of the change in capacitance value that occurs in the seventh main capacitance element is equal to the absolute value of the change in capacitance value that occurs in the seventh subcapacitance element. And the absolute value of the change in capacitance value generated in the eighth main capacitive element is equal to the absolute value of the change in capacitance value generated in the eighth sub-capacitance element. A capacitive element is constructed,
The detection circuit has a capacitance value of the first main capacitance element as C1, a capacitance value of the first sub capacitance element as D1, a capacitance value of the second main capacitance element as C2, The capacitance value of the second sub-capacitance element is D2, the capacitance value of the third main capacitance element is C3, the capacitance value of the third sub-capacitance element is D3, and the fourth main capacitance element is D4. The capacitance value of the capacitive element is C4, the capacitance value of the fourth sub-capacitance element is D4, the capacitance value of the fifth main capacitance element is C5, and the capacitance of the fifth sub-capacitance element. The capacitance value is D5, the capacitance value of the sixth main capacitance element is C6, the capacitance value of the sixth sub capacitance element is D6, and the capacitance value of the seventh main capacitance element is C7, When the capacitance value of the seventh sub-capacitance element is D7, the capacitance value of the eighth main capacitance element is C8, and the capacitance value of the eighth sub-capacitance element is D8. ,
Y-axis direction component Fy of the force acting on the force receiving member is
Fy = (C1 + D1) − (C2 + D2) + (C3 + D3) − (C4 + D4)
Using an arithmetic expression
X-axis direction component Fx of the force acting on the force receiving body,
Fx = (C5 + D5)-(C6 + D6) + (C7 + D7)-(C8 + D8)
A force detection device characterized in that the force detection device is obtained using an arithmetic expression. The force detection device according to claim 7,
The detection circuit further detects a moment component My around the Y axis of the force acting on the power receiving body.
My = (C1 + D1) + (C2 + D2)-(C3 + D3)-(C4 + D4)
The moment component Mx around the X axis of the force acting on the force receiving body is calculated using the following equation:
Mx = − (C5 + D5) − (C6 + D6) + (C7 + D7) + (C8 + D8)
A force detection device characterized in that the force detection device is obtained using an arithmetic expression. The force detection device according to claim 7 or 8,
The detection circuit further includes a Z-axis direction component Fz of the force acting on the power receiving body,
Fz = − ((C1 + D1) + (C2 + D2) + (C3 + D3) + (C4 + D4) + (C5 + D5) + (C6 + D6) + (C7 + D7) + (C8 + D8))
A force detection device characterized in that the force detection device is obtained using an arithmetic expression. In the force detection device according to any one of claims 7 to 9,
The detection circuit further detects a moment component Mz around the Z-axis of the force acting on the power receiving body.
Mz = (C1 + D1)-(C2 + D2)-(C3 + D3) + (C4 + D4)-(C5 + D5) + (C6 + D6) + (C7 + D7)-(C8 + D8)
A force detection device characterized in that the force detection device is obtained using an arithmetic expression. In the force detection apparatus in any one of Claims 7-10,
Wiring for connecting the first main capacitive element and the first sub-capacitor in parallel with each other; wiring for connecting the second main capacitive element and the second sub-capacitor in parallel with each other; Wiring for connecting the third main capacitive element and the third sub-capacitor in parallel with each other; wiring for connecting the fourth main capacitive element and the fourth sub-capacitor in parallel with each other; Wiring for connecting the fifth main capacitive element and the fifth sub-capacitor in parallel with each other; wiring for connecting the sixth main capacitive element and the sixth sub-capacitor in parallel with each other; Wiring for connecting the seventh main capacitance element and the seventh subcapacitance element in parallel with each other; wiring for connecting the eighth main capacitance element and the eighth subcapacitance element in parallel with each other; Further comprising
The detection circuit uses, as the value of “C1 + D1”, a capacitance value of a combined capacitive element configured by parallel connection of the first main capacitive element and the first subcapacitor element, and the second main capacitance A capacitance value of a composite capacitive element configured by parallel connection of an element and the second sub-capacitance element is used as a value of “C2 + D2”, and the third main capacitive element, the third sub-capacitance element, The combined capacitance element configured by parallel connection of the fourth main capacitance element and the fourth subcapacitance element, using the capacitance value of the combined capacitance element configured by the parallel connection of “C3 + D3” as the value Is used as the value of “C4 + D4”, and the capacitance value of the combined capacitive element formed by parallel connection of the fifth main capacitive element and the fifth sub-capacitance element is “C5 + D5”. The sixth main content used as a value A capacitance value of a composite capacitive element configured by parallel connection of an element and the sixth sub-capacitance element is used as a value of “C6 + D6”, and the seventh main capacitive element, the seventh sub-capacitance element, The combined capacitance element configured by parallel connection of the eighth main capacitance element and the eighth subcapacitance element, using the capacitance value of the combined capacitance element configured by the parallel connection of “8” as the value of “C7 + D7” The force detection device using the capacitance value of “C8 + D8”. The force detection device according to any one of claims 7 to 11,
