JP6364155B2 - Control device and control method for vibration actuator - Google Patents

Description

  The present invention relates to a control device and a control for a vibration actuator (for example, an ultrasonic motor) that drives a moving body such as a rotor (rotor) or a slider (linear advance) using a traveling wave generated by ultrasonic vibration, for example. Regarding the method.

Conventionally, a rotary ultrasonic motor using traveling waves is known as an example of a vibration actuator.
The ultrasonic motor includes a vibrating body (stator) including a piezoelectric element and an annular elastic body to which the piezoelectric element is bonded, an annular moving body (rotor), and the moving body as the vibrating body. A pressurizing means for pressurizing contact and an electrode for applying a drive signal (high frequency voltage) to the piezoelectric element are provided.
The ultrasonic motor generates a traveling wave in the vibrating body by the expansion and contraction motion of the piezoelectric element generated by applying a driving signal to the piezoelectric element, and frictionally drives the moving body by the traveling wave.
In addition, the traveling wave is generated by synthesizing waves generated by applying two-phase driving signals having a temporal phase difference of 90 ° to the piezoelectric element.

JP 7-123752 A

  By the way, depending on the use of the above-described ultrasonic motor, for example, intermittent driving (starting / stopping) of the moving body may be continuously repeated like a wobbling operation at the time of moving image shooting in a digital camera or the like.

  In such intermittent driving of the ultrasonic motor, when the ultrasonic motor shifts from the driving state to the stopped state, the above-described two-phase driving signal is instantaneously interrupted, and the vibration of the vibrating body is settled. There is a problem that noise and vibration are generated when the ultrasonic motor is stopped because the moving body is struck against the vibrating body by the pressure applied by the pressurizing means.

  Further, when the ultrasonic motor shifts from the stopped state to the driving state, that is, at the moment when the above-described two-phase driving signal is applied at the time of starting the ultrasonic motor, it is pressed against the vibrating body by the pressing force of the pressurizing means. There was a problem that noise was generated because the moving body was floating by the traveling wave instantly.

  The present invention provides a control device and a control method for a vibration actuator that can suppress generation of noise and vibration at the time of stopping and generation of noise at the time of start-up in intermittent driving of a vibration actuator such as an ultrasonic motor. is there.

In order to achieve such an object, the first aspect of the present invention provides an annular vibrator that generates a traveling wave by applying two-phase drive signals having different phases, and an annular vibrator that is driven by the traveling wave. In a vibration actuator control device comprising a moving body, after the application of the two-phase drive signal is stopped, the application of the two-phase drive signal is resumed while the vibration of the vibration body continues. A drive signal output circuit is provided.
According to a second aspect of the present invention, in the first aspect of the present invention, the drive signal output circuit reverses the rotation direction of the movable body before and after the stop.
According to a third aspect of the present invention, there is provided a vibration actuator comprising an annular vibrating body that generates a traveling wave by applying two-phase drive signals having different phases, and an annular moving body that is driven by the traveling wave. In the control method, after the application of the two-phase drive signal is stopped, the application of the two-phase drive signal is resumed while the vibration of the vibrator continues, so that the moving body is stopped and It is characterized by starting.
The fourth of the present invention, in the third invention, characterized by reversing the direction of rotation of the moving body before and after the stop.

  According to the present invention, for example, in the intermittent drive of a vibration actuator such as an ultrasonic motor, it is possible to suppress the generation of noise and vibration at the time of stopping and the generation of noise at the time of activation.

(A) is a figure which shows the waveform etc. of the drive signal applied to a vibrating body in the control method of the ultrasonic motor which concerns on one Embodiment of this invention, (b) is the supersonic wave which concerns on another embodiment of this invention. The figure which shows the waveform etc. of the drive signal applied to a vibrating body in the control method of a sonic motor. (A) is a perspective view partially showing a configuration of an ultrasonic motor according to an embodiment of the present invention, (b) is a two-phase electrode provided on a piezoelectric body joined to a vibrating body. FIG. The block diagram which shows the structure of the drive signal output circuit of the ultrasonic motor which concerns on one Embodiment of this invention.

