JPH06210585A - Spherical actuator - Google Patents

Abstract

PURPOSE:To provide a miniature and lightweight spherical actuator which can detect and control a rotating angle of a spherical body with a high degree of accuracy, and which can cope with a rotating angle of the spherical body. CONSTITUTION:A spherical shell-like spherical body 1 is rotatably supported by a support member 6. Two bendable elements incorporating strain gages 3a, 3b, and leaf springs 2a, 2b; 4a, 4b are connected at their ends with each other so that their bending directions are orthogonal to each other. Further, the connected bendable elements 2, 4 are stored in the spherical body, the free end of the bendable element 2 are secured and connected to the top part of the inner surface of the spherical body 1, while the free end of the bendable element 4 is secured and connected to the support member 6. When the spherical body 1 is rotated, the bendable elements 2, 4 are bent so that the degrees of bending thereof are detected by the strain gages 3a, 3b, thereby it is possible to detect a rotating angle of the spherical body 1.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to spherical actuators. More specifically, the present invention relates to a technique for detecting a rotation angle of a spherical body in a spherical actuator that rotatably supports the spherical body.

[0002]

2. Description of the Related Art In a spherical actuator in which a spherical shell-shaped spherical body is rotatably supported by a supporting member, it is necessary to detect the rotational angle of the spherical body with high accuracy in order to control the rotational angle of the spherical body with high accuracy. There is.

A conventional rotation angle detecting method for a spherical actuator is disclosed in Japanese Patent Laid-Open No. 62-228392. This is because a point light source such as a light emitting diode is fixed to a part of the rotating spherical body (center of the spherical body) so that the positional relationship with the support member that rotatably supports the spherical body becomes constant. In this method, the position of the point light source is detected by a monitor camera fixed to and the rotational position corresponding to the latitude and longitude of the rotating spherical body is detected by image processing by the camera.

[0004]

However, in such a conventional method, since the ideal point light source does not exist or the pixel resolution of the monitor camera is limited, the accuracy of detecting the rotation angle of the spherical body is reduced. There was a problem of low. Further, since one point light source cannot cope with a rotation angle of 180 ° or more, it is impossible to detect a rotation angle of 180 ° or more. further,
Since a monitor camera is required, when the spherical actuator is used for a robot joint, a manipulator, etc., the robot joint, the manipulator, etc. have the drawbacks of increased size and weight and a complicated structure.

The present invention has been made in view of the drawbacks of the above-mentioned conventional examples, and the object thereof is to cope with a rotation angle of 180 ° or more and to detect the rotation angle of a spherical body with high accuracy. It is to provide a spherical actuator that is small, lightweight, and has a simple structure.

[0006]

According to a first spherical actuator of the present invention, in a spherical actuator in which a spherical body is rotatably supported, two bending elements to which a strain detector is attached are bent in mutually different directions. It is characterized in that they are connected so as to be orthogonal to each other, and one end portion of the two connected bending elements is fixed to the inner surface of the spherical body, and the other end portion is fixed to a stationary portion other than the spherical body.

According to a second spherical actuator of the present invention, in a spherical actuator in which a spherical body is rotatably supported, the bottom of the spherical body is cut out to form a notch, and the spherical body is opposed to the bottom of the spherical body. It is characterized in that electrodes are respectively arranged in two orthogonal directions and a capacitance is formed between each of the electrodes and the spherical body.

The third spherical actuator of the present invention is a spherical actuator in which a spherical body is rotatably supported, and at least one magnet is provided on the inner surface of the spherical body so that the magnetic flux passes through substantially the center of rotation of the spherical body. At least two magnetic flux detectors whose mounting and detecting surfaces are orthogonal to each other are arranged at substantially the center of rotation of the spherical body.

In the third spherical actuator, the magnet may be an electromagnet.

A fourth spherical actuator of the present invention is a spherical actuator in which a spherical body is rotatably supported, and a projection portion is provided on the spherical body, and a pair of positions having a slot having a width substantially equal to that of the projection portion. Each of the detection plates is rotatably supported near the spherical body, and angle detection means for detecting the rotation angle of each position detection plate is provided, and the protrusion is formed in both elongated holes at the intersection of both position detection plates. The feature is that it is slidably inserted.

