JP2019066409A - Force detection device - Google Patents

Abstract

To provide a force detection device capable of detecting a position to which force is applied.SOLUTION: A solid body 2A is arranged fixedly. A force receiving body 3A receives force from one direction, which is a detection object. Detection means 5 has a plurality of capacitance elements 5A-5D arrayed in a direction crossing with a direction of force received by the force receiving body 3A, and each having a capacitance fluctuating corresponding to relative displacement between the force receiving body 3A and the solid body 2A, and detects a position where the force receiving body 3A receives force, based on variation difference between each capacitance of the plurality of capacitance elements 5A-5D.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a force detection device.

  Patent Document 1 discloses a force detection device that detects the magnitude of the force based on the capacitance between the electrodes, which changes in the facing area between the electrodes by receiving the force. ing.

JP, 2011-128096, A

  The force detection device disclosed in Patent Document 1 detects forces and moments in a plurality of directions using a plurality of electrodes. However, in this force detection device, it is difficult to detect the position where the force is applied.

  This invention is made in view of the said situation, and it aims at providing the force detection apparatus which can detect the position to which force was applied.

In order to achieve the above object, a force detection device according to the present invention is
A fixed body to be fixedly arranged,
A receiving body that receives a force from one direction to be detected;
It has a plurality of electrostatic capacitance elements which are arranged in a direction intersecting with the direction of the force received by the force receiving body and whose capacitance varies in accordance with the relative displacement between the force receiving body and the fixed body, A detection unit that detects a position at which the force receiving member receives a force based on a difference in change in capacitance of the capacitance element;
Equipped with

In this case, the power receiving body and the fixed body are connected to each other, and the power receiving body includes a deformable body that is deformed according to the force received by the power receiving body.
In the detection means,
One electrode of the capacitive element is provided on the deformable body,
The other electrode of the capacitive element is provided on the force receiving body or the fixed body,
You may do it.

The deformation body is
The distance between the connection point with the force receiving body and the connection point with the fixed body is connected to the force receiving body and the fixed body so as to change according to the force received by the force receiving body.
It is curved so that the position of the one electrode changes in accordance with the change in the distance between the connection points.
You may do it.

One electrode of the capacitive element is provided on the force receiving body,
The other electrode of the capacitive element is provided on the fixed body,
You may do it.

In the detection means,
A plurality of the capacitive elements are arranged along the direction of the force received by the receiving body,
You may do it.

A two-dimensional orthogonal coordinate system is defined in which the center of the force receiving body is the origin, the axis along the direction of the force received by the force receiving body is the ordinate, and the position where the force receiving body receives the force is the abscissa. In case,
The facing relationship between the force receiving body and the fixed body is axisymmetric with respect to the vertical axis and the horizontal axis,
In the detection means,
The plurality of capacitive elements are disposed in each of the first quadrant, the second quadrant, the third quadrant, and the fourth quadrant of the two-dimensional orthogonal coordinate system.
You may do it.

The force receiving body receives a force from the third quadrant to the second quadrant or a force from the fourth quadrant to the first quadrant,
The detection means
The difference in the amount of change in capacitance of the capacitance element in the first quadrant and the second quadrant, and the difference in the amount of change in capacitance in the capacitance element in the third quadrant and the fourth quadrant, And a calculating unit that calculates the position of the force received by the force receiving body based on
You may do it.

The arithmetic unit is
The magnitude of the force is calculated based on the sum of the change amounts of the capacitances of the capacitance elements in the first, second, third and fourth quadrants.
You may do it.

  According to the present invention, it has a plurality of electrostatic capacitance elements arranged in the direction intersecting with the direction of the force received by the force receiving body, and whose capacitance varies in accordance with the relative displacement between the force receiving body and the fixed body. Therefore, the position to which force is applied can be detected based on the difference in the amount of change in capacitance.

FIG. 1A is a top view of a force detection device according to Embodiment 1 of the present invention. FIG. 1 (B) is a bottom view of the force detection device of FIG. 1 (A). FIG. 1C is a cross-sectional view taken along line A-A of FIG. It is a BB sectional view of FIG. 1 (C) when the position where the force receiving body receives the force is X = 0. It is a schematic diagram which shows the mode of a deformation | transformation of a deformation | transformation body when a force receiving body receives force. It is a figure which shows the variation | change_quantity of an electrostatic capacitance in case the position where a receiving body receives force is X = 0. FIG. It is a BB sectional view of FIG. 1 (C) in which the position where the force receiving body receives the force is X = Δx. It is a figure which shows the variation | change_quantity of an electrostatic capacitance in case the position where a receiving body receives force is X = (DELTA) x. It is a schematic diagram which shows the mode of a deformation | transformation of the deformation | transformation body with respect to the torque around an origin. It is a figure which shows the variation | change_quantity of the electrostatic capacitance with respect to the torque around an origin. FIG. 9A is a top view of a force detection device according to a second embodiment of the present invention. FIG. 9 (B) is a bottom view of the force detection device of FIG. 9 (A). FIG.9 (C) is CC sectional drawing of FIG. 9 (A). It is DD sectional drawing of FIG.9 (C). It is a figure which shows the variation | change_quantity of an electrostatic capacitance when the force receiving body receives force when the position where force receiving body receives force is X = 0. FIG. It is a figure which shows the variation | change_quantity of an electrostatic capacitance in case the position where a receiving body receives force is X = (DELTA) x. It is a top view of the force detection apparatus which concerns on Embodiment 3 of this invention. It is a figure which shows the moving direction of a displacement electrode when the force receiving body receives force when the position where force receiving body receives force is X = 0. FIG. It is a figure which shows the moving direction of a displacement electrode when the force receiving body receives force, when the position from which a force receiving body receives force is X = delta x.