Hereinafter, a control device of a vibration actuator (for example, an ultrasonic motor) according to an embodiment of the present invention will be described with reference to the accompanying drawings.
As shown in FIG. 2A, the ultrasonic motor 100 of the present embodiment rotates together with the output shaft 2 that is rotatably supported, and an annular movement configured concentrically around the output shaft 2. The movable body 4 includes a body (rotor) 4 and an annular vibrating body (stator) 8 arranged on the base 6 and concentrically formed around the output shaft 2. It is maintained in a state where it is always pressed against the vibrating body 8 by the applied pressure.

  The moving body 4 includes an annular rotor ring 4a and a friction material 4b provided in an annular shape along a surface of the rotor ring 4a that faces the vibrating body 8. The rotor ring 4a is made of, for example, an aluminum alloy. On the other hand, the friction material 4b is for obtaining a stable frictional force when the moving body 4 and the vibrating body 8 are pressed against each other. For example, a synthetic resin or the like is used.

  The vibrating body 8 includes an annular stator ring 8a and an annular piezoelectric body 8b disposed on a surface of the stator ring 8a facing the base 6. In the stator ring 8a, a plurality of slits (grooves) 8g are formed at equal intervals along the circumferential direction in a portion opposite to the surface on which the piezoelectric body 8b is provided. A plurality of comb teeth 8c projecting toward the moving body 4 (specifically, the friction material 4b) are formed along the circumferential direction.

The stator ring 8a is made of, for example, a copper alloy. On the other hand, the piezoelectric body 8b (also referred to as piezoelectric ceramic) is formed of an element having a property (electrostriction) that expands and contracts when a high frequency voltage is applied thereto, and is a surface of the stator ring 8a that faces the base 6. It is joined to.
In the piezoelectric body 8b, adjacent sections are alternately polarized in the thickness direction, and electrodes 8b1 to 8b8 are provided for each section in one area of the piezoelectric body 8b, and electrodes 8b9 to 8b15 are provided in the other area. Is provided for each category.

  The spring 10 is sandwiched between the pressing member 12 fixed to the output shaft 2 and the moving body 4. In this state, the elastic force of the spring 10 is transmitted to the moving body 4, and the moving body By pressing the 4 toward the vibrating body 8, the moving body 4 (specifically, the friction material 4b) and the vibrating body 8 (specifically, each comb tooth 8c of the stator ring 8a) are always pressed. Is maintained in the state.

  Further, as shown in FIG. 2B, the electrodes 8b1 to 8b8 provided in one region of the piezoelectric body 8b include the electrode 14A of the two-phase electrodes 14A and 14B (1 in FIG. 2B). The electrode 8B9-8b15 provided in the other region of the piezoelectric body 8b is joined to the electrode 14B (FIG. 2B) of the two-phase electrodes 14A and 14B. Are joined).

  In such a configuration, when drive signals (high-frequency voltages) S1 and S2 having a temporal phase difference of 90 ° are applied to the two-phase electrodes 14A and 14B, traveling waves are generated on the top surfaces of the comb teeth 8c of the stator ring 8a. Generated. Then, the moving body 4 pressurized toward the vibrating body 8 by the spring 10 rotates around the output shaft 2 by this traveling wave.

  Next, the drive signal output circuit for the drive signals S1 and S2 applied to the electrodes 8b1 to 8b8 and the electrodes 8b9 to 8b15 via the two-phase electrodes 14A and 14B will be described.

  As shown in FIG. 3, the drive signal output circuit 200 of the present embodiment outputs a first signal (for example, a SIN wave) based on the drive command signal (ON command pulse) output from the drive trigger generation circuit 15. A first oscillation circuit 16 and a second oscillation circuit 18 that outputs a second signal (for example, a COS wave) based on the drive command signal (ON command pulse) are provided. The first oscillation circuit 16 and the second oscillation circuit 18 stop the output of the first signal and the second signal based on the stop command signal (OFF command pulse) output from the drive trigger generation circuit 15. It is configured.

  The first oscillation circuit 16 is electrically connected to the first output circuit 22 via the first burst wave generation circuit 20, and the drive signal S 1 is output from the first output circuit 22. The second oscillation circuit 18 is electrically connected to the second output circuit 28 via the phase switching circuit 24 and further via the second burst wave generation circuit 26, and the drive signal S2 is supplied to the second output circuit 28. Output from the circuit 28. The first and second burst wave generation circuits 20 and 26 have a function of setting the timing of starting and stopping the output of the drive signals S1 and S2 according to the purpose of use of the ultrasonic motor.