In the fourth spherical actuator, the position detecting plate is formed in an arc shape along the surface of the spherical body, and is coaxial with a pair of drive stators for rotationally driving the spherical body. You may arrange | position a pair of said angle detection means, and each position detection plate may be rotatably supported by each position detection means.

[0012]

In the first spherical actuator of the present invention, when the spherical body is rotated, one or both of the two bending elements are bent depending on the rotation direction and the rotation angle of the spherical body. To do. Since the bending degree of these bending elements can be detected by the respective strain detectors, the rotation direction and the rotation angle of the spherical body can be detected by detecting the bending degree of each bending element.

Further, in the second spherical actuator of the present invention, since the electrodes are arranged so as to face the notches of the spherical body, when the spherical body rotates, the static electricity between each electrode and the spherical body is reduced. The capacitance changes. Therefore, the rotation direction and the rotation angle of the spherical body can be detected by detecting the electrostatic capacitance between each electrode and the spherical body.

Further, in the third spherical actuator of the present invention, the magnetic flux is generated by the magnet attached to the inner surface of the spherical body, and the magnetic flux passing through each magnetic flux detector is detected by the plurality of magnetic flux detectors. Therefore, when the spherical body rotates, the magnetic flux passing through each magnetic flux detector changes. Therefore,
The rotation direction and rotation angle of the spherical body can be detected by the output of each magnetic flux detector.

Further, in the fourth spherical actuator of the present invention, the pair of position detecting plates are rotatably supported near the spherical body, and the protrusion of the spherical body is formed at the intersection of both the position detecting plates. As the spherical body rotates, the position detecting plate is forcibly rotated by the protrusions, respectively, according to the rotation direction and the rotation angle of the spherical body. The position detection plate rotates. Therefore, the rotation direction and the rotation angle of the spherical body can be detected by detecting the rotation angle of the position detection plate by the angle detection means.

[0016]

1 is a sectional view showing a spherical actuator A according to a first embodiment of the present invention. In the spherical actuator A, a spherical member 1 having a spherical shell shape is rotatably supported by a supporting member 6. A spherical shell-shaped spherical body 1 has a cavity 1a inside and has a bottom portion cut open by a flat surface, and a shaft portion 1b for attaching an output portion such as an arm is protrudingly provided on the outer surface zenith portion. Has been done. The support member 6 is
It is curved along the outer surface of the spherical body 1, and is formed in, for example, a cross shape so as not to hinder the rotation of the spherical body 1 having the shaft portion 1b. Further, the support member 6 is provided with drive systems such as piezoelectric elements (not shown) along the two orthogonal directions. When these drive systems are driven, the spherical body 1 is driven by the same principle as the ultrasonic motor. Can be rotated at any angle in any rotation direction. In addition, spherical body 1
The rotation direction and the rotation angle can be detected by the two plate-shaped bending elements 2 and 4 provided with the strain gauges 3a and 3b.

FIGS. 2A and 2B show one bending element 2, 4
FIG. 3 is a perspective view and a side view showing the two leaf springs 2a,
2b; 4a and 4b are blocks 5a and 5 having relatively high rigidity
They are connected in parallel at b, and strain gauges 3a and 3b are attached to the surfaces of the blocks 5a and 5b. The two bending elements 2 and 4 are welded and fixed by making the ends of the leaf springs 2b and 4b orthogonal to each other. That is, they are connected so that their bending directions are orthogonal to each other. The connected bending elements 2 and 4 are housed in the center of the cavity 1a of the spherical body 1, and the end of the leaf spring 2a of one bending element 2 is fixedly connected to the inner surface zenith of the spherical body 1. And the end of the leaf spring 4a of the other bending element 4 is fixedly connected to the support member 6 and arranged so that the midpoint of the connection between the leaf springs 2b and 4b is located at the rotation center P of the spherical body 1. Has been done.
The outputs of the strain gauges 3a and 3b of the two bending elements 2 and 4 can be individually detected.