Embodiment 1
First, a first embodiment of the present invention will be described in detail with reference to the drawings.

  As shown in FIG. 1 (A), FIG. 1 (B) and FIG. 1 (C), the force detection device 1A according to the present embodiment is entirely in the form of a rectangular flat plate. The force detection device 1A mainly includes the fixed body 2A and the force receiver 3A, and the entire force detection device 1A includes the fixed body 2A, the force receiver 3A, the first cover KA, and the second cover KB. An outer shape is formed.

  As shown in FIG. 1 (A), the first cover KA faces on the + z side, and as shown in FIG. 1 (B), the fixed body 2A and the second cover KB face on the −z side. doing. The fixed body 2A and the force receiving body 3A are disposed in an internal space formed by the first cover KA and the second cover KB. Further, as shown in FIG. 1 (C) showing an AA cross section in FIG. 1 (A), the fixed body 2A and the force receiving body 3A are arranged in the xy plane. Here, the force receiver 3A is fixed to the first cover KA and the second cover KB. On the other hand, the fixed body 2A is not fixed to the first cover KA and the second cover KB. Therefore, by holding the fixed body 2A and the force receiving body 3A on separate external members, the force receiving body 3A can move on the xy plane in a predetermined range with respect to the fixed body 2A. become.

  As shown in FIG. 2 showing a B-B cross section of FIG. 1C, in the present embodiment, an XY two-dimensional orthogonal coordinate system having an origin O at the center position of the force detection device 1A is defined. In FIG. 2, an X axis (right side in the drawing is + X direction) is defined in the left and right direction of the drawing, and a Y axis (upper side in the drawing is + Y direction) is defined in the vertical direction. The x-axis is parallel to the x-axis and the y-axis is parallel to the y-axis. In the present embodiment, a force F in the + Y direction received by the force receiving body 3A as a force from one direction is a detection target.

  As shown in FIG. 2, in the force detection device 1A, the fixed body 2A has a cylindrical portion whose center is located at the origin O. Also, the force receiver 3A has a rectangular frame-like portion arranged to surround the outer side thereof. The fixed body 2A is disposed at a space from the receiving body 3A. The force receiver 3A receives a force F in the + Y direction to be detected. In a state where the force F is not received, the center of the fixed body 2A (cylindrical portion) coincides with the center of the force receiving body 3A.

  Furthermore, the force detection device 1 </ b> A includes four deformable bodies 4. Each deformable body 4 is disposed between the fixed body 2A and the force receiving body 3A, and connects the fixed body 2A and the force receiving body 3A. More specifically, the deformable body 4 connects the outer side surface of the fixed body 2A and the inner side surface of the force receiving body 3A. In this force detection device 1A, as the deformable body 4, a first deformable body 4A disposed in the first quadrant of the XY two-dimensional coordinate system, a second deformable body 4B disposed in the second quadrant, and a third quadrant And a fourth deformable body 4D disposed in the fourth quadrant. Hereinafter, they are also referred to simply as the deformable bodies 4A, 4B, 4C, and 4D as appropriate.

  The first deformable body 4A includes a first protrusion 4Aa, a second protrusion 4Ab, and an extension 4Ac. Similarly, the second deformable body 4B includes a first projecting body 4Ba, a second projecting body 4Bb, and an extending body 4Bc, and the third deformable body 4C includes a first projecting body 4Ca. And the second protrusion 4Cb and the extension 4Cc, and the fourth deformable body 4D includes the first protrusion 4Da, the second protrusion 4Db, and the extension 4Dc. Prepare.

  The first protrusions 4Aa to 4Da are plate-like members that project toward the force receiving body 3A from the surface of the fixed body 2A facing the force receiving body 3A. The second protrusions 4Ab to 4Db are plate-like members that project toward the fixed body 2A from the surface of the force receiving body 3A facing the fixed body 2A. The extension members 4Ac to 4Dc are plate-like members connected to and extended from the tips of the first protrusions 4Aa to 4Db and the tips of the second protrusions 4Ab to 4Db. The extension members 4Ac to 4Dc extend along the circumference of a circle centered on the origin O.

  Thus, the four deformable bodies 4A to 4D are connected to the force receiving body 3A and the fixed body 2A, and the distance between the connection point with the force receiving body 3A and the connection point with the fixed body 2A is the force receiving body 3A. Are connected to the force receiving body 3A and the fixed body 2A so as to change in accordance with the force F received.

  Here, the first deformable body 4A and the second deformable body 4B are line symmetrical with the fourth deformable body 4D and the third deformable body 4C with the X axis as a symmetry axis, and the first deformable body 4A The fourth deformable body 4D is line symmetrical with the second deformable body 4B and the third deformable body 4C with the Y axis as a symmetry axis. That is, in the present embodiment, the center of the force receiving body 3A is the origin O, an axis along the direction of the force F received by the force receiving body 3A is Y, and an axis relating to the position where the force receiving body 3A receives When a two-dimensional orthogonal coordinate system is defined as the X axis, the facing relationship between the force receiving body 3A and the fixed body 2A is line symmetrical with respect to the Y axis and the X axis.