The first burst wave generation circuit 20 includes a counter circuit 20a, a burst time setting unit 20b, a comparison coincidence circuit 20c, a latch circuit 20d, and a switch circuit 20e.
The counter circuit 20a converts the first signal (SIN wave) output from the first oscillation circuit 16 into a rectangular pulse wave having a predetermined threshold as a maximum value, and measures the time by counting the number of pulses. Is.
The burst time setting unit 20b outputs a time width for outputting the drive signal S1 (hereinafter referred to as “S1 ON time”) and a time width for stopping the output of the drive signal S1 (hereinafter referred to as “S1 OFF time”). .) Is set.
Based on the signal output from the counter circuit 20a and the signal output from the burst time setting unit 20b, the comparison coincidence circuit 20c sends a latch ON command signal to the latch circuit 20d at the start of the ON time for outputting the drive signal S1. At the same time, a latch OFF command signal is output to the latch circuit 20d at the start of the OFF time when the output of the drive signal S1 is stopped (at the end of the ON time).
The latch circuit 20d outputs an H level signal to the switch circuit 20e based on the latch ON command signal from the comparison match circuit 20c, and switches the L level signal based on the latch OFF command signal from the comparison match circuit 20c. Output to the circuit 20e.
The switch circuit 20e turns on / off the electrical connection between the first oscillation circuit 16 and the first output circuit 22. When the output signal from the latch circuit 20d is at the L level, the switch circuit 20e is turned on ( When the output signal from the latch circuit 20d is at the H level, the OFF state (circuit open) is maintained.
Therefore, when the switch circuit 20e is in the ON state, the drive signal S1 is applied to the electrode 14A, and when it is in the OFF state, the application of the drive signal S1 is stopped. Note that when the switch circuit 20e repeats the ON state and the OFF state, the drive signal S1 applied to the electrode 14A when the switch circuit 20e is in the ON state is also referred to as a first burst wave.

The second burst wave generation circuit 26 includes a counter circuit 26a, a burst time setting unit 26b, a comparison and coincidence circuit 26c, a latch circuit 26d, and a switch circuit 26e.
The counter circuit 26a sets the second signal output from the second oscillation circuit 18 (the COS wave (or the waveform after phase shift when the phase is shifted by 180 ° in the phase switching circuit 24)) to a predetermined threshold value as the maximum value. It is converted into a rectangular pulse wave, and the time is measured by counting the number of pulses.
The burst time setting unit 26b outputs a time width for outputting the drive signal S2 (hereinafter referred to as “S2 ON time”) and a time width for stopping the output of the drive signal S2 (hereinafter referred to as “S2 OFF time”). .) Is set.
Based on the signal output from the counter circuit 26a and the signal output from the burst time setting unit 26b, the comparison coincidence circuit 26c outputs a latch ON command signal to the latch circuit 26d at the start of the ON time for outputting the drive signal S2. At the same time as outputting, a latch OFF command signal is output to the latch circuit 26d at the start of the OFF time when the output of the drive signal S2 is stopped (at the end of the ON time).
The latch circuit 26d outputs an H level signal to the switch circuit 26e based on the latch ON command signal from the comparison match circuit 26c, and switches the L level signal based on the latch OFF command signal from the comparison match circuit 26c. Output to the circuit 26e.
The switch circuit 26e turns on / off the electrical connection between the phase switching circuit 24 and the second output circuit 28. When the output signal from the latch circuit 26d is at the L level, the switch circuit 26e is in the ON state (circuit The circuit is configured to maintain the OFF state (circuit open) when the output signal from the latch circuit 26d is at the H level.
Therefore, when the switch circuit 26e is in the ON state, the drive signal S2 is applied to the electrode 14B, and when it is in the OFF state, the application of the drive signal S2 is stopped. Note that when the switch circuit 26e is repeatedly turned on and off, the drive signal S2 applied to the electrode 14B when the switch circuit 26e is turned on is also referred to as a second burst wave.