The four columnar bodies are composed of structures of the same shape and the same size, and the arrangement pattern of these four columnar bodies is plane-symmetric with respect to both the XZ plane and the YZ plane. A force detection device characterized by. The force detection device according to claim 12,
Each of the lower end thin portions is made of a conductive material, and the lower end thin portions themselves function as a common electrode for a plurality of capacitive elements constituting the same sensor. The force detection device according to claim 13,
The eight electrodes on the support substrate side constituting the first to eighth main capacitive elements are constituted by electrodes of the same shape and the same size, and the arrangement pattern of these eight electrodes is an XZ plane and A force detection device characterized by being symmetrical with respect to both YZ planes. The force detection device according to claim 14, wherein
The two electrodes on the support substrate side constituting the first and second main capacitive elements cut the first annular band disposed around the central axis of the first columnar body along the X axis. Composed of two electrodes obtained by
The two electrodes on the support substrate side constituting the third and fourth main capacitive elements cut the second annular band disposed around the central axis of the second columnar body along the X axis. Composed of two electrodes obtained by
Two electrodes on the support substrate side constituting the fifth and sixth main capacitive elements cut the third annular band arranged around the central axis of the third columnar body along the Y axis. Composed of two electrodes obtained by
The four electrodes on the support substrate side constituting the seventh and eighth main capacitive elements cut the fourth annular band arranged around the central axis of the fourth columnar body along the Y axis. Composed of two electrodes obtained by
Two electrodes on the support substrate side constituting the sixth and eighth sub-capacitance elements are arranged in an inner region surrounded by the first annular band,
Two electrodes on the support substrate side constituting the fifth and seventh sub-capacitance elements are arranged in an inner region surrounded by the second annular band,
Two electrodes on the support substrate side constituting the second and fourth sub-capacitance elements are arranged in an inner region surrounded by the third annular band,
A force detection device, wherein two electrodes on the support substrate side constituting the first and third sub-capacitance elements are arranged in an inner region surrounded by the fourth annular band. The force detection device according to claim 15,
A force detection device characterized in that each columnar body is formed of a cylindrical structure, each lower end thin portion is formed of a disk-shaped structure, and each annular band is formed of an annular structure. The force detection device according to claim 16, wherein
Of the two electrodes on the support substrate side constituting the sixth and eighth sub-capacitance elements, one is constituted by an electrode having an annular shape, and the other is constituted by an electrode disposed in the inner region thereof,
Of the two electrodes on the support substrate side constituting the fifth and seventh sub-capacitance elements, one is constituted by an electrode having an annular shape, and the other is constituted by an electrode arranged in the inner region thereof,
Of the two electrodes on the support substrate side constituting the second and fourth sub-capacitance elements, one is constituted by an electrode having an annular shape, and the other is constituted by an electrode arranged in the inner region thereof,
Of the two electrodes on the support substrate side constituting the first and third sub-capacitance elements, one is constituted by an electrode having an annular shape, and the other is constituted by an electrode disposed in the inner region. A force detection device characterized by that. The force detection device according to claim 16, wherein
2 obtained by cutting, along the X-axis, a disk in which two electrodes on the support substrate side constituting the sixth and eighth sub-capacitance elements are arranged around the central axis of the first columnar body. Composed of a semicircular electrode,
2 obtained by cutting, along the X-axis, a disk in which two electrodes on the support substrate side constituting the fifth and seventh sub-capacitance elements are arranged around the central axis of the second columnar body. Composed of a semicircular electrode,
2 obtained by cutting, along the Y-axis, a disk in which two electrodes on the support substrate side constituting the second and fourth sub-capacitance elements are arranged around the central axis of the third columnar body. Composed of a semicircular electrode,