  Here, since the four extension members 4Ac, 4Bc, 4Cc, and 4Dc are thin plate-like members whose thicknesses in the radial direction centering on the origin O are smaller than those of the force receiving body 3A, the force receiving body 3A is Due to the force F in the + Y direction received, the elastic deformation is large. At the central portion of the extension members 4Ac, 4Bc, 4Cc, and 4Dc, there are formed raised portions that are slightly convex outward with respect to the origin O. Each of these raised portions is intended to facilitate the formation of the displacement electrode as described later, and is not necessary in the detection principle of the present invention.

  Of course, the force detection device 1A is an integral structure made of the same material, and if it is made of metal such as iron, stainless steel, or aluminum, for example, elastic deformation occurs in all parts by the action of the force F. It will be. However, the elastic deformation occurring in the fixed body 2A and the force receiving body 3A is small compared to the elastic deformation occurring in the deformable bodies 4A to 4D.

  The force detection device 1A includes four sets of detection bodies 5A to 5D as the detection means 5. These four sets of detection bodies 5A to 5D have a function of electrically detecting elastic deformation occurring in the deformable bodies 4A to 4D, and all of them are capacitive elements. That is, the detection bodies 5A to 5D are provided with electrostatic capacitance elements in which displacement electrodes formed on the outer side surfaces of the deformable bodies 4A to 4D and fixed electrodes formed on the inner side surface of the force receiving body 3A are opposed. ing. That is, the detection bodies 5A to 5D have electrostatic capacitance elements formed of electrodes provided facing the deformable bodies 4A to 4D and the force receiving body 3A. Due to the force F in the + Y direction, the deformable bodies 4A to 4D are elastically deformed, and the characteristic value (capacitance) of the capacitance element changes.

  Subsequently, the operation of the force detection device 1A shown in FIG. 1 will be described with reference to FIG. In addition, in fact, although the receiving body 3A is rectangular frame shape, in FIG. 3, in order to make an understanding of invention easy, the receiving body 3A is shown in circular frame shape.

  Displacement electrodes E11, E12, E13, and E14 are provided at four positions on the outer surface of the extension bodies 4Ac, 4Bc, 4Cc, and 4Dc, respectively, and a force-receiving member that opposes the displacement electrodes E11, E12, E13, and E14. Fixed electrodes F11, F12, F13, and F14 are provided at four places on the inner side surface of 3A.

  More specifically, the displacement electrode E11 is provided on the raised portion of the outer surface of the extension body 4Ac, and the fixed electrode F11 facing the displacement electrode E11 is provided on the opposing surface of the force receiving member 3A. The pair of electrodes (displacement electrode E11 and fixed electrode F11) constitute a capacitance element. The first detection body 5A is nothing but this capacitance element.

  Further, the displacement electrode E12 is provided on the raised portion of the outer side surface of the extension body 4Bc, the fixed electrode F12 is provided on the opposing surface of the force receiving body 3A, and the capacitance element to be the second detection body 5B is configured. Be done. Similarly, the displacement electrode E13 is provided on the raised portion of the outer surface of the extension body 4Cc, the fixed electrode F13 is provided on the opposing surface of the force receiving body 3A, and the capacitance element to be the third detection body 5C is configured. Be done. Further, the displacement electrode E14 is provided on the raised portion of the outer side surface of the extension body 4Dc, the fixed electrode F14 is provided on the opposing surface of the force receiving body 3A, and the capacitance element to be the fourth detection body 5D is configured. Be done.

  An insulating substrate is inserted between the protruding portions on the outer surface of the extension members 4Ac, 4Bc, 4Cc, 4Dc and the displacement electrodes E11 to E14, and between the force receiving body 3A and the fixed electrodes F11 to F14. Also the insulating substrate is inserted. In the present embodiment, the force detection device 1A is constituted by an integral structure made of metal, and it is necessary to electrically separate the individual electrodes. Therefore, when the force detection device 1A is made of an insulating material such as resin, it is not necessary to provide an insulating substrate.

  Here, in describing the detection operation of the force detection device 1A, for convenience, as shown in FIG. 3, the inner support points P1 and P2 which are connection points of the fixed body 2A and the deformable bodies 4A, 4B, 4C and 4D. , P3, P4, and outer supporting points Q1, Q2, Q3, Q4 which are connection points between the force receiving body 3A and the deformable bodies 4A, 4B, 4C, 4D.

  In the state where the fixed body 2A is fixed, as shown by the arrow in FIG. 3, when the force F in the + Y direction acts on the force receiving body 3A at the position of X = 0, the deformable bodies 4A, 4B, 4C. , Consider what kind of deformation occurs in 4D. In this case, the inner support points P1, P2, P3 and P4 are fixed points because they are connected to the fixed body 2A. On the other hand, since the outer support points Q1, Q2, Q3 and Q4 are connected to the force receiving body 3A, when the force Y in the + Y direction acts on the force receiving body 3A at the position of X = 0, the force It receives the action of F.

  Then, for example, since the point Q1 moves away from the point P1, the first deformable body 4A (the extending body 4Ac) deforms so as to be depressed radially inward. As a result, the displacement electrode E11 moves away from the fixed electrode F11, and the capacitance of the capacitive element (first detection body 5A) configured by both electrodes decreases. The amount of change in capacitance is C1. Similarly, since the point Q2 moves away from the point P2, the second deformable body 4B (the extension body 4Bc) also deforms so as to be depressed radially inward. As a result, the displacement electrode E12 moves away from the fixed electrode F12, and the capacitance of the capacitive element (second detection body 5B) configured by both electrodes decreases. Let C2 be the amount of change in capacitance.