4 (a), (b), (c) and (d) show the rotation angles θX, θY of the spherical body 1 in the spherical actuator A.
FIG. 3 is a schematic cross-sectional view showing the principle of detecting the bending angle, in which the bending direction of one bending element 2 is in the XZ plane and the bending direction of the other bending element 4 is in the YZ plane. The spherical body 1 located at the initial position (reference position) as shown in FIG.
When rotating about the X axis by θX as in (b), the bending element 2 is less likely to be deformed in the YZ plane, so that the output of the strain gauge 3a of the bending element 2 is relative to the longitudinal direction of the bending element 2. Can be ignored. On the other hand, when the spherical body 1 rotates around the X axis, the bending element 4 deforms in the YZ plane and the strain gauge 3b expands and contracts in the longitudinal direction of the bending element 4, so that the strain gauge 3b strains the bending element 4. Generates output according to the amount.
Since there is a fixed relationship between the rotation angle θ _X of the spherical body 1 and the strain amount ε _X of the bending element 4, for example, a linear relationship as shown in FIG. If the amount ε _X is detected, the rotation angle θ X of the spherical body 1 about the X axis can be known from the strain amount ε _X. It should be noted that FIG. 3 is a graph showing that there is a linear relationship between the rotation angle θ _X of the spherical body 1 and the strain amount ε _X of the bending element 4, and it is considered that a nonlinear element is actually included, so correction is necessary. Needless to say.

Similarly, the spherical body 1 located at the reference position as shown in FIG. 4 (c) is rotated about the Y axis by θY as shown in FIG. 4 (d).
When the bending element 4 is rotated by only, the bending element 4 does not easily deform in the XZ plane, so that the output of the strain gauge 3b of the bending element 4 can be ignored in the longitudinal direction of the bending element 4. On the other hand, when the spherical body 1 rotates around the Y axis, the bending element 2 deforms in the XZ plane, and the strain gauge 3a expands and contracts in the longitudinal direction of the bending element 2, so that the strain gauge 3a strains the bending element 2. Generate an output according to the quantity ε _Y. Since the rotation angle θ _Y of the spherical body 1 and the strain amount ε _Y of the bending element 2 have the same fixed relationship as in FIG. 3, for example, if the strain amount ε _Y of the bending element 2 is detected by the strain gauge 3a. From the strain amount ε _Y, the rotation angle θ Y about the Y axis of the spherical body 1 can be known.

Therefore, the rotation direction and the rotation angles θX and θY of the spherical body 1 can be detected with high accuracy from the outputs of the strain gauges 3a and 3b of the two bending elements 2 and 4. Further, the mechanism for detecting the rotation angle of the spherical body 1 can be simplified, and the size and weight can be reduced. In addition, spherical body 1
By increasing the opening area of the bottom of the spherical body 1, the rotation angle of the spherical body 1 can be increased, and a rotation angle of 180 ° or more is also possible.

FIGS. 5 (a) and 5 (b) are schematic front views showing a spherical actuator B according to the second embodiment of the present invention and its operation with a part thereof omitted. Also in this spherical actuator B, the spherical body 1 is rotatably supported by an appropriate supporting member (not shown). The spherical body 1 is formed of a conductor such as metal into a substantially solid spherical shape, and the lower bottom surface of the spherical body 1 is cut out in a plane shape. Two sets of electrodes 7, 9; 8, 10 are arranged below the plane cutout surface 1c so as to be orthogonal to each other, and between the spherical body 1 and each electrode 7, 8, 9, 10. Capacitance is configured in. For example, each of the electrodes 7, 8, 9 and 10 may be curved so as to be concentric with the spherical portion of the spherical body 1,
These electrodes 8, 1 may be formed in a planar shape.
0; 7, 9 are arranged along the positive and negative directions of the X axis and the positive and negative directions of the Y axis, and the electrodes 7, 8, 9, 10 and the spherical body 1 are insulated by an air gap or an insulating film. is doing. The electrodes 7, 8, 9 and 10 are arranged so that when the rotation angles θX and θY of the spherical body 1 are 0, the overlap with the spherical portion of the spherical body 1 is almost 0.

FIG. 6 is a view showing a measuring circuit C for detecting the electrostatic capacitance between each electrode 7, 8, 9, 10 and the spherical body 1 when the spherical actuator B is viewed from the lower surface side. . This measuring circuit C includes two sets of bridge circuits 16a and 16a.
It is configured on the basis of b. One bridge circuit 1
6a is a resistor 12a, a resistor 15b and a capacitor 11
The series connection body of b is made to oppose, and the series connection body of the resistor 15a and the capacitor 11a is made to oppose, and the middle point of the resistances 12a and 12b,
A current limiting resistor 1 is provided at the midpoint of the series connection (resistor 15a and capacitor 11a; resistor 15b and capacitor 11b).
An AC power supply 13 is connected via 4. Similarly, the other bridge circuit 16b includes a resistor 12c and a resistor 15d.
And a series connection body of the capacitor 11d and a resistor 12d and a series connection body of the resistor 15c and the capacitor 11c are faced to each other.
An alternating current power supply 13 is connected to the middle point of 12 and 12d and the middle point of the series connection body (resistor 15c and capacitor 11c; resistor 15d and capacitor 11d) via the same current limiting resistor 14.