2 obtained by cutting, along the Y-axis, a disk in which two electrodes on the support substrate side constituting the first and third sub-capacitance elements are arranged around the central axis of the fourth columnar body. A force detection device comprising a plurality of semicircular electrodes. The force detection device according to claim 16, wherein
Reference is made to a disk in which the two electrodes on the supporting substrate side constituting the sixth and eighth sub-capacitance elements are arranged around the central axis of the first columnar body, passing through the central point and parallel to the Y axis It is composed of two semicircular electrodes obtained by cutting along the axis,
Reference is made to a disk in which the two electrodes on the support substrate side constituting the fifth and seventh sub-capacitance elements are arranged around the central axis of the second columnar body, passing through the central point and parallel to the Y axis It is composed of two semicircular electrodes obtained by cutting along the axis,
Reference is made to a disk in which the two electrodes on the support substrate side constituting the second and fourth sub-capacitance elements are arranged around the central axis of the third columnar body, passing through the central point and parallel to the X axis It is composed of two semicircular electrodes obtained by cutting along the axis,
Reference is made to a disk in which the two electrodes on the support substrate side constituting the first and third sub-capacitance elements are arranged around the central axis of the fourth columnar body, passing through the central point and parallel to the X axis A force detection device comprising two semicircular electrodes obtained by cutting along an axis. The force detection device according to any one of claims 14 to 16,
Both the two electrodes on the support substrate side constituting the sixth and eighth sub-capacitance elements are both related to the reference plane including the central axis of the first columnar body and parallel to the YZ plane, and the XZ plane. A shape that is plane symmetric,
Both the two electrodes on the support substrate side constituting the fifth and seventh sub-capacitance elements are both related to the reference plane including the central axis of the second columnar body and parallel to the YZ plane, and the XZ plane. A shape that is plane symmetric,
Both the two electrodes on the support substrate side constituting the second and fourth sub-capacitance elements are both related to the reference plane including the central axis of the third columnar body and parallel to the XZ plane, and the YZ plane. A shape that is plane symmetric,
Both the two electrodes on the support substrate side constituting the first and third sub-capacitance elements are both related to the reference plane including the central axis of the fourth columnar body and parallel to the XZ plane, and the YZ plane. A force detection device characterized by having a shape that is plane-symmetric. The force detection device according to any one of claims 14 to 16,
Each of the two electrodes on the support substrate side constituting the sixth and eighth sub-capacitance elements has a shape that is plane-symmetric with respect to a reference plane that includes the central axis of the first columnar body and is parallel to the YZ plane. ,
Each of the two electrodes on the support substrate side constituting the fifth and seventh sub-capacitance elements has a shape that is plane-symmetric with respect to a reference plane that includes the central axis of the second columnar body and is parallel to the YZ plane. ,
Each of the two electrodes on the support substrate side constituting the second and fourth sub-capacitance elements has a shape that is plane-symmetric with respect to a reference plane that includes the central axis of the third columnar body and is parallel to the XZ plane. ,
Both of the two electrodes on the support substrate side constituting the first and third sub-capacitance elements have a shape that is plane-symmetric with respect to a reference plane that includes the central axis of the fourth columnar body and is parallel to the XZ plane. A force detection device characterized by that. The force detection device according to any one of claims 1 to 21,
When the ratio of the area of the electrode constituting the main capacitive element and the area of the electrode constituting the sub-capacitor corresponding thereto is the moment Mx around the X axis or the moment My around the Y axis acting on the force receiving body In addition, the area ratio is set such that the absolute value of the change in capacitance value generated in the main capacitive element is equal to the absolute value of the change in capacitance value generated in the sub-capacitance element. A force detection device characterized by. In the force detection device according to any one of claims 1 to 22,
As a flexible member for connecting each upper end of the four columnar bodies to the power receiving body, the periphery thereof is connected to the power receiving body, and the center portion of the lower surface is connected to the upper end of the columnar body. A force detecting device provided with a thin upper end side thin portion.

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