JPH05123992A - Surface wave manipulator - Google Patents

Abstract

PURPOSE:To provide a surface wave manipulator capable of moving a joint part smoothly with simple structure while being compact and lightweight. CONSTITUTION:An exterior case 5 is formed into spherical shell shape so as to form a spherical cavity 8 inside. Two stators 6, 7 formed of surface wave vibrators are attached to the inner surface of the cavity 8 in such a way that the advance directions of the surface waves are mutually othogonal. A spherical rotor 4 is enclosed in the exterior case 5, and the stators 6, 7 are brought into pressure contact with the surface of the rotor 4. When the stators 6, 7 are driven, the rotor 4 is rotated by the surface waves.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface wave manipulator. Specifically, the present invention relates to a universal joint type surface wave manipulator that moves a rotor in two axial directions by utilizing surface wave type ultrasonic vibrations.

[0002]

2. Description of the Related Art In a multi-joint type manipulator which has been conventionally applied to a robot or the like, an arm or the like can be freely moved in two axial directions by combining two uniaxial type rotating shafts which rotate in one axial direction. I am able to rotate to.

However, in the manipulator of such a form, when a rotary motor is used as an actuator for driving each rotary shaft, the manipulator has two driving parts, so that the driving mechanism becomes complicated and the driving parts are complicated. There was a drawback that the weight of the

Further, FIGS. 10A and 10B show another conventional example, which is a joint actuator 51 having three degrees of freedom.
(Journal of the Japan Society of Mechanical Engineers, July 1991 issue). In this actuator 51, a spherical body 53 provided at the lower end of a triangular prism-shaped arm 52 is inserted into an outer cylinder 55 of a base 54, and a receiving seat 56 slidably accommodated in the outer cylinder 55. By urging the spring upward by the spring 57,
The spherical body 5 is provided between the receiving seat 56 and the flange 55a of the outer cylinder 55.
3 is pivotally supported. Further, the outer peripheral surface of the arm 52 is provided with upper and lower drive parts 58, and each drive part 58 is asymmetric with respect to the axis of the arm 52 as shown in FIG. 10B. Three piezoelectric elements 59 are attached, and a weight 60 of the same weight is fixed to the tip of each piezoelectric element 59 attached in a cantilever manner so as to project from the arm 52.

Therefore, one or a plurality of piezoelectric elements 5
The weight 60 can be shockedly moved by extending or compressing 9, and the repulsive force can move the arm 52 in three directions. For example, six piezoelectric elements 59
When they are simultaneously extended by the same amount, the repulsive force causes the arm 52 to rotate about its axis. In addition, the piezoelectric elements 59 are unbalancedly expanded and contracted to move the arms 5.
The axial direction of 2 can be changed to 2 directions, and as a result, the arm 52 can have three degrees of freedom in the driving direction.

However, in such an actuator, it is necessary to attach a plurality of piezoelectric elements and weights to the arm, so that a lightweight actuator cannot be obtained. Also, if the arm is continuously moved in a certain direction, for example, a certain piezoelectric element is suddenly expanded to move the arm, and then the piezoelectric element is contracted slowly so as not to move the arm, and then the piezoelectric element is rapidly moved again. It was necessary to extend the arm and move the arm repeatedly, and the arm could not be moved smoothly.

FIG. 11 is a perspective view of another conventional example, which is an actuator for a robot using an ultrasonic motor (Proceedings of the 1991 Spring Meeting of the Precision Engineering Society of Japan, Spring Conference, P.207-208). ). In this actuator, two stators 63 and 64 are in contact with the outer peripheral surface of a spherical rotor 61 having an arm 62. The stators 63 and 64 use a rotary ultrasonic motor, and are in contact with the rotor 61 in the X-axis direction and the Y-axis direction which are orthogonal to each other, and are in contact with the rotor 61 from the X-axis direction. When the stator 63 is driven, the rotor 61 rotates around the X axis, and the rotor 6 rotates in the Y axis direction.
When the stator 64 that is in contact with 1 is driven, the rotor 61
Rotates around the Y axis. Therefore, both stators 6
By rotating the rotor 61 with 3, 64, the arm 62 can be rotated in any direction.