  On the other hand, since the point Q3 moves so as to approach the point P3, the third deformable body 4C (the extending body 4Cc) deforms so as to expand radially outward. As a result, the displacement electrode E13 approaches the fixed electrode F13, and the capacitance of the capacitive element (third detection body 5C) configured by both electrodes increases. The amount of change in capacitance is C3. Further, since the point Q4 moves so as to approach the point P4, the fourth deformable body 4D (the extending body 4Dc) is deformed so as to expand radially outward. As a result, the displacement electrode E14 approaches the fixed electrode F14, and the capacitance of the capacitive element (fourth detection body 5D) configured by both electrodes increases. Let C4 be the amount of change in capacitance. The capacitance change amounts C1 to C4 are as shown in FIG.

  When the force in the -Y direction acts on the force receiving body 3A in a state in which the fixed body 2A is fixed, a motion opposite to the above occurs, and the variation amounts C1 to C4 of the electrostatic capacitance Indicates a change opposite to.

  As described above, in the detection unit 5, the plurality of detection bodies (electrostatic capacitance elements) 5A to 5D are disposed in each quadrant from the first quadrant to the fourth quadrant of the XY two-dimensional orthogonal coordinate system. The deformable bodies 4A to 4D are curved such that the position of one of the electrodes changes in accordance with the change in the distance between the fixed body 2A and the force receiving body 3A, and the capacitance changes due to the curvature. . The magnitude of the force F and the position receiving the force F can be detected based on the change amounts C1 to C4 of the capacitance.

  As shown in FIG. 1, a drive control unit 10 is connected to the force detection device 1A. The drive control unit 10 supplies power to the force detection device 1A and inputs the variation amounts C1 to C4 of the capacitances of the capacitance elements 5A to 5D, and the capacitances of the capacitance elements 5A to 5D. The calculation unit 6 as a part of the detection unit 5 that detects the magnitude of the force F and the position receiving the force F based on the change amounts C1 to C4 is provided.

The calculation unit 6 receives the variation amounts C1 to C4 of the capacitance, and calculates the magnitude of the force F based on the calculation result L1 of the following equation.
L1 = (C4-C1) + (C3-C2) (1)
There is a correlation between the calculation result L1 and the force F. If the calculation result L1 is obtained, the force F at that time can be obtained.

  For example, as shown in FIG. 4, when the force receiver 3A receives the force F in the + Y direction at the position of X = 0, C1 to C4 of the capacitance change amounts C1 to C4 of the capacitance elements 5A to 5D are obtained. , C2 decrease by -ΔC, C3 and C4 increase by + ΔC, and the magnitude of force F increases, C1 and C2 decrease, C3 and C4 increase, and calculation result L1 also increases . Conversely, if the calculation result L1 is determined, the magnitude of the force F can be determined from the correlation.

  In the above equation (1), the difference is between C4 and C1, but in the electrostatic capacitance element 5A and the electrostatic capacitance element 5D, the directions of the fixed body 2A and the power receiving body 3A are reversed. Therefore, in practice, this term corresponds to the sum of the amounts of change in the capacitances of the capacitance elements 5A and 5D in the first and fourth quadrants. Moreover, although it is a difference of C3 and C2 in said Formula (1), as for the electrostatic capacitance element 5B and the electrostatic capacitance element 5C, direction of the fixed body 2A and the receiving body 3A becomes reverse. In practice, this term corresponds to the sum of the amounts of change in the capacitances of the capacitance elements 5C and 5B in the third and second quadrants. Therefore, the above equation (1) corresponds to the sum of the amounts of change in capacitance of the capacitive elements 5A to 5D in the first, second, third and fourth quadrants.

Furthermore, the operation unit 6 uses the variation amounts C1 to C4 of the electrostatic capacitance elements 5A to 5D, and the X axis in which the force receiving member 3A receives the force F based on the calculation result L2 of the following equation. The upper position Δx (see FIG. 5) is detected.
L2 = (C2-C1) + (C4-C3) (2)
There is a correlation between the calculation result L2 and the position on the X axis receiving the force F, and using the calculation result L2, detection of the position Δx on the X axis on which the force receiving body 3A receives the force F it can.

  Here, the relationship between the position where the force receiver 3A receives the force F in the + Y direction and the calculation result L2 will be considered. As shown in FIG. 4, when the position receiving force F in the + Y direction is X = 0, C1 = C2 =-. DELTA.C, C3 = C4 = +. DELTA.C, so the calculation result L2 is 0, and the force is received. The position where the body 3A receives the force F in the + Y direction is detected as X = 0. On the other hand, as shown in FIG. 5, when the position receiving the force F in the + Y direction changes from X = 0 to X = Δx, the change amounts C1 to C4 of the electrostatic capacitance in the electrostatic capacitance elements 5A to 5D are The state shown in FIG. 4 changes to the state shown in FIG.

  As shown in FIG. 6, the capacitance change amount C1 decreases from -ΔC, the capacitance change amount C2 increases from -ΔC, and the capacitance change amount C3 decreases from ΔC. The change amount C4 of the capacity increases from ΔC. In this case, C2-C1 and C4-C3, which are terms of the calculation result L2, have positive values. As the Δx becomes larger, the value of the calculation result L2 becomes larger and monotonously increases. Therefore, if the correlation between the calculation result L2 and Δx is known in advance, it is possible to obtain the position Δx which receives the force F in the + Y direction based on the calculation result L2.

