JPH10122809A - Spherical actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect the rotary angle of a spherical body accurately by a compact and simple configuration by arranging an electrode plate for constituting a capacitance in a space that is formed at an area to an electrode part while the capacitance opposes the electrode part provided on the surface of the spherical body. SOLUTION: A spherical body 10 that is supported so that it can rotate freely is formed nearly spherically of insulation material such as ceramic and a shaft part 11 is connected to an upper surface. A nearly square electrode film 12 is applied to the lower surface of the spherical body 10 and electrode plates 13-16 that are divided into four portions are arranged at the lower part of the electrode film 12. The electrode plates 13-16 form a concentric spherical shape with the spherical part of the spherical body 10 and the gap between the electrode plates 13-16, and the spherical body 10 is constant, thus a capacitance is constituted between the electrode film 12 and the electrode plates 13-16. A capacitance detection circuit detects the capacitance between the electrode film 12 and the electrode plates 13-16, and each output CA, CB, CC, CD, and G are supplied to an operation circuit, thus the rotary angle of the spherical body 10 is calculated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a spherical actuator having a function of detecting a rotation angle of a spherical body.

[0002]

2. Description of the Related Art In recent years, in the field of optical communications and semiconductors, a micromanipulator is required to assemble fine optical components and semiconductors with high accuracy. Therefore, in a spherical actuator which is applied to a micromanipulator and rotatably supports a spherical body, 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.

A method of detecting a rotation angle in a conventional spherical actuator is disclosed in Japanese Patent Application Laid-Open No. H06-210585. This is because two bending elements with a strain detector attached to a spherical actuator are connected so as to be orthogonal to each other in the bending direction, and when the spherical body rotates, one of the two bending elements according to the rotation direction and the rotation angle of the spherical body. Alternatively, both are bent, and the amount of bending is detected by a strain detector, thereby detecting the rotation direction and rotation angle of the spherical body. In addition, a notch is provided at the bottom of the spherical body, and an electrode facing the notch is arranged, and by detecting a capacitance formed between the spherical body and the electrode, the rotation of the spherical body is performed. This is a method of detecting a direction and a rotation angle.

[0004]

However, in the conventional method as described above, in order to detect the deformation of the bending element by the strain gauge, one end of two orthogonal bending elements is fixedly connected to the support member. ing. Therefore, the torque generated by the actuator is reduced. Also,
The characteristics of the actuator tend to change depending on the strain gauge temperature drift and how to attach it, making it difficult to detect with high accuracy.
Further, the detection method using capacitance proposed in the publication has a problem that the detection accuracy is not good because the output of the sensor is non-linear. SUMMARY OF THE INVENTION An object of the present invention is to provide a spherical actuator capable of detecting the rotation angle of a spherical body with high accuracy with a small size, light weight, and simple configuration.

[0005]

Means for Solving the Problems In order to solve the above problems and achieve the object, a spherical actuator of the present invention is constituted as follows. (1) A spherical actuator according to the present invention is a spherical actuator in which a spherical body made of an insulator is rotatably supported, and an electrode unit provided on a surface of the spherical body;
An electrode plate provided so as to face the electrode portion and arranged to constitute a capacitance in a space formed by the electrode portion;
It is composed of (2) The spherical actuator according to the present invention is the actuator according to the above (1), wherein the electrode portion is provided on a bottom surface of the spherical body and curved so as to form a concentric spherical shape with the spherical portion of the spherical body. The two sets of the formed electrode plates were opposed to the electrode portions, and were arranged so as to be orthogonal to each other. (3) The spherical actuator according to the present invention is the actuator according to the above (1), wherein two electrode portions are provided on the side surface of the spherical body so as to be orthogonal to each other, and have a spherical shape concentric with the spherical portion of the spherical body. A pair of the electrode plates bent so as to be formed are arranged along the rotation direction of the spherical body so as to face each of the electrode portions one by one.

[0006] As a result of taking the above measures, the following operations occur. (1) According to the spherical actuator of the present invention, since the electrode plate is arranged so as to form an electrostatic capacity in a space formed between the electrode unit and the electrode unit provided on the surface of the spherical body and the electrode unit. When the spherical body rotates, the capacitance between the electrode portion provided on the spherical body and the electrode plate changes, and by detecting this capacitance, the rotation direction and the rotation angle of the spherical body are changed. Can be detected.