The middle point of the resistor 15c and the capacitor 11c is connected to the electrode 7, and the resistor 15a and the capacitor 11a are connected.
The middle point is connected to the electrode 8, the resistor 15d and the capacitor 1
The midpoint of 1d is connected to the electrode 9, the midpoint of the resistor 15b and the capacitor 11b is connected to the electrode 10, and
The bridge circuits 16 a and 16 b of the current limiting resistor 14 are electrically connected to the spherical body 1. Therefore, the capacitance C7 between the electrode 7 and the spherical body 1 is in parallel with the capacitor 11c, the capacitance C8 between the electrode 8 and the spherical body 1 is in parallel with the capacitor 11a, and the electrode 9 and the spherical surface are Capacitance C9 between body 1 is in parallel with capacitor 11d,
The capacitance C10 between 0 and the spherical body 1 is in parallel with the capacitor 11b. Therefore, the capacitance C7 between the electrode 7 and the spherical body 1 is represented by the capacitor 17c, and the capacitance C8 between the electrode 8 and the spherical body 1 is represented by the capacitor 17a.
The capacitance C9 between the electrode 9 and the spherical body 1 is changed to the capacitor 17
When the electrostatic capacitance C10 between the electrode 10 and the spherical body 1 is represented by a capacitor 17b, the measuring circuit C of the spherical actuator B is represented by an equivalent circuit as shown in FIG.
In FIG. 7, ZC7, ZC8, ZC9 and ZC10 are spherical bodies 1
Between each of the electrodes 7, 8, 9, 10 and C7, C8,
Impedance due to C9 and C10. In the bridge circuit 16a, the a terminal and the b terminal for detection are taken out from the middle point of the resistors 12a and 15a and the middle point of the resistors 12b and 15b, respectively. Similarly, in the bridge circuit 16b, the c terminal and the d terminal for detection are taken out from the midpoints of the resistors 12c and 15c and the midpoints of the resistors 12d and 15d, respectively.

The bridge circuits 16a, 16 on the measuring side
In b, the resistors 15a, 15b, 15c and 15d and the capacitors 11a, 11b, 11c and 11d are connected in series, and the capacitors 17a, 17b, 17c and 17d between the electrodes 7, 8, 9 and 10 and the spherical body 1 are connected. Capacitor 1
Connected in parallel with 1a, 11b, 11c, 11d is
Capacitors 17a, 17b on the side of electrodes 7, 8, 9, 10;
Since 17c and 17d correspond to air capacitors and are minute, the capacitors 17a, 17b, 17c and 17d are rotated by the rotation of the spherical body 1 in order to improve the stability of measurement.
The purpose is to compensate when the electrostatic capacitances C7, C8, C9, and C10 of 0 become 0.

Next, the principle of detecting the rotation angle of the spherical body 1 by the measuring circuit C as shown in FIGS. 6 and 7 will be described. It is assumed that the spherical actuator B as shown in FIG. 5A is rotated by θX around the X axis as shown in FIG. 5B. At this time, since the capacitances C8 and C10 of the capacitors 17a and 17b formed between the electrodes 8 and 10 and the spherical body 1 are equal, the bridge circuit 16a is balanced and the terminal a-b.
The output Vab does not appear between the terminals. However, the electrodes 7, 9
17c, 17d formed between the spherical body 1 and the spherical body 1
Regarding the electrostatic capacitances C7 and C9 of the electrode 9, the electrode 9 is more spherical body 1.
Since the facing area of the spherical part of is small (or
Due to the large distance from the spherical body 1), the capacitance C9 becomes smaller than the capacitance C7 due to the principle of the parallel plate capacitor, the balance of the bridge circuit 16b is lost, and the c terminal-
The voltage output Vcd appears between the d terminals, and the rotation angle θX can be obtained from the value of the output Vcd.