  In the above equation (2), the sum of (C2-C1) and (C4-C3) is calculated. This is because the electrostatic capacitive elements 5A and 5B and the electrostatic capacitive elements 5D and 5C have opposite directions of the fixed body 2A and the force receiving body 3A. This equation is based on the difference between the variation amounts C1 and C2 of the capacitances of the capacitance elements 5A and 5B in the first and second quadrants, and the static capacitance elements 5C and 5D in the third and fourth quadrants. It corresponds to the sum of the difference between the variation amounts C3 and C4 of the capacitance.

  Here, as shown in FIG. 7, the case where the force receiving body 3A receives a torque around the origin O (counterclockwise) will be considered. In this case, Q1-P1 and Q3-P3 become wide, and Q2-P2 and Q4-P4 become narrow. Therefore, as shown in FIG. 8, the change amounts C1 and C3 of the capacitances of the capacitance elements 5A and 5C decrease to -.DELTA.C, and the change amount C2 of the capacitances of the capacitance elements 5B and 5D. , C 4 increase to ΔC, but the calculation result L 1 of the above equation (1) becomes 0. Therefore, the force F can be detected in the state where the component of the torque around the origin O is removed by using the above equation (1).

  Thus, detection using the plurality of electrostatic capacitance elements 5A to 5D is effective in reducing detection errors. For example, expansion or contraction occurs in each part of the force detection device 1A due to a change in temperature environment, and the electrode detection of each of the electrostatic capacitance elements 5A to 5D changes the above difference detection. Errors that occur based on changes in spacing can be offset.

  As described above in detail, according to the present embodiment, the force receiving body 3A and the fixed body 2A are arranged in the X axis direction that intersects the direction of the force F received by the force receiving body 3A (Y axis direction). Position of the force F is applied based on the difference between the change amounts C1 to C4 of the capacitances. Can be detected.

  Further, according to the present embodiment, displacement electrodes E11 to E14 of capacitance elements 5A to 5D are provided on deformable bodies 4A to 4D. In the deformable bodies 4A to 4D, the force receiving body 3A and the fixed body are changed such that the distance between the connection point with the force receiving body 3A and the connection point with the fixed body 2A changes according to the force received by the force receiving body 3A. It is connected to 2A, and is curved so that the position of one of the electrodes (displacement electrodes E11 to E14) changes according to the change in the distance between the connection points. With such a configuration, the displacement of the displacement electrodes E11 to E14 can be increased by the curvature of the deformable bodies 4A to 4D. As a result, since the change amounts C1 to C4 of the electrostatic capacitance elements 5A to 5D can be increased, the sensitivity of the force detection device 1A is increased, and the detection accuracy of the position to which the force F is applied is high. can do.

  In the detection means 5, one displacement electrodes E11 to E14 of the electrostatic capacitance elements 5A to 5D are provided on the deformable bodies 4A to 4D, and the other fixed electrodes F11 to F14 of the electrostatic capacitance elements 5A to 5D are Although provided on the force receiving body 3A, the other fixed electrodes F11 to F14 may be provided on the fixed body 2A.

  In the detection means 5, a plurality of electrostatic capacitance elements 5A to 5D are arranged along the direction of the force received by the force receiving body 3A. Thus, the number of pieces of information for detecting the position of the force F can be increased, so that the position of the force F can be detected with high accuracy.

Embodiment 2
Next, a second embodiment of the present invention will be described in detail with reference to the drawings.

  As shown in FIG. 9, the force detection device 1 </ b> B according to the present embodiment has a rectangular flat plate shape as a whole. The force detection device 1B mainly includes the fixed body 2B and the force receiver 3B, and the fixed body 2B, the force receiver 3B, and the cover KC form the entire outer shape of the force detection device 1A. As shown in FIGS. 9 (A), 9 (B) and 9 (C), the fixed body 2B and the force receiving body 3B are combined in the z-axis direction to constitute a force detection device 1B.

  The fixed body 2B is disposed at a space from the force receiving body 3B, and the force receiving body 3B is held by a member different from an external member fixed to the fixed body 2B. The cover KC covers a part of the fixed body 2B and the force receiving body 3B. The force receiver 3B is fixed to the cover KC, and receives the force F in the + Y-axis direction to be detected through the cover KC. On the other hand, the fixed body 2B is not fixed to the cover KC. For this reason, by holding the fixed body 2B and the cover KC (the force receiving body 3B) on separate external members, the force receiving body 3B is in the xy plane in a predetermined range with respect to the fixed body 2B. It is possible to move up. When the force F is not received, the center of the fixed body 2B and the center of the force receiving body 3B coincide with each other at the origin O.

  In the force detection device 1B, the deformable body 4 (4A to 4D) is not provided. On the other hand, in the force detection device 1B, the fixed body 2B is provided with protrusions 2Ba to 2Bd that project toward the force receiving body 3B (in the + z direction). Further, the force receiving body 3B is provided with a protrusion 3Ba that protrudes toward the fixed body 2B (in the -z direction). As shown in FIG. 10, the protrusions 2Ba to 2Bd and the protrusions 3Ba are arranged to face each other in the Y-axis direction. In the force detection device 1B, the detection bodies 5A to 5D as the detection means 5 are provided between the protrusions 2Ba to 2Bd and the protrusion 3Ba.