As described above, since the deformation of the bending element by the strain gauge is not detected unlike the prior art, and the output of the sensor does not become non-linear when detecting the capacitance, high accuracy and stability are achieved. By detecting the rotation direction and rotation angle of the spherical body, the spherical actuator can be controlled with high accuracy. In addition, since it is structurally simple, the configuration can be made compact, and a small and lightweight spherical actuator can be manufactured. this is,
This is particularly effective for positioning control of the microactuator. (2) According to the spherical actuator of the present invention, two sets of the electrode plates are provided such that the electrode portion is provided on the bottom surface of the spherical body and is curved so as to be concentric with the spherical portion of the spherical body. Are arranged so as to be opposed to the electrode portion and orthogonal to each other, so that the spherical actuator can be configured more easily. (3) According to the spherical actuator of the present invention, two electrode portions are provided on the side surface of the spherical body so as to be orthogonal to each other,
Since a pair of the electrode plates curved so as to form a concentric spherical shape with the spherical portion of the spherical body are arranged along the rotational direction of the spherical body so as to face each of the electrode portions, one set of the spherical body is formed. Is exposed without being covered by the electrode portion or the electrode plate, the spherical actuator can be effectively used as a spherical actuator that often supports the spherical body from the bottom.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) FIG. 1 is a view showing a main part of a spherical actuator according to a first embodiment of the present invention.
(A) is a top view, (b) is a side view, and (c) is a bottom view.

In the spherical actuator shown in FIG. 1, a spherical body 10 is rotatably supported by a suitable support member (not shown). The spherical body 10 is formed in a substantially spherical shape by using an insulating material such as ceramics, and a shaft portion 11 for attaching an output unit such as an arm is connected to an upper surface thereof.

On the lower surface of the spherical body 10, an electrode film 12 is applied, and the shape of the electrode film 12 is substantially square. Below the electrode film 12, electrode plates 13, 14, 1 and 4 divided into four so as to enclose the lower hemisphere of the spherical body 10.
5 and 16 are arranged. Thereby, a capacitance is formed between the electrode film 12 and each of the electrode plates 13, 14, 15, 16. The space between each of the electrode plates 13, 14, 15, 16 and the spherical body 10 is insulated by an air gap or an insulating film.

The electrode plates 13, 14, 15, and 16 are curved so as to form a concentric spherical surface with the spherical portion of the spherical body 10, and are located between the electrode plates 13, 14, 15, 16 and the spherical body 10. The gap is constant. Also, the electrode plate 13,
14, 15, and 16 are arranged such that the intervals between adjacent ones are equal.

FIG. 2 is a block diagram showing the configuration of the angle detection and measurement circuit of the spherical actuator shown in FIG. In this angle detection measurement circuit, the capacitance detection circuit 30,
Each of 31, 32, and 33 is connected to the arithmetic circuit. The capacitance detection circuits 30, 31, 32, and 33 detect and output the capacitance between the electrode film 12 and each of the electrode plates 13, 14, 15, and 16, respectively.

The capacitance detecting circuits 30, 31, 32, 33
1 are connected to CA, CB, CC, CD, and G shown in FIG. 1C, respectively. Then, the capacitance detection circuits 30, 31, 32,
Each output SCA, SCB, SCC, SCD from 33 is
It is supplied to the arithmetic circuit 34. Then, the arithmetic circuit 34 performs the operations shown in the following equations (1) and (2), and calculates the θ of the spherical body 10.
The rotation angle φx in the X direction and the rotation angle φy in the θY direction are calculated.

Φx = k {(SCA + SCB) − (SCC + SCD)} (1) φy = k {(SCA + SCD) − (SCB + SCC)} (2) Next, the principle of detecting the rotation angle of the spherical body 10, that is, The process of deriving equations (1) and (2) will be described. First, it is assumed that the spherical body 10 has been rotated by φx in the θX direction from a state (initial state) in which the areas where the electrode film 12 and the electrode plates 13, 14, 15, 16 overlap each other have the same area (initial state).
At this time, assuming that the radius of the spherical body 10 is a, the length of one side of the electrode film 12 is L, and the distance between the respective electrode plates can be ignored, the electrode film 12 and the respective electrode plates 13, 14, 15, 16 Each area SA, SB, SC, SD of the part where
Is represented by the following equations (3) and (4).

