JP2004229455A - Oscillatory actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an oscillatory actuator, with improved high-speed performance which can be positioned with accuracy, even in jogging. <P>SOLUTION: The oscillatory actuator uses ultrasonic motors designed so that oscillating bodies are caused to produce ultrasonic vibration and movable bodies are relatively moved via frictional members by the ultrasonic vibration. In the actuator, the ultrasonic motors are disposed in a plurality of stages via the movable bodies, and the actuator is provided with a controller which controls the driving of the ultrasonic motors. The ultrasonic motors are individually controlled by the controller. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an improvement of a vibration actuator that moves a movable body using an ultrasonic motor.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, as a vibration actuator of this type, for example, it is disclosed in Patent Document 1 or the like. In this vibration actuator, as shown in FIG. 6, a linear scale 52 is placed on a base board 51, and a measuring head 53 is provided at a position facing the linear scale 52 to constitute a position detecting means 54. Further, the pressing member 57 of the ultrasonic motor 56 is brought into contact with the driving force transmitting member 55 perpendicularly to the longitudinal direction, and the position information from the position detecting means 54 accompanying the movement of the stage 58 is preset. Based on the deviation from the reference position information of the stage 58, the control unit 59 performs, for example, PID calculation processing, and performs feedback control for outputting a command signal to the ultrasonic motor 56 to the driver 60, thereby obtaining ultrasonic waves. The pressing member 57 of the motor 56 performs an elliptical motion, and the stage 58 is moved along the guide member 61 by friction driving between the pressing member 57 and the driving force transmitting member 55.
[0003]
In other words, the above-mentioned conventional vibration actuator uses one ultrasonic motor 56 to reciprocate the stage 58 as a movable body by itself.
[0004]
[Patent Document 1]
JP-A-2002-27768 [0005]
[Problems to be solved by the invention]
Meanwhile, the moving speed of the ultrasonic motor 1 is generally lower than that of a motor used for positioning an object such as the stage 58 described above. Therefore, when the object is finely moved, positioning can be performed with high accuracy. However, when the object moves at a high speed, for example, 280 mm / sec, the positioning accuracy is deteriorated as compared with a normal positioning motor. was there.
[0006]
Therefore, it has been proposed to improve the driving force by arranging a plurality of ultrasonic motors 1 side by side and improve the positioning accuracy during high-speed movement. However, even in this case, the speed is lower than the moving speed of the positioning motor using the magnetic force, and the high-speed performance of the vibration actuator is insufficient.
[0007]
SUMMARY OF THE INVENTION It is an object of the present invention to provide a vibration actuator capable of improving the high-speed performance of an ultrasonic motor and positioning with high accuracy even during fine movement.
[0008]
[Means for Solving the Problems]
The object of the present invention is to provide a vibration actuator using an ultrasonic motor that generates ultrasonic vibrations on a vibrating body and relatively moves a moving body through a friction member by the ultrasonic vibrations. This is achieved by arranging the ultrasonic motors in a plurality of stages and providing a control device for controlling the drive of the ultrasonic motor, and controlling the ultrasonic motors individually by the control device. You.
[0009]
Further, the above object is effectively achieved by arranging one or more ultrasonic motors in parallel at each stage of the ultrasonic motor arranged over the plurality of stages.
[0010]
Further, the above object is effectively achieved by causing the control device to drive all the ultrasonic motors when the moving body moves at a high speed.
[0011]
Further, the above object is achieved more effectively by causing the control device to drive only the ultrasonic motor arranged at the position closest to the moving body at the time of fine movement.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0013]
FIG. 1 shows a vibration actuator according to a first embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a first ultrasonic motor provided on a fixing member 2 such as a base board. , An elliptical motion is generated in the vibrating body 3. Due to the elliptical motion of the vibrating body 3, the friction member 4 moves in the direction of the arrow in FIG.