  The phase switching circuit 24 switches and outputs a positive phase (phase 0 °) output signal or a reverse phase (phase 180 °) output signal with respect to the second signal output from the second oscillation circuit 18. Yes, normal phase / reverse phase switching is performed by a command signal from a switching signal output unit (not shown) or an operation switch (not shown).

  The phase switching circuit 24 shifts the phase of the second signal from the second oscillation circuit 18 by one wavelength (= 180 °), thereby rotating the moving body 4 in the rotation directions R1 and R2 (see FIG. 2A). Are switched from forward rotation (CW) to reverse rotation (CCW), or from reverse rotation (CCW) to forward rotation (CW).

  The first output circuit 22 amplifies the first signal from the first oscillation circuit 16 input via the switch circuit 20e and applies it to the electrode 14A of the ultrasonic motor 100 as the drive signal S1. The second output circuit 28 amplifies the second signal from the phase switching circuit 24 input via the switch circuit 26e and applies it to the electrode 14B of the ultrasonic motor 100 as the drive signal S2.

Next, a control method during intermittent driving of the ultrasonic motor 100 using the drive signal output circuit 200 will be described with reference to FIG.
In the present embodiment, “starting” and “stopping” when the ultrasonic motor 100 is intermittently driven are performed by turning ON / OFF the switch circuits 20e and 26e.

  First, it is assumed that the switch circuits 20e and 26e are both ON and the phase switching circuit 24 is set to “positive phase”. In this state, when a drive command signal (ON command pulse) is output from the drive trigger generation circuit 15 to the first oscillation circuit 16 and the second oscillation circuit 18, the first signal output from the first oscillation circuit 16 is: The signal is input to the first output circuit 22 through the switch circuit 20e. The first signal is amplified by the first output circuit 22 and applied to the electrode 14A as the drive signal S1. The second signal output from the second oscillation circuit 18 is input to the second output circuit 28 via the switch circuit 26e. The second signal is amplified by the second output circuit 28 and applied to the electrode 14B as the drive signal S2.

  Thus, when the two-phase drive signals S1 and S2 having a temporal phase difference of 90 ° are applied to the electrodes 14A and 14B, a traveling wave is generated in the stator ring 8a, and the moving body 4 is rotated ( Forward rotation).

  When the preset “ON time of S1 and S2” elapses, the comparison coincidence circuits 20c and 26c output a latch ON command signal to the latch circuits 20d and 26d, whereby the latch circuits 20c and 26d H level signals are output to the circuits 20e and 26e, the switch circuits 20e and 26e are turned off (circuit open), and the application of the drive signals S1 and S2 to the electrodes 14A and 14B is stopped. For this reason, the traveling wave generated in the stator ring 8a disappears and the rotation of the moving body 4 stops.

  Next, when a preset “OFF time of S1 and S2”, for example, several μsec to several tens of μsec has elapsed, the comparison coincidence circuits 20c and 26c output a latch OFF command signal to the latch circuits 20d and 26d, As a result, the latch circuits 20c and 26d output L level signals to the switch circuits 20e and 26e, the switch circuits 20e and 26e are turned on (circuit closed), and the drive signals S1 and S2 to the electrodes 14A and 14B. Resume application. For this reason, traveling waves are generated again in the stator ring 8a, and the moving body 4 rotates.

  In the present embodiment, the “OFF time of S1 and S2” is the time during which the vibration of the stator ring 8a continues after the application of both the drive signals S1 and S2 is stopped simultaneously (for example, several μsec to several tens of μsec). Is set to In addition, the application of both the drive signals S1 and S2 is simultaneously stopped and restarted to start and stop the ultrasonic motor 100 during intermittent driving. However, the difference from the prior art is that both the drive signals S1 and S2 are applied. After the application is stopped simultaneously, the application of the drive signals S1 and S2 is resumed at the same time while the vibration of the stator ring 8a continues.