Similarly, when the spherical actuator B rotates about the Y axis by θY, the bridge circuit 16b is balanced and the output Vcd does not appear between the c terminal and the d terminal, but the bridge circuit 16a has Since the balance is lost, the output Vab appears between the terminals a and b, and the rotation angle θY can be obtained from the value of the output Vab.

Thus, the rotation angles θX and θY of the spherical body 1
Can be obtained from the output Vcd between the c terminal and the d terminal and the output Vab between the a terminal and the b terminal.
The relationship between X and the output Vcd and the relationship between the rotation angle θY and the output Vab will be described using mathematical expressions. As shown in FIGS. 6 and 7, the resistance 1 in each bridge circuit 16a, 16b
5a, 15b, 12a, 12b; 15c, 15d, 12
The resistance values of c and 12d are RX1, RX2, RX3 and RX respectively.
4; RY1, RY2, RY3, RY4, capacitors 11a,
11b; 11c, 11d capacitance CX1, CX2; CY1,
The impedance due to CY2 is ZCX1, ZCX2; ZCY1, ZC
If Y2, the balance condition of the bridge circuit 16a is represented by RX3. (RX2 + ZCX2 + ZC10) = RX4. (RX1 + ZCX1 + ZC8) (1), and the balance condition of the bridge circuit 16b is RY3. (RY2 + ZCY2 + ZC9) = RY4. (RZ1 + ZC1). )… (2) If the voltage of the AC power supply 13 is V ₀ , the output voltage Vab between the a terminal and the b terminal of the bridge circuit 16a is expressed by the following equation (3a), and the output voltage Vab of the bridge circuit 16b is c.
The output voltage Vcd between the terminal and the d terminal is expressed by the following equation (4a).

[0028]

[Equation 1]

Here, RX3 + RX2 + ZCX2 = RX4 + RX1 + ZCX1 = Za ... (5) RX3 = RX4 = RX ... (6) RY3 + RY2 + ZCY2 = RY4 + RY1 + ZCY1 = Zb ... (7) If RY3 = RY4 = RY ... And (4a) are the following (3b)
Equation (4b) is obtained.

[0030]

[Equation 2]

Further, for simplification, if it is written that RX / Za = Ka (9) RY / Zb = Kb (10), the above formulas (3b) and (4b) are expressed by the following formulas (3c) and (3c). 4c)
It can be rewritten as an expression.

[0032]

[Equation 3]

Now, when the spherical body 1 is rotated around the X axis and the Y axis, the capacitors 17a, 17b, 17c, 1
The capacitances C7, C8, C9, C10 of 7d are roughly as shown in FIG.
If it changes as shown in (a), the respective impedances ZC7, ZC8, ZC9, and ZC10 are roughly as shown in FIG.
As shown in FIG. 8B, the outputs Vab and Vcd (effective value) change as shown in FIG. 8C. Figure 8
Impedance ZC7, ZC8, ZC9, ZC1 in (b)
Area where 0 changes (-90 ° ≤ θX, θY ≤ 90 °)
At impedances ZC7, ZC8, ZC9, ZC10
ZC8 / Za = -K1 · θX + K2 (11) ZC10 / Za = K1 · θX + K2 (12) ZC7 / Zb = -K1 · θY + K2 (13) ZC9 / Zb = K1 · θY + K2 (14) Then, the above equations (3c) and (4c) are
The following equations (3d) and (4d) are obtained.

[0034]

[Equation 4]

Here, if K1 <K2, the above (3d)
Expression, Vab = -2 {Ka · K1 · V 0 / (1 + K2) 2} · θX ... (3e) becomes, (4c) equation, Vcd = -2 {Kb · K1 · V 0 / (1 + K2) 2 } · ΘY (4e), and the relationship in FIG. 6C can be replaced with a substantially linear relationship. Therefore, the output V between the a terminal and the b terminal
It can be considered that ab is proportional to the rotation angle θX, the output Vcd between the c terminal and the d terminal can also be considered to be proportional to the rotation angle θY, and the rotation angles θX and θY can be easily detected by detecting the outputs Vab and Vcd. Can be detected.