[0014]
The friction member 4 is provided with a first guide member 5 extending in the direction of the arrow in FIG. 1. A first movable member 6 as a movable member is mounted on the first guide member 5 so as to be reciprocally movable. I have. The first moving body 6 moves integrally with the friction member 4 at the speed V in the direction of the arrow in FIG. 1 based on the elliptical motion of the vibrating body 3.
[0015]
Further, a first position sensor 20 for detecting a position is attached to the first moving body 6, and the position of the first moving body 6 on the first guide component 5 is detected by the first position sensor 20. It is supposed to. Thereby, the first ultrasonic motor 1 and the first moving body 6 constitute the first-stage vibration actuator A via the friction member 4.
[0016]
Further, a second ultrasonic motor 7 is fixed to the first moving body 6, and the second ultrasonic motor 7 moves integrally with the first moving body 6. By driving the second ultrasonic motor 7, an elliptical motion is generated in the vibrating body 8, and the friction member 9 is moved in the direction of the arrow in FIG.
[0017]
Further, a second guide component 10 extending in the direction of the arrow in FIG. 1 is provided on the friction member 9, and a second moving body 11 is mounted on the second guide component 10 so as to be reciprocally movable. The second moving body 11 moves integrally with the friction member 9 at a speed V with respect to the first moving body 6 in the direction of the arrow in FIG. 1 based on the elliptical motion of the vibrating body 8.
[0018]
Further, a second position sensor 21 for detecting a position is attached to the second moving body 11, and the position of the second moving body 11 on the second guide component 10 is detected by the second position sensor 21. It is supposed to. Thus, the second ultrasonic motor 7 and the second moving body 11 constitute the second-stage vibration actuator B via the friction member 9.
[0019]
Further, a third ultrasonic motor 12 is fixed to the second moving body 11, and the third ultrasonic motor 12 moves integrally with the second moving body 11. By driving the third ultrasonic motor 12, an elliptical motion is generated in the vibrating body 13 to move the friction member 14 in the direction of the arrow in FIG.
[0020]
The friction member 14 is provided with a movable body 15 extending in the direction of the arrow in FIG. The moving body 15 moves at a speed V with respect to the second moving body 11 in the direction of the arrow in FIG. 1 based on the elliptical motion of the vibrating body 13 integrally with the friction member 14.
[0021]
Furthermore, a third position sensor 22 and an absolute position sensor 23 for detecting a position are attached to the moving body 15, and the second guide component of the moving body 15 is detected by the third position sensor 22 and the absolute position sensor 23. 10 and an absolute position with respect to the fixed member 2 are detected. Thereby, the third ultrasonic motor 12 and the moving body 15 constitute the third-stage vibration actuator C via the friction member 14.
[0022]
Then, the control device 30 that controls the movement of the moving body 15 receives the position detection signals from the first, second, and third position sensors 20, 21, 22, and the absolute position sensor 23, as shown in FIG. , A switching signal is output to the first, second, and third changeover switches 16, 17, and 18 to control the driving of the first, second, and third ultrasonic motors 1, 7, and 12. . Further, a command signal generator 31 is connected to the control device 30 so that a command signal from the command signal generator 31 to the moving body 15 is transmitted.
[0023]
Thereby, the control device 30 switches the operation of the first, second, and third changeover switches 16, 17, and 18 based on the command signal from the command signal generator 31. For example, when moving the moving body 15 at a high speed, the first, second, and third changeover switches 16, 17, and 18 are all turned on, and the first, second, and third position sensors 20, 21, 22, and absolute Based on the position signal from the position sensor 23, the driving of the first, second, and third ultrasonic motors 1, 7, and 12 can be controlled to move the moving body 15 at high speed. For example, assuming that the abilities of the first, second, and third ultrasonic motors 1, 7, and 12 are the same, the moving bodies 6, 11, and 15 move at a relative speed V with respect to the ultrasonic motors 1, 7, and 12, respectively. Then, the first moving body 6 moves at a speed V with respect to the fixed member 2, the second moving body 11 moves at a speed 2V with respect to the fixed member 2, and the moving body 15 moves with respect to the fixed member 2. And moves at a speed of 3V. That is, when a three-stage vibration actuator is used, three times the moving speed can be obtained as compared with a one-stage vibration actuator.