SA = SB = L / 2 (L / 2 + a · φx) (3) SC = SD = L / 2 (L / 2−a · φx) (4) The capacitance is the area of the electrode. Therefore, the capacitances SCA, SCB, SCC, and SCD between the electrode film 12 and each of the electrode plates 13, 14, 15, and 16 are proportional to k.
If it is set to 1, it is represented by the following equations (5) to (8).

SCA = k1 × SA = k1 · L / 2 (L / 2 + a · φx) (5) SCB = k1 × SB = k1 · L / 2 (L / 2 + a · φx) (6) SCC = k1 × SC = k1 · L / 2 (L / 2−a · φx) (7) SCD = k1 × SD = k1 · L / 2 (L / 2−a · φx) (8) 9) is derived.

(SCA + SCB) − (SCC + SCD) = k1 · 2 · a · L · φx (9) Expression (9) indicates that the rotation angle φx can be obtained by expression (1).

Similarly, in the θY direction, the rotation angle φy can be calculated by equation (2). As can be seen from these equations (1) and (2), the arithmetic circuit 34
Is proportional to the rotation angle. Therefore, according to the spherical actuator of the first embodiment, the rotation angle and the rotation direction of the spherical body can be detected with high accuracy.

(Second Embodiment) FIGS. 3A and 3B are diagrams showing a main part of a spherical actuator according to a second embodiment of the present invention, wherein FIG. 3A is a top view and FIG. 3B is a side view. , (C)
Is a bottom view. In the spherical actuator shown in FIG.
The spherical body 10 is rotatably supported by a suitable support member (not shown). The spherical body 10 is formed in a substantially spherical shape by using an insulating material such as ceramics, and a shaft portion 11 for attaching an output unit such as an arm is connected to an upper surface thereof.

An electrode film 12 is applied to the lower surface of the spherical body 10, and the shape of the electrode film 12 is substantially square. Below the electrode film 12, two sets of electrode plates 21, 22 and 23, 24 are arranged so as to be orthogonal to each other along the lower hemisphere of the spherical body 10. Thereby, a capacitance is formed between the electrode film 12 and each of the electrode plates 21, 22, 23, 24. Then, each of the electrode plates 21, 22, 2
The space formed between the spherical bodies 3 and 24 and the spherical body 10 is insulated by an air gap or an insulating film.

The electrode plates 21, 22, 23, and 24 are curved so as to form a concentric spherical surface with the spherical portion of the spherical body 10, and are located between the electrode plates 21, 22, 23, and 24 and the spherical body 10. The gap is constant. Also, the electrode plate 13,
14, 15, and 16 are arranged such that the intervals between adjacent ones are equal.

FIG. 4 is a block diagram showing the configuration of the angle detection and measurement circuit of the spherical actuator shown in FIG. In this angle detection measurement circuit, the capacitance detection circuit 30,
Each of 31, 32, and 33 is connected to the arithmetic circuit. The capacitance detection circuits 30, 31, 32, and 33 detect and output the capacitance between the electrode film 12 and each of the electrode plates 21, 22, 23, and 24, respectively.

Capacitance detection circuits 30, 31, 32, 33
Output signals CX1, CX2, CY1, CY2, and G are respectively CX1, CX2, CY1, and C shown in FIG.
It leads to Y2 and G. Then, the capacitance detection circuit 3
Each output SCX1, SCX from 0, 31, 32, 33
2, SCY1 and SCY2 are supplied to the arithmetic circuit 44.
The arithmetic circuit 44 calculates the following equations (3) and (4) to calculate the rotation angle φx in the θX direction and the rotation angle φy in the θY direction of the spherical body 10.

Φx = k (SCX1-SCX2) (3) φy = k (SCY1-SCY2) (4) These expressions (3) and (4) are the same as those described in the first embodiment. Can be guided in the process. Therefore, according to the spherical actuator of the second embodiment, the rotation angle and the rotation direction of the spherical body can be detected with high accuracy.