However, in this actuator, since the stators 63 and 64 are rotary ultrasonic motors, they must be arranged in two directions orthogonal to each other, and the stators of the other partner interfere with each other, and There is a drawback that the rotation angle of 61 is limited. For example, in FIG.
2, the stator 62 is driven to move the arm 62.
When trying to rotate from the Z-axis direction around the X-axis, 9
When the rotation angle θ is smaller than 0 degrees, the arm 62 moves to the stator 64.
However, there is a drawback that the rotation range of the arm 62 is limited.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the drawbacks of the above-mentioned conventional examples, and an object thereof is to continuously move a movable part such as a rotor or an arm over a wide rotation range. The object is to provide a surface wave manipulator that can be moved to any position, has a simple structure, and is lightweight.

[0010]

In a surface wave manipulator of the present invention, a spherical rotor is rotatably supported, and a pair of stators each composed of a linear surface wave oscillator is used for traveling direction of each surface wave. Are in contact with the surface of the rotor so that they are different from each other.

Further, a groove may be formed on the surface of the stator along the contact surface with the rotor.

[0012]

In the present invention, the rotor can be rotated by moving the surface of the rotor by the stator that is in contact with the rotor. Moreover, since one set of stators is composed of two linear type surface acoustic wave oscillators having different traveling wave directions, it is possible to obtain two degrees of freedom at one joint portion and rotate the rotor in any direction. be able to.

Moreover, by using the stator composed of the surface wave oscillator, the structure can be simplified and the manipulator can be reduced in size and weight. Further, since the rotor can be rotated at a low speed, a speed reduction mechanism is not required, and the static torque is large, so a brake is not required.

Further, the rotor can be continuously and smoothly moved over a wide rotation range.

Further, since electromagnetic waves are not generated, the peripheral equipment is not disturbed.

[0016]

1 is a sectional view of a surface wave manipulator A according to an embodiment of the present invention. The manipulator A has a joint type structure and is configured by combining a joint portion 2 provided at one end of an arm 1 and a rotor 4 provided at one end of an arm 3.

The joint portion 2 is provided with two stators 6 and 7 formed of a linear type surface wave oscillator on the inner surface of a spherical shell-shaped exterior case 5 fixed to the arm 1. A spherical cavity 8 is formed in the outer shell-shaped outer case 5,
Two stators 6 and 7 are arranged in a cross shape on the inner wall surface of the cavity 8 such that the directions of the traveling waves are orthogonal to each other. Further, a circular hole-shaped opening 9 is formed in a part of the outer case 5 so as to face the intersecting position of the two stators 6 and 7.
This opening area is smaller than 1/2 of the total surface area of the outer case 5.

The rotor 4 has a spherical shape and is housed in the cavity 8 of the outer case 5. In order to store the rotor 4 in the outer case 5, it is preferable that the outer case 5 be divided into two parts. The surfaces of the stators 6 and 7 are in pressure contact with the spherical surface of the rotor 4 housed in the outer case 5, and the rotor 4 is held so that it can rotate without rattling. Moreover, a part of the rotor 4 is exposed from the opening 9 of the outer case 5, the diameter of the opening 9 is considerably larger than the diameter of the arm 3, and the rotor 4 rotates within the fixed range within the joint 2. You can do it.