  By simultaneously stopping the application of the drive signals S1 and S2, the rotation of the moving body 4 is stopped. However, after the application of the drive signals S1 and S2 is stopped, the moving body 4 has a stator for several μsec to several tens of μsec. The vibration of the ring 8a is sustained, that is, it is in a floating state due to the remaining vibration. Since the application of the drive signals S1 and S2 is resumed at the same time while the moving body 4 is in a floating state, the moving body 4 is not knocked against the stator ring 8a by the pressure of the spring 10, and as a result, the ultrasonic wave Generation of noise and vibration when the motor 100 is stopped can be suppressed.

  In addition, since the moving body 4 is restarted while the vibration of the stator ring 8a is sustained, that is, in the floating state due to the remaining vibration, the moving body 4 does not instantaneously change from the pressure contact state to the floating state. As a result, it is possible to suppress the generation of noise during startup in the intermittent driving of the ultrasonic motor 100.

  Even if the switch circuits 20e and 26e change from the OFF state to the ON state, if the phase switching circuit 24 remains set to the “normal phase”, the rotation direction of the moving body 4 is the positive rotation before and after the stop. (CW) does not change, but if the phase switching circuit 24 is set from “normal phase” to “reverse phase” before the switch circuits 20e and 26e change from the OFF state to the ON state, the moving body The rotation direction of 4 changes from forward rotation (CW) to reverse rotation (CCW) before and after stopping. FIG. 1A shows a case where the rotation direction of the moving body 4 changes from forward rotation (CW) to reverse rotation (CCW) before and after stopping.

Hereinafter, the ultrasonic motor 100 repeats intermittent driving such as starting and stopping by alternately repeating the “OFF time of S1 and S2” and the “ON time of S1 and S2”. According to the control method, it is possible to suppress the generation of noise and vibration at the time of stopping as well as the generation of noise at the time of startup as in the prior art.
Further, in the present embodiment, the stop of the ultrasonic motor 100 stops the application of both the drive signals S1 and S2, so the application of only the drive signal S2 described later is stopped and the application of the drive signal S1 is continued. Compared with the embodiment, it is possible to reduce the amount of power to be used and to achieve an energy saving effect.

The “ON time of S1 and S2” can be arbitrarily set according to the purpose of use of the ultrasonic motor 100, etc., but the “OFF time of S1 and S2” is that the vibration of the stator ring 8a continues as described above. It is limited to a certain time (for example, several μsec to several tens μsec).
In the above-described embodiment, the application of the drive signals S1 and S2 is stopped and restarted at the same time. However, it is necessary to stop and restart the application of the drive signals S1 and S2 at the same time. There may be a slight time difference between the two.

In the above-described embodiment, when the ultrasonic motor 100 is intermittently driven, when the preset “ON time of S1 and S2” elapses, the ultrasonic motor 100 stops. You may comprise so that the ultrasonic motor 100 may be stopped based on the signal from the provided sensor.
When stopping the intermittent drive itself of the ultrasonic motor 100, a stop command signal (OFF command pulse) is output from the drive trigger generation circuit 15 to the first oscillation circuit 16 and the second oscillation circuit 18, and the first oscillation circuit 16 and This is performed by stopping the output of the first signal and the second signal output from the second oscillation circuit 18.

Next, another control method for intermittent driving of the ultrasonic motor 100 using the drive signal output circuit 200 will be described with reference to FIG.
In this embodiment, “start” and “stop” during intermittent driving of the ultrasonic motor 100 are performed by turning on and off the switch circuit 26e, and the switch circuit 20e is always in an ON state.

  First, it is assumed that the switch circuits 20e and 26e are both ON and the phase switching circuit 24 is set to “positive phase”. In this state, when a drive command signal (ON command pulse) is output from the drive trigger generation circuit 15 to the first oscillation circuit 16 and the second oscillation circuit 18, the first signal output from the first oscillation circuit 16 is: The signal is input to the first output circuit 22 through the switch circuit 20e. The first signal is amplified by the first output circuit 22 and applied to the electrode 14A as the drive signal S1. The second signal output from the second oscillation circuit 18 is input to the second output circuit 28 via the switch circuit 26e. Then, the second signal is amplified by the second output circuit 28 and applied to the electrode 14B as the drive signal S2.

  Thus, the electrodes 14A. When two-phase drive signals S1, S2 having a temporal phase difference of 90 ° are applied to 14B, a traveling wave is generated in the stator ring 8a, and the moving body 4 rotates (forward rotation) by this traveling wave.