(Third Embodiment) FIGS. 5A and 5B are views showing a main part of a spherical actuator according to a third embodiment of the present invention, wherein FIG. 5A is a top view and FIG. 5B is a front view. , (C)
Is a side view. In the spherical actuator shown in FIG.
The spherical body 10 is rotatably supported by a suitable support member (not shown). The spherical body 10 is formed in a substantially spherical shape by using an insulating material such as ceramics, and a shaft portion 11 for attaching an output unit such as an arm is connected to an upper surface thereof.

An electrode film 51 and an electrode film 52 are respectively applied to side surfaces in two directions orthogonal to each other. These electrode films 51 and 52 are respectively formed in the θX direction and the θY direction.
Two pairs of electrode plates 53, 54 and 5 which are circular in shape for independently detecting the angle of direction and are curved so as to be concentric with the spherical portion of the spherical body 10.
5 and 56 pass through the centers of the electrode films 51 and 52, respectively.
It is arranged along the X direction and the θY direction so that the gap with the spherical body 10 is constant. The electrode plate 5
3, 55 are arranged along the upper hemisphere of the spherical body 10, and the electrode plates 54, 56 are arranged along the lower hemisphere of the spherical body 10.

Thus, the electrode film 51 and each electrode plate 53,
, And between the electrode film 52 and the electrode plates 55 and 56. Then, each electrode plate 53, 54, 55, 56 and the spherical body 10 (electrode film 5
1, 52) are insulated by an air gap or an insulating film. The operation principle of the spherical actuator of the third embodiment is the same as that of the second embodiment, and the capacitance detection circuit shown in FIG. 4 is used.

According to the third embodiment, the spherical body 10
Is different from the structures shown in the conventional example and the first and second embodiments in that the bottom of the first embodiment can be exposed without being covered by the electrode film or the electrode plate. Therefore, the micro-manipulator can be effectively used as a spherical actuator that often supports the spherical body from the bottom, and the piezoelectric body contacts the bottom of the spherical body 10 in the spherical actuator. As described above, also in the spherical actuator according to the third embodiment, the rotation angle and the rotation direction of the spherical body can be detected with high accuracy. The present invention is not limited to only the above embodiments, and can be implemented with appropriate modifications without departing from the scope of the invention.

[0029]

According to the present invention, it is possible to provide a spherical actuator capable of detecting the rotation angle of a spherical body with high accuracy with a small, lightweight and simple configuration.

[Brief description of the drawings]

FIG. 1 is a diagram showing a main part of a spherical actuator according to a first embodiment of the present invention, where (a) is a top view,
(B) is a side view, (c) is a bottom view.

FIG. 2 is a block diagram showing a configuration of an angle detection and measurement circuit of the spherical actuator according to the first embodiment of the present invention.

FIG. 3 is a diagram showing a main part of a spherical actuator according to a second embodiment of the present invention, where (a) is a top view,
(B) is a side view, (c) is a bottom view.

FIG. 4 is a block diagram showing a configuration of an angle detection and measurement circuit of a spherical actuator according to second and third embodiments of the present invention.

FIG. 5 is a diagram showing a main part of a spherical actuator according to a third embodiment of the present invention, where (a) is a top view,
(B) is a front view, (c) is a side view.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Spherical body 11 ... Shaft part 12 ... Electrode film 13-16 ... Electrode plate 21-24 ... Electrode plate 30-33 ... Capacitance detection circuit 34 ... Operation circuit 44 ... Operation circuit 51 ... Electrode film 52 ... Electrode film 53 ~ 56 ... electrode plate

Claims (3)

[Claims] A spherical actuator rotatably supporting a spherical body formed of an insulator, comprising: an electrode portion provided on a surface of the spherical body; and an electrode provided to face the electrode portion; And an electrode plate disposed so as to form a capacitance in a space defined by the part. 2. The method according to claim 1, wherein the electrode portion is provided on a bottom surface of the spherical body, and two sets of the electrode plates curved so as to form a concentric spherical shape with the spherical portion of the spherical body face the electrode portion. ,
2. The device according to claim 1, wherein the components are arranged to be orthogonal to each other.
3. The spherical actuator according to item 1. 3. A pair of said electrode plates which are provided on the side surface of said spherical body so as to be orthogonal to each other and which are curved so as to form a concentric spherical shape with a spherical portion of said spherical body. The spherical actuator according to claim 1, wherein the spherical actuator is arranged along a rotation direction of the spherical body so as to face the electrode unit.