The stators 6 and 7 composed of linear type surface wave oscillators drive the rotor 4 by the same principle as that used as an ultrasonic motor, and an elastic body is obtained by vibrating a piezoelectric element. It generates surface wave vibrations such as flexural vibrations and stretching vibrations on the surface. FIG. 4 is a diagram for explaining the operation of the stators 6 and 7, and shows a linear type surface wave oscillator B. This linear type surface acoustic wave oscillator B is one in which a piezoelectric element 10 such as PZT is attached to the back surface of an elastic body 11.
For example, the polarization direction (the polarization direction is indicated by an arrow in FIG. 4) is inverted at regular intervals. Then, when the piezoelectric element 10 is driven in a predetermined drive mode, particles on the surface of the elastic body 11 follow an elliptical orbit due to a traveling wave (deflection traveling wave) traveling in the W direction in the elastic body 11 as shown in FIG. The rotor (or slider) 4a is moved in the V direction by drawing and moving.

Therefore, the linear type surface wave oscillator B as shown in FIG. 4 is bent into an arc shape to form an arc-shaped stator 6 or 7, and the stator 6 or 7 is driven by contacting this with the outer peripheral surface of the rotor 4. For example, as shown in FIG. 5, the rotor 4 can be rotated around a rotation axis Z that is perpendicular to the circumferential direction in which the stator 6 or 7 extends. In addition, slit-shaped grooves are cut into the elastic portions of the stators 6 and 7 at regular intervals.

Therefore, as in the embodiment of the present invention (FIG. 1), if the two stators 6 and 7 are in contact with the surface of the rotor 4 so as to be orthogonal to each other, the orthogonal two directions θx and θy.
The rotor 4 can be rotated, and the arm 3 can be moved in any direction by any angle. Moreover, since the surface wave manipulator A only needs to be provided with the two stators 6 and 7 on the inner surface of the outer case 5, the size and weight can be reduced and the surface wave manipulator A can be continuously and smoothly rotated in any direction. it can. Further, it can be driven at a low speed and a high torque can be obtained.

Further, in the surface wave manipulator having the structure as in the present invention, the two stators 6 and 7 can be integrated in one place by intersecting each other, and
Since the lengths of the stators 6 and 7 can be shortened, the pivot range of the rotor 4 can be widened by pivotally supporting the rotor 4 by an appropriate pivoting means. For example, if the stators 6 and 7 are shortened as shown in FIG. 6, the rotation angles θx and θy of the rotor 4 until the arm 3 collides with the stators 6 and 7 can be increased to 90 degrees or more. By shortening 7, the rotation range of the rotor 4 can be further widened.

FIG. 3 is a front view seen from the arm 3 side of the rotor 4. A pattern as shown in FIG. 3 is drawn on at least the hemisphere on the arm 3 side of the rotor 4. That is,
A radial pattern 12 is drawn on one half and a concentric pattern 13 is drawn on the other half.
Then, the rotor 4 exposed from the opening 9 of the joint 2
By reading the patterns 12 and 13 drawn on the surface of the disk with an encoder (not shown), for example, the rotation angle or azimuth of the rotor 4 or the joint portion 2 in the biaxial directions can be detected. Alternatively, the patterns 12 and 13 may be read from a window (not shown) opened in the outer case 5. In addition, this pattern 12,
13 may be a printed one or a marking line engraved on the rotor 4.

In the above embodiment, the stators 6, 7 are attached to the inner wall surface of the cavity 8 of the outer case 5, but the stators 6, 7 may be embedded in the inner wall surface of the cavity 8 of the outer case 5. good. By embedding the stators 6, 7 in the inner wall surface of the cavity 8 so that the surface of the stator 6, 7 and the inner wall surface of the cavity 8 are substantially flush with each other, the rotor 4, the stator 6, 7, and the outer case 5 are Since the contact area of the rotor increases, the rotor 4 can be supported more stably.

FIG. 7A shows different shapes of the stators 6 and 7. The stator 6 shown in FIG. 2 or FIG.
7 is a quadric surface (spherical surface) whose inner surface has almost the same curvature as the rotor 4.
However, the stators 6 and 7 in FIG.
It is curved only in the direction and is in line contact with the rotor 4 as shown in FIG. That is, the stators 6 and 7 have a curved line 14
It comes into contact with the rotor 4 along the
It has a straight surface in the direction perpendicular to 4. With such a shape, the stators 6 and 7 can be easily manufactured.