9A and 9B are sectional views showing a spherical actuator D according to the third embodiment of the present invention. In this spherical actuator D, a magnetic flux H in the axial direction (Z-axis direction when not rotating) passing through the rotation center P of the spherical body 1 is provided in the cavity 1a of the spherical body 1 having a spherical shell shape. To attach a pair of permanent magnets 18a, 18b,
The three Hall elements 19X, 19Y, and 19Z that are integrated are arranged near the rotation center P of the spherical body 1. These Hall elements 19X, 19Y, 19Z are combined in the shape of a corner cube, and their respective detection surfaces are on the X axis,
It is arranged in a direction orthogonal to the Y axis and the Z axis, and is fixed so as to be independent of the rotation of the spherical body 1.

The spherical actuator D has an X-axis and a Y-axis.
There is a drive system that rotates around the axis, and Hall element 19
It is assumed that the magnetic flux density passing through the positions of X, 19Y and 19Z is φ ₀ . Assuming now that the spherical body 1 is rotated about the X axis by a rotation angle θX, the output ΨY of the Hall element 19Y is ΨY = κ, where the proportional constant is κ, as can be seen from the explanatory view of FIG. 10A. _{· φ 0 · cosθX ... (15} ) and the output PusaiZ of the Hall element 19Z becomes _{ΨZ = κ · φ 0 · sinθX} ... (16). The output ΨX of the Hall element 19X is the spherical body 1
Since the rotation angle θY about the Y axis is 0 and there is no interlinking magnetic flux H, ΨX = 0. Therefore, the rotation angle θX
Can be easily obtained from Eqs. (15) and (16), and θX = arctan (ΨZ / ΨY) (17) Similarly, when the spherical body 1 rotates around the Y-axis, the output ΨY of the Hall element 19Y is ΨY = 0, and the rotation angle θY is θY = arctan (ΨZ / ΨX) (18).

Further, when the spherical body 1 rotates about the X axis by θX and simultaneously rotates about the Y axis by θY, the rotation angles θX and θY can be similarly obtained. For example,
Considering a case where the vector representing the magnetic flux density φ ₀ is oriented in the direction shown in FIG. 10B with respect to the X axis, the Y axis and the Z axis, the YZ plane of the vector representing the magnetic flux density φ ₀ , ZX.
ΦZY and φX are the division vectors to the plane and the XY plane, respectively.
When Z and φXY are set, the rotation angle θX of the spherical body 1 around the X axis is equal to the angle formed by the division vector φZY and the Z axis, and Y
The rotation angle θY about the axis is equal to the angle formed by the division vector φXZ and the Z axis. Then, the values of these rotation angles θX and θY are the outputs ΨX and ΨY of the Hall elements 19X, 19Y and 19Z, respectively.
ΨZ can be used to perform calculations from the above equations (17) and (18).

FIG. 11 is a sectional view showing a spherical actuator E according to a fourth embodiment of the present invention. In this spherical actuator E, the permanent magnet 18a of the spherical actuator D shown in FIG. 9 is used. , 18b are replaced by electromagnets 20a, 20b. Also in such a spherical actuator E, the rotation direction and the rotation angles θX and θY of the spherical body 1 can be detected by the same principle as the spherical actuator D of FIG.

Moreover, in this spherical actuator E, in order to avoid the influence of magnetic noise in the surroundings (for example, due to the earth magnetism or the magnetic field generated from the electromagnetic motor), an alternating magnetic field having a constant frequency is generated by the electromagnets 20a and 20b. Then, the measurement error due to the external magnetic field can be removed by taking out only the frequency component with a bandpass filter or the like.

FIGS. 12A and 12B are a plan view and a front view showing a spherical actuator F according to the fifth embodiment of the present invention. In this spherical actuator F, the spherical body 1 is rotatably housed in a supporting member 6 having a container shape, and a portion of the spherical body 1 exposed from the supporting member 6 has a pin shape or a rod shape. The protruding portion 21 is provided so as to project. Further, above the spherical body 1, elongated holes 24a, 24b are provided.
The thin flat plate-shaped position detection plates 22a and 22b are
Are arranged so as to be orthogonal to each other, and the end portions of the position detection plates 22a and 22b have rotary shafts 25 of rotary encoders 23a and 23b installed on the upper surface of the support member 6.
It is fixed to a and 25b. Each position detection plate 22a, 2
2b can be freely rotated in a horizontal plane,
The rotary angles of the position detection plates 22a and 22b are precisely detected by the rotary encoders 23a and 23b. Also,
The long holes 24a, 24b of the position detection plates 22a, 22b have a width equal to the diameter of the protrusion 21 and have a length about the diameter of the spherical body 1, and the lengths of the position detection plates 22a, 22b are long. The projection 21 of the spherical body 1 is slidably inserted at the intersection of the holes 24a and 24b.