[0024]
When performing positioning at the time of fine movement, as shown in FIG. 3, the control device 30 turns on only the third changeover switch 18 and turns off the other first and second changeover switches 16 and 17. Then, only the third ultrasonic motor 12 of the third-stage vibration actuator C is driven. Therefore, the moving body 15 can be moved with high accuracy.
[0025]
Note that the capabilities of the first, second, and third ultrasonic motors 1, 7, 12 may be appropriately changed according to the purpose of movement and the application.
[0026]
Therefore, in the first embodiment, by controlling the changeover switches 16, 17, and 18 under the control of the control device 30, the speed of the moving body 15 is appropriately changed according to the moving purpose and use of the moving body 15. be able to. That is, by performing ON-OFF control of the changeover switches 16, 17, and 18, the three ultrasonic motors can be driven by combination control, and the moving speed of the moving body 15 can be optimally controlled. As a result, for example, when high-speed movement is required, all the ultrasonic motors 1, 7, 12 are driven by the control of the changeover switches 16, 17, 18; , 12, only the third ultrasonic motor 12 closest to the moving body 15 is driven. Thereby, the individual control of the ultrasonic motors 1, 7, 12 becomes possible according to the moving purpose and application, and the moving speed of the moving body 15 can be appropriately changed. Therefore, the high-speed performance of the vibration actuator is improved, and positioning can be performed with high accuracy even during fine movement.
[0027]
By the way, in the first embodiment, when only the first ultrasonic motor 1 farthest from the moving body 15 is driven at the time of the fine movement, the mass of the whole apparatus necessary for the movement becomes large, and the response at the time of positioning is poor. Become. Therefore, the control device 30 drives only the third ultrasonic motor 12 arranged at the position closest to the moving body 15.
[0028]
FIG. 4 shows a second embodiment of the vibration actuator according to the present invention. The same members as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. In the first embodiment, the three-stage vibration actuators A, B, and C are used to move the moving body 15, but in the second embodiment, two ultrasonic motors 1, 7 are provided in each stage. , 12 are provided, and the moving body 15 is moved in the direction of the arrow. As a result, the driving force required to move the moving bodies 6, 11, 15 in each stage increases. That is, the driving force required for moving the moving body 15 is increased, so that the moving body 15 can be moved at a high speed. For example, when the two ultrasonic motors 1, 7, and 12 arranged in parallel have the same performance, about twice the driving force can be obtained in each stage.
[0029]
FIG. 5 shows a third embodiment of the vibration actuator according to the present invention. The same members as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. In the above-described second embodiment, two ultrasonic motors 1, 7, and 12 are provided in each stage. In the third embodiment, the number of ultrasonic motors installed in each stage is determined according to the purpose of movement and use. It can be changed as appropriate to improve the degree of freedom of positioning and the like.
[0030]
That is, in FIG. 5, the first-stage vibration actuator A is provided with six ultrasonic motors 1 and moves the two first moving bodies 6 via the friction members 4 by driving the ultrasonic motors 1. The second-stage vibration actuator B includes four ultrasonic motors 7 and moves the two second moving bodies 11 via the friction members 4 by driving the ultrasonic motors 7. In the third-stage vibration actuator C, two ultrasonic motors 12 are arranged, and the moving body 15 is moved by driving the ultrasonic motors 12.
[0031]
Accordingly, the driving force required for moving the moving body 15 increases, and the high-speed performance of the vibration actuator improves. Also, by controlling the ultrasonic motors 1, 7, 12 by ON / OFF-controlling the changeover switches 16, 17, 18, high-precision positioning can be performed even during fine movement.
[0032]
In the above embodiments, one or two moving bodies 6 and 11 are arranged. However, the present invention is not limited to this, and three or more moving bodies may be arranged. Further, the number of ultrasonic motors is not limited to the number in each of the above embodiments, but can be changed as appropriate according to the purpose of movement and the application.