Further, FIG. 8 (a) shows a V-shaped groove 15 formed along the contact direction on the surfaces of the stators 6, 7 which are curved only in one direction. In the stators 6 and 7, the rotor 4 is fitted in the groove 15 as shown in FIG. 8B, so that the rotor 4 is stable. Furthermore, since the stators 6 and 7 make line contact with the rotor 4 along the two curved lines 16, the contact area between the rotor 4 and the stators 6 and 7 increases, and the driving force of the rotor 4 increases.

FIG. 9 is a front view showing a surface wave manipulator C according to another embodiment of the present invention. In this embodiment, bearings 17 and 17 such as ball bearings and roller bearings which are arranged so as to face each stator 6 and 7.
Are brought into contact with the rotor 4, and the rotor 4 is rotatably supported by the stators 6, 7 and the bearings 17, 17. Therefore, in this embodiment, an external case that easily limits the rotation angle of the rotor 4 is not necessary (a frame-like one that supports the stators 6, 7 and the bearing 17) is required, and the length of the stator 4 is also increased. The length can be shortened, and the rotation range of the rotor 4 (range in which the arm 3 moves) can be widened. Further, the rotor 4 has a mark 19 for detecting a reference point (origin), and the stator 6 is provided on the outer peripheral surface of the rotor 4.
Two non-contact encoders 18 for detecting the rotation angle of the rotor 4 in the rotation direction by 7 are installed. Then, the direction of the arm 3 is detected by the encoder 18. The bearing 17 may also function as the non-contact encoder 18.

The names of the stators 6 and 7 and the rotor 4 do not specify how they are used, but merely indicate those that are fixed with respect to the outer case 5 and those that rotate. Therefore, in use, the rotor 4 side may be stationary and the joints 2 side may be moved by driving the stators 6 and 7.

[0029]

According to the present invention, two joints are provided at one joint.
It is possible to manufacture a small and lightweight manipulator that can obtain the degree of freedom. Also, you can move the rotor at low speed,
Since the torque is large, a speed reduction mechanism and a brake are unnecessary. Furthermore, there is an advantage that the rotor can be continuously and smoothly moved, and no electromagnetic is generated so that peripheral devices are not disturbed.

[Brief description of drawings]

FIG. 1 is a sectional view showing a surface wave manipulator according to an embodiment of the present invention.

2A and 2B are a cross-sectional view and a front view of a joint portion including a stator.

FIG. 3 is a front view showing the above rotor.

FIG. 4 is a schematic perspective view for explaining a driving principle by surface wave vibration used in the present invention.

FIG. 5 is an explanatory diagram for explaining the principle for rotating the rotor by the surface wave vibration of the stator.

FIG. 6 is a side view for explaining a rotation angle of the surface wave manipulator according to the present invention.

7A and 7B are a perspective view showing a stator having another structure and a cross-sectional view showing a contact state between the stator and the rotor.

8A and 8B are a perspective view showing a stator having another structure and a sectional view showing a contact state between the stator and the rotor.

FIG. 9 is a front view showing a surface wave manipulator according to still another embodiment of the present invention.

10A and 10B are a partially cutaway front view and a plan view of an arm of a conventional example.

FIG. 11 is a perspective view showing another conventional example.

FIG. 12 is a front view for explaining the above problem.

[Explanation of symbols]

 2 joint part 4 rotor 6,7 stator

Claims (2)

[Claims] 1. A spherical rotor is rotatably supported, and a pair of stators composed of linear surface wave oscillators are brought into contact with the surface of the rotor so that the traveling directions of the surface waves are different from each other. Surface wave manipulator characterized by. 2. The surface wave manipulator according to claim 1, wherein a concave groove is formed on the surface of the stator along the contact surface with the rotor.