  Fixed electrodes (second electrodes) F11, F12, F13, and F14 are provided on the side surfaces of the protrusions 2Ba to 2Bd, respectively. The protrusion 3Ba is provided with displacement electrodes (first electrodes) E11, E12, E13, E14 so as to face the fixed electrodes (second electrodes) F11, F12, F13, F14. That is, in the force detection device 1B, one displacement electrode E11, E12, E13, E14 of the electrostatic capacitance elements 5A to 5D is provided on the receiving body 3B, and the other fixed electrode F11 of the electrostatic capacitance elements 5A to 5D. , F12, F13, and F14 are provided on the fixed body 2B. Therefore, electrostatic capacitance element 5A is formed of displacement electrode E11 and fixed electrode F11, electrostatic capacitance element 5B is formed of displacement electrode E12 and fixed electrode F12, and electrostatic capacitance element 5C is formed of displacement electrode E13 and fixed electrode F13. The electrostatic capacitance element 5D is configured by the displacement electrode E14 and the fixed electrode F14.

  In a state where the fixed body 2B is fixed, when a force in the + Y direction acts on the force receiving body 3B, the displacement electrode E11 moves so as to approach the fixed electrode F11, and a capacitive element configured by both electrodes The amount of change in capacitance C1 of (the first detection body 5A) increases. Similarly, the displacement electrode E12 moves so as to approach the fixed electrode F12, and the change amount C2 of the electrostatic capacitance of the electrostatic capacitance element (second detection body 5B) configured by both electrodes increases.

  On the other hand, the displacement electrode E13 moves away from the fixed electrode F13, and the change amount C3 of the electrostatic capacitance of the electrostatic capacitance element (third detection body 5C) constituted by both electrodes decreases. Similarly, the displacement electrode E14 moves away from the fixed electrode F14, and the variation C4 of the electrostatic capacitance value of the electrostatic capacitance element (fourth detection body 5D) constituted by both electrodes decreases.

  When the force in the -Y direction acts on the force receiving body 3B in a state where the fixed body 2B is fixed, a motion opposite to the above occurs, and the variation amounts C1 to C4 of the electrostatic capacitance Indicates a change opposite to.

  Also in the present embodiment, in the detection means 5, the plurality of electrostatic capacitance elements 5A to 5D are respectively disposed in each quadrant from the first quadrant to the fourth quadrant of the XY two-dimensional orthogonal coordinate system. The calculation unit 6 detects the magnitude and the position of the force F based on the change amounts C1 to C4 of the capacitances of the capacitance elements 5A to 5D.

The calculation unit 6 inputs the variation amounts C1 to C4 of the capacitance, and calculates the magnitude of the force F based on the calculation result L3 of the following equation.
L3 = (C1-C4) + (C2-C3) (3)
There is a correlation between the calculation result L3 and the force F, and if the calculation result L3 is obtained, the force F at that time can be obtained.

  For example, when force receiver 3B receives force F in the + Y direction at X = 0, capacitance changes C1 to C4 of capacitance elements 5A to 5D are C1 and C2, as shown in FIG. Increases by ΔC, and C3 and C4 decrease by −ΔC. As the magnitude of the force F increases, C1 and C2 increase, C3 and C4 decrease, and the calculation result L3 also increases. Therefore, if the calculation result L3 is used, the magnitude of the force F can be obtained from the correlation.

  In addition, although the said Formula (3) includes the term of the difference of C1 and C4, as for electrostatic capacitance element 5A and electrostatic capacitance element 5D, direction of fixed body 2B and power receiving body 3B is reverse. In fact, this term corresponds to the sum of the amount of change in the capacitances of the capacitance elements 5A and 5D in the first and fourth quadrants. Moreover, although the said Formula (3) includes the term of the difference of C2 and C3, as for electrostatic capacitance element 5B and electrostatic capacitance element 5C, direction of fixed body 2B and power receiving body 3B is reverse. In fact, this term corresponds to the sum of the amount of change in the capacitances of the capacitive elements 5C and 5B in the third and second quadrants. Therefore, the above equation (3) corresponds to the sum of the amounts of change in capacitance of the capacitance elements 5A to 5D in the first, second, third and fourth quadrants.

Furthermore, the calculation unit 6 uses the variation amounts C1 to C4 of the electrostatic capacitance elements 5A to 5D, and the X axis in which the force receiving member 3B receives the force F based on the calculation result L4 of the following equation. The upper position Δx (see FIG. 12) is detected.
L4 = (C1-C2) + (C3-C4) (4)
Since there is a correlation between the calculation result L4 and the position on the X axis receiving the force F, using the calculation result L4, the position Δx on the X axis on which the force receiving member 3B receives the force F is detected. Can.

  Here, the relationship between the position where the force receiver 3B receives the force F in the + Y direction and the calculation result L4 will be considered. As shown in FIG. 11, when the position receiving force F in the + Y direction is X = 0, C1 = C2 = ΔC, C3 = C4 = −ΔC, so the calculation result L4 is 0, and the force is received. The position where the body 3B receives the force F in the + Y direction is detected as X = 0. On the other hand, when the position receiving force F in the + Y direction changes from X = 0 to X = Δx, the change amounts C1 to C4 of the capacitances of the capacitance elements 5A to 5D are as shown in FIG. , Changes to the state shown in FIG.

  That is, the change amount C1 of capacitance increases from ΔC, the change amount C2 of capacitance decreases from ΔC, the change amount C3 of capacitance increases from -ΔC, and the change amount C4 of capacitance Decrease from -ΔC. Thereby, C1-C2 and C3-C4 turn into a positive value. As the Δx becomes larger, the value of the calculation result L4 becomes larger. Therefore, based on the calculation result L4, it is possible to obtain the position Δx which receives the force F in the + Y direction.