However, since the position of the projection 21, that is, the rotation direction and the rotation angles θX and θY of the spherical body 1 and the rotation angles of both the position detection plates 22a and 22b have a one-to-one correspondence, the rotary encoder By detecting the rotation angles of both position detection plates 22a and 22b by 23a and 23b, the rotation direction and rotation angles θX and θY of the spherical body 1 can be detected. Moreover, in this spherical actuator F, the position detection plates 22a and 22b are flat, and the rotary encoders 23a and 23 for detection are used.
Since b is attached to the upper surface of the support member 6, there is an advantage that the assemblability and maintainability are good.

FIG. 13 is a perspective view showing a spherical actuator G according to a sixth embodiment of the present invention. The spherical body driving mechanism of the spherical actuator G is published in the proceedings of the 1991 Autumn Meeting of the Japan Society for Precision Engineering,
The two drive stators 26a, 26b are brought into contact with each other from the direction orthogonal to the surface of the spherical body 1 to drive the drive stators 26a, 26
The spherical body 1 is rotated by driving b. Further, in this spherical actuator G, as shown in FIGS. 13 and 14A and 14B, rotary encoders 23a and 23b for detection are arranged concentrically with the drive stators 26a and 26b. ,
Position detection plate 22 in the shape of a thin plate having long holes 24a and 24b
a and 22b are curved along the surface of the spherical body 1 in an arc shape,
The rotary encoder 2 is provided with the end portions of the position detection plates 22a and 22b arranged so as to be orthogonal to each other along the surface of the spherical body 1.
3a, 23b fixed to the rotary shaft 25a, 25b, the long hole 2
A projecting portion 21 projecting from the spherical body 1 is inserted at the intersection of 4a and 24b.

Even in this spherical actuator G, since the position of the protrusion 21 and the rotation angle of both position detection plates 22a and 22b have a one-to-one correspondence, both position detection plates are rotated by the rotary encoders 23a and 23b. 22a, 22b
The rotation direction and the rotation angles θX and θY of the spherical body 1 can be detected by detecting the rotation angle of. Moreover, in this spherical actuator G, the position detection plates 22a and 22b are bent and the rotary encoder 23
Since the a and 23b are arranged concentrically with the stators 26a and 26b, it is possible to improve the detection accuracy of the rotation angles θX and θY, space efficiency, and assemblability. further,
The rotary shafts 25a of the rotary encoders 23a, 23b,
If 25b is arranged so as to coincide with the X axis and the Y axis, the rotation angles of the rotation shafts 25a and 25b become the rotation angles θX and θY of the spherical body 1, so that the rotary encoder 23a,
The rotation angles θX and θY can be directly detected by 23b, and there is an advantage that a calculation circuit for detection can be omitted.

[0045]

According to the first spherical actuator of the present invention, the rotation direction and the rotation angle of the spherical body can be detected by detecting the bending degrees of the two bending elements by the strain detector. Further, in the second spherical actuator of the present invention, the rotation direction and the rotation angle of the spherical body can be detected by detecting the capacitance between each electrode and the spherical body. Further, in the third spherical actuator of the present invention, the rotating direction and the rotating angle of the spherical body can be detected by detecting the magnetic flux rotating with the spherical body by the stationary magnetic flux detector. Further, in the fourth spherical actuator of the present invention, the rotation direction and the rotation angle of the spherical body are detected by detecting the rotation angle of each position detection plate that rotates with the rotation of the spherical body. You can

According to these spherical actuators, the rotational position of the spherical body can be detected with higher accuracy than before, and the spherical actuator can be controlled with high accuracy. Further, the structure of the spherical actuator capable of detecting the rotational position of the spherical body can be simplified, the structure for detecting the rotational position can be compactly housed, and a small and lightweight spherical actuator can be manufactured. Furthermore, basically, even when the spherical body is rotated at a rotation angle of 180 ° or more,
It also becomes possible to detect the rotation angle of the spherical body.

When an electromagnet is used as the magnet in the third spherical actuator, for example, an AC magnetic flux having a constant frequency is generated by the electromagnet, and only the frequency component is taken out by a bandpass filter or the like. The measurement error due to the magnetic field can be removed, and the influence of the surrounding magnetic noise (for example, due to the geomagnetism or the magnetic field generated from the electromagnetic motor) can be avoided.