[0033]
In addition, as the vibration actuator used in the present invention, any type can be used as long as it utilizes a resonance phenomenon of the actuator using a piezoelectric element.
[0034]
In the above embodiments, the absolute position sensor 23 is provided only on the moving body 15 of the third-stage actuator C. However, the absolute position sensors are provided on the moving bodies 6 and 11 of the first and second-stage actuators A and B. Alternatively, the relative position or the absolute position may be detected for each moving object.
[0035]
Further, in each of the above embodiments, the mechanical switches as shown in FIGS. 2 and 3 are used as the changeover switches 16, 17, and 18. However, an electronic switch such as a semiconductor switch may be used. From the viewpoint of switching stability, an electronic switch is actually used more often.
[0036]
【The invention's effect】
As described above, according to the vibration actuator of the present invention, another ultrasonic motor is attached to a moving body that is moved by an ultrasonic motor, and a plurality of ultrasonic motors are arranged in a plurality of stages via the moving body. Since each ultrasonic motor is independently driven and controlled, the moving body can be moved at a high speed. That is, when two ultrasonic motors having the same capacity are combined in two stages, almost twice the moving speed is obtained, and when three ultrasonic motors are combined in three stages, almost three times the moving speed is obtained. Further, at the time of fine movement requiring fine positioning, the moving body is moved only by the ultrasonic motor arranged at the position closest to the moving body, and accurate positioning is possible. Therefore, the high-speed performance of the ultrasonic motor is improved, and positioning can be performed with high accuracy even during fine movement.
[Brief description of the drawings]
FIG. 1 is an explanatory view showing a first embodiment of a vibration actuator according to the present invention, showing a state in which one ultrasonic motor is arranged in each stage.
FIG. 2 is a diagram illustrating a configuration for controlling a plurality of ultrasonic motors at the time of high-speed operation during coarse movement.
FIG. 3 is a diagram illustrating a configuration for controlling a plurality of ultrasonic motors during fine movement.
FIG. 4 is an explanatory view showing a second embodiment of the vibration actuator of the present invention, showing a state in which two ultrasonic motors are arranged on each stage.
FIG. 5 is an explanatory view showing a third embodiment of the vibration actuator of the present invention, showing a state where the number of ultrasonic motors arranged in each stage is made variable.
FIG. 6 is a diagram showing a schematic configuration of a conventional vibration actuator.
[Explanation of symbols]
A First-stage vibration actuator B Second-stage vibration actuator C Third-stage vibration actuator 1 First ultrasonic motor 2 Fixed member 3 Vibration member 4 Friction member 5 First guide component 6 First moving body 7 Second ultrasonic motor 8 Vibrating body 9 Friction member 10 Second guide component 11 Second moving body 12 Second ultrasonic motor 13 Vibrating body 14 Friction member 15 Moving body 16 First changeover switch 17 Second changeover switch 18 Third changeover switch 20 First position sensor 21 second position sensor 22 third position sensor 23 absolute position sensor 30 controller 31 command signal generator

Claims (4)

A vibration actuator using an ultrasonic motor that generates ultrasonic vibration in a vibrating body and relatively moves a moving body through a friction member by the ultrasonic vibration,
The ultrasonic motor is arranged in a plurality of stages via the moving body, and a control device for controlling the driving of the ultrasonic motor is provided, and the ultrasonic motor is individually controlled by the control device. A vibration actuator, characterized in that: 2. The vibration actuator according to claim 1, wherein one or a plurality of ultrasonic motors are arranged in parallel at each stage of the ultrasonic motor arranged over the plurality of stages. 3. The vibration actuator according to claim 1, wherein the control device drives all the ultrasonic motors when the moving body moves at a high speed. 4. The vibration actuator according to claim 1, wherein the control device drives only an ultrasonic motor arranged at a position closest to the moving body at the time of fine movement.

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