  In addition, in said Formula (4), the sum of (C1-C2) and (C3-C4) is calculated. This is because the directions of the fixed body 2B and the force receiving body 3B are reversed in the electrostatic capacitance elements 5A, 5B and the electrostatic capacitance elements 5D, 5C. This equation is based on the difference between the variation amounts C1 and C2 of the capacitances of the capacitance elements 5A and 5B in the first and second quadrants, and the static capacitance elements 5C and 5D in the third and fourth quadrants. It corresponds to the sum of the difference between the variation amounts C3 and C4 of the capacitance.

  As described above, according to the present embodiment, one displacement electrodes E11 to E14 of capacitance elements 5A to 5D are provided on force receiver 3B, and the other of capacitance elements 5A to 5D is fixed Electrodes F11 to F14 are provided on the fixed body 2B. In this way, since it is not necessary to provide the deformable bodies 4A to 4D, it is possible to reduce the number of parts, simplify the apparatus configuration, reduce the occurrence of failure, and extend the life of the apparatus.

Third Embodiment
Next, a third embodiment of the present invention will be described in detail with reference to the drawings.

  As shown in FIG. 13, the present embodiment is different from the above-described embodiment in that a connecting body 7 for connecting the fixed body 2 </ b> C and the power receiving body 3 </ b> C is provided. Further, in the force detection device 1C according to the present embodiment, the first deformable body 4A ′ and the first detection body 5A are provided in the first quadrant, and the second deformable body 4B ′ and the second deformation body in the second quadrant. Detection body 5B is provided, the third deformation body 4C 'and the third detection body 5C are provided in the third quadrant, and the fourth deformation body 4D' and the fourth detection body 5D are provided in the fourth quadrant. It is done. In the present embodiment, the shapes of the first deformation body 4A ′ to the fourth deformation body 4D ′ and the directions of the first detection body 5A to the fourth detection body 5D are different from those of the first embodiment. There is.

  In the first deformable body 4A ′ to the fourth deformable body 4D ′, the first protrusions 4Aa ′ to 4Da ′ connected with the fixed body 2C and the second protrusions 4Ab ′ ̃ connected with the force receiver 3C. 4Db 'extends in the X-axis direction, and the extension members 4Ac' to 4Dc 'extend in the Y-axis direction.

  As shown in FIG. 14, when the force receiver 3C receives the force F in the + Y axis direction at the position of X = 0, the first deformable body 4A ′ and the second deformable body 4B ′ deform and the fixed body 2C. The distance in the Y-axis direction between the connection point of and the connection point of the force receiver 3C is increased. Thus, as shown by the arrows, the displacement electrodes E11 and E12 move away from the fixed electrodes F11 and F12 and shift in the −Y direction. Therefore, the change amounts C1 and C2 of the capacitances of the capacitance elements 5A and 5B configured by the both electrodes decrease.

  Further, the third deformable body 4C 'and the fourth deformable body 4D' are deformed, and the distance in the Y-axis direction between the connection point of the fixed body 2C and the connection point of the force receiving body 3C becomes short. As a result, as indicated by the arrows, the displacement electrodes E13 and E14 approach the fixed electrodes F13 and F14 and are displaced in the + Y direction. Therefore, the change amounts C3 and C4 of the capacitances of the capacitance elements 5C and 5D configured by both electrodes increase.

  Further, as shown in FIG. 15, consider the case where the force receiver 3C receives the force F in the + Y-axis direction at X = Δx. In this case, with respect to the first deformable body 4A 'and the fourth deformable body 4D', the vectors indicating the moving amounts of the displacement electrodes E11 and E14 become larger. On the other hand, with respect to the second deformable body 4B 'and the third deformable body 4C', the vectors indicating the moving amounts of the displacement electrodes E12 and E13 are smaller than those in FIG.

  As described above, the magnitudes of the force F and the variations C1 to C4 of the capacitance change of the capacitance elements 5A to 5D with respect to the position Δx are similar to those of the first embodiment. Therefore, as in the first embodiment, the magnitude and the position Δx of the force F can be detected from the variation amounts C1 to C4 of the electrostatic capacitance by using the equations (1) and (2).

  In the present embodiment, when force F is applied, displacement electrodes E11 to E14 move closer to or away from fixed electrodes F11 to F14 and are displaced in the Y-axis direction to form fixed electrodes F11 to F14. The overlapping area also changes. By this area change, it is also possible to increase the inclination of the change in capacitance and to improve the detection sensitivity.

  As described above, in the force detection devices 1A, 1B, and 1C according to the above-described embodiments, the centers of the force receiving members 3A, 3B, and 3C are the origin O, and the force receiving members 3A, 3B, and 3C receive When a two-dimensional orthogonal coordinate system is defined in which the axis along the direction is Y axis and the axis about the position where the force receiving members 3A, 3B, 3C receive the force F is X axis, the force receiving members 3A, 3B, 3C The facing relationship between the fixed bodies 2A, 2B and 2C is axisymmetric with respect to the Y axis and the X axis, and in the detecting means 5, the plurality of capacitive elements 5A to 5D are from the first quadrant of the XY two-dimensional orthogonal coordinate system. It is disposed in each quadrant up to the fourth quadrant. When the force receiving members 3A, 3B, 3C receive a force moving from the third quadrant to the second quadrant or a force moving from the fourth quadrant to the first quadrant, the computing unit 6 of the detection means 5 Difference in the amount of change in capacitance of electrostatic capacitance elements 5A to 5D in the first quadrant and the second quadrant, and difference in amount of change in capacitance of electrostatic capacitance elements 5A to 5D in the third quadrant and fourth quadrant And the position .DELTA.x of the force received by the force receiving members 3A, 3B, 3C is calculated. Further, the calculation unit 6 calculates the magnitude of the force F based on the sum of the change amounts of the capacitances of the capacitance elements 5A to 5D in the first, second, third, and fourth quadrants.