Further, in the fourth spherical actuator, the position detecting plate is formed in an arc shape along the surface of the spherical body, and each angle detecting means is arranged coaxially with the driving stator,
Since each position detecting plate is rotatably supported by each position detecting means, it is possible to improve the detection accuracy of the rotation angle of the spherical body, space efficiency, and assemblability. Moreover, since the rotation angle of the angle detecting means itself becomes the rotation angle of the spherical body, there is an advantage that the rotation angle can be directly detected by the angle detecting means and the arithmetic circuit for the detection can be omitted.

[Brief description of drawings]

FIG. 1 is a sectional view showing a spherical actuator according to a first embodiment of the present invention.

2A and 2B are a perspective view and a side view showing a bending element of the above.

FIG. 3 is a diagram showing a relationship between a strain amount of a bending element and a rotation angle of a spherical body.

4 (a), (b), (c) and (d) are schematic sectional views for explaining the operation of the same.

5 (a) and 5 (b) are schematic front views showing a spherical actuator according to a second embodiment of the present invention with a part thereof omitted.

FIG. 6 is a diagram showing a spherical actuator and a measuring circuit for detecting a rotation angle of the spherical body.

FIG. 7 is a circuit diagram showing an equivalent circuit of the measurement circuit.

8 (a), (b) and (c) are explanatory views of the measurement circuit of the above.

9A is a sectional view showing a spherical actuator according to a third embodiment of the present invention, and FIG. 9B is a sectional view taken along line QQ of FIG. 9A.

10A and 10B are explanatory views showing the principle of rotation angle detection in the spherical actuator of the same.

FIG. 11 is a sectional view showing a spherical actuator according to a fourth embodiment of the present invention.

12A and 12B are a plan view and a front view showing a spherical actuator according to a fifth embodiment of the present invention.

FIG. 13 is a perspective view showing a spherical actuator according to a sixth embodiment of the present invention.

14 (a) and 14 (b) are a plan view and a front view of the same spherical actuator.

[Explanation of symbols]

1 Spherical body 2,4 Bending element 3a, 3b Strain gauge (strain detector) 7, 8, 9, 10 Electrode C measurement circuit 18a, 18b Permanent magnet 19X, 19Y, 19Z Hall element (flux detector) 20a, 20b Electromagnet 21 Protrusions 22a, 22b Position Detection Plates 23a, 23b Rotary Encoders (Angle Detection Means) 24a, 24b Long Holes 26a, 26b Drive Stator

Claims (6)

[Claims] 1. A spherical actuator in which a spherical body is rotatably supported, wherein two bending elements to which strain detectors are attached are connected so that their bending directions are orthogonal to each other, and two connected bending elements are connected. A spherical actuator characterized in that one end of the element is fixed to an inner surface of a spherical body and the other end is fixed to a stationary portion other than the spherical body. 2. A spherical actuator in which a spherical body is rotatably supported, a bottom portion of the spherical body is cut out to form a cutout portion, and electrodes are arranged in two orthogonal directions facing the bottom portion of the spherical body. Then, a spherical actuator comprising a capacitance between each of the electrodes and the spherical body. 3. A spherical actuator in which a spherical body is rotatably supported, wherein at least one magnet is attached to an inner surface of the spherical body so that magnetic flux passes through substantially the center of rotation of the spherical body, and detection surfaces are orthogonal to each other. A spherical actuator characterized in that at least two magnetic flux detectors are arranged substantially at the center of rotation of the spherical body. 4. The spherical actuator according to claim 3, wherein the magnet is an electromagnet. 5. A spherical actuator in which a spherical body is rotatably supported, wherein a projection is provided on the spherical body, and a pair of position detection plates each having a slot having a width substantially equal to the projection are provided near the spherical body. An angle detection means for detecting the rotation angle of each position detection plate is provided, and the protrusion is slidably inserted into both elongated holes at the intersection of both position detection plates. A spherical actuator characterized by. 6. The position detecting plate is formed in an arc shape along the surface of a spherical body, and a pair of the angle detecting means is arranged coaxially with a pair of drive stators for rotationally driving the spherical body. 6. The spherical actuator according to claim 5, wherein each position detecting plate is rotatably supported by each position detecting means.