The polarities of the capacitance change amounts C1 to C4 of the electrostatic capacitance elements 5A to 5D appropriately change according to the directions of the fixed bodies 2A to 2C and the force receiving bodies 3A to 3C in the quadrant. When the directions of the fixed body and the force receiving body are the same in all the quadrants, the magnitude of the force F is detected using the following calculation result L5, and the force F is applied using the following calculation result L6. The detected position Δx is detected.
L5 = (C4 + C1) + (C3 + C2) (5)
L6 = (C1-C2) + (C4-C3) (6)

  The present invention is capable of various embodiments and modifications without departing from the broad spirit and scope of the present invention. In addition, the embodiment described above is for explaining the present invention, and does not limit the scope of the present invention. That is, the scope of the present invention is indicated not by the embodiments but by the claims. And, various modifications applied within the scope of the claims and the meaning of the invention are considered to be within the scope of the present invention.

  The present invention can be applied to detect the position where a force in one direction is applied.

  1A, 1B, 1C force detection device, 2A, 2B, 2C fixed body, 2Ba, 2Bb, 2Bc, 2Bd protrusion, 3A, 3B, 3C force receiver, 3Ba protrusion, 4 deformable body, 4A, 4A 'first Deformation of 4Aa, 4Aa 'first projection, 4Ab, 4Ab' second projection, 4Ac, 4Ac 'extension, 4B, 4B' second deformation, 4Ba, 4Ba 'first projection Body, 4Bb, 4Bb 'second protrusion, 4Bc, 4Bc' extension, 4C, 4C 'third variant, 4Ca, 4Ca' first protrusion, 4Cb, 4Cb 'second protrusion, 4Cc, 4Cc 'extension, 4D, 4D' fourth variant, 4Da, 4Da 'first projection, 4Db, 4Db' second projection, 4Dc, 4Dc 'extension, 5 detection means, 5A first detector (capacitive element), 5B second Detection body (electrostatic capacitance element), 5C third detection body (electrostatic capacitance element), 5D fourth detection body (electrostatic capacitance element), 6 arithmetic unit, 7 connector, 10 drive control unit, E11, E12, E13, E14 Displacement electrode, F11, F12, F13, F14 Fixed electrode, F force, KA, KB, KC cover, P1, P2, P3, P4 Inner support point, Q1, Q2, Q3, Q4 Outer support point

Claims (8)

A fixed body to be fixedly arranged,
A receiving body that receives a force from one direction to be detected;
It has a plurality of electrostatic capacitance elements which are arranged in a direction intersecting with the direction of the force received by the force receiving body and whose capacitance varies in accordance with the relative displacement between the force receiving body and the fixed body, A detection unit that detects a position at which the force receiving member receives a force based on a difference in change in capacitance of the capacitance element;
Force detection device comprising: And a deformable body connected between the force receiving body and the fixed body and deformed according to a force received by the force receiving body.
In the detection means,
One electrode of the capacitive element is provided on the deformable body,
The other electrode of the capacitive element is provided on the force receiving body or the fixed body,
The force detection device according to claim 1. The deformation body is
The distance between the connection point with the force receiving body and the connection point with the fixed body is connected to the force receiving body and the fixed body so as to change according to the force received by the force receiving body.
It is curved so that the position of the one electrode changes in accordance with the change in the distance between the connection points.
The force detection device according to claim 2. One electrode of the capacitive element is provided on the force receiving body,
The other electrode of the capacitive element is provided on the fixed body,
The force detection device according to claim 1. In the detection means,
A plurality of the capacitive elements are arranged along the direction of the force received by the receiving body,
The force detection device according to any one of claims 1 to 4. A two-dimensional orthogonal coordinate system is defined in which the center of the force receiving body is the origin, the axis along the direction of the force received by the force receiving body is the ordinate, and the position where the force receiving body receives the force is the abscissa. In case,
The facing relationship between the force receiving body and the fixed body is axisymmetric with respect to the vertical axis and the horizontal axis,
In the detection means,
The plurality of capacitive elements are disposed in each of the first quadrant, the second quadrant, the third quadrant, and the fourth quadrant of the two-dimensional orthogonal coordinate system.
The force detection device according to claim 5. The force receiving body receives a force from the third quadrant to the second quadrant or a force from the fourth quadrant to the first quadrant,
The detection means
The difference in the amount of change in capacitance of the capacitance element in the first quadrant and the second quadrant, and the difference in the amount of change in capacitance in the capacitance element in the third quadrant and the fourth quadrant, And a calculating unit that calculates the position of the force received by the force receiving body based on
The force detection device according to claim 6. The arithmetic unit is
The magnitude of the force is calculated based on the sum of the change amounts of the capacitances of the capacitance elements in the first, second, third and fourth quadrants.
The force detection device according to claim 7.

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