  When the preset “ON time of S2” elapses, the comparison and coincidence circuit 26c outputs a latch ON command signal to the latch circuit 26d, whereby the latch circuit 26d outputs an H level signal to the switch circuit 26e. The switch circuit 26e is turned off (circuit open), and the application of the drive signal S2 to the electrode 14B is stopped. For this reason, the traveling wave generated in the stator ring 8a disappears and the rotation of the moving body 4 stops.

However, in the present embodiment, since the switch circuit 20e is always in the ON state, the drive signal S1 is continuously applied to the electrode 14A, and the traveling wave generated in the stator ring 8a disappears. However, since the standing wave by the drive signal S1 is generated in the stator ring 8a, the vibration of the stator ring 8a continues.
Therefore, although the rotation of the moving body 4 stops, the moving body 4 is in a floating state due to the vibration of the stator ring 8a due to the standing wave, and therefore the moving body 4 is struck against the stator ring 8a by the pressing force of the spring 10. As a result, the generation of noise and vibration when the ultrasonic motor 100 is stopped can be suppressed.

  Next, when the preset “S2 OFF time” elapses, the comparison and coincidence circuit 26c outputs a latch OFF command signal to the latch circuit 26d, whereby the latch circuit 26d outputs the L level to the switch circuit 26e. The switch circuit 26e is turned on, and the application of the drive signal S2 to the electrode 14B is resumed. For this reason, a traveling wave is generated again in the stator ring 8a, and the movable body 4 that has been stopped rotates.

In the present embodiment, since the switch circuit 20e is always in the ON state, the drive signal S1 is continuously applied to the electrode 14A, and only the switch circuit 26e is turned on at the time of starting in the intermittent drive. Then, the application of only the drive signal S2 to the electrode 14B is resumed.
For this reason, even if the rotation of the moving body 4 stops, the stator ring 8a still has a standing wave due to the drive signal S1, so that the vibration of the stator ring 8a continues and the moving body 4 is in a floating state. The stator ring 8a is not pressed by the pressing force of the spring 10.
Therefore, even if the application of the drive signal S2 to the electrode 14B is resumed, the moving body 4 does not instantaneously change from the pressure contact state to the floating state, and as a result, at the time of startup in the intermittent drive of the ultrasonic motor 100. Generation of noise can be suppressed.
Further, at the time of start-up in intermittent driving, only the switch circuit 26e is turned on and only the drive signal S2 is applied to the electrode 14B. Therefore, when the two-phase drive signals S1 and S2 are simultaneously applied to the piezoelectric body 8b. Generation of noise generated from the piezoelectric body 8b can be prevented.

  Even if the switch circuit 26e changes from the OFF state to the ON state, as long as the phase switching circuit 24 remains set to the “normal phase”, the rotational direction of the moving body 4 is the forward rotation (CW) before and after the stop. However, if the phase switching circuit 24 is set from “normal phase” to “reverse phase” before the switch circuit 26e changes from the OFF state to the ON state, the rotational direction of the moving body 4 is not changed. Will change from forward rotation (CW) to reverse rotation (CCW) before and after stopping. FIG. 1B shows a case where the rotational direction of the moving body 4 changes from forward rotation (CW) to reverse rotation (CCW) before and after stopping.

Hereinafter, the “S2 OFF time” and the “S2 ON time” are alternately repeated, whereby the ultrasonic motor 100 repeats intermittent driving such as starting and stopping. However, according to the control method of the present embodiment. Thus, it is possible to suppress the generation of noise and vibration during stoppage and the generation of noise during start-up as in the prior art.
The “S2 ON time” and the “S2 OFF time” can be arbitrarily set according to the purpose of use of the ultrasonic motor 100 or the like.

In the above-described embodiment, when the preset “S2 ON time” elapses during the intermittent drive of the ultrasonic motor 100, the ultrasonic motor 100 stops and the preset “S2 OFF time”. However, the ultrasonic motor 100 may be stopped and started based on a signal from a separately provided sensor.
When stopping the intermittent drive itself of the ultrasonic motor 100, a stop command signal (OFF command pulse) is output from the drive trigger generation circuit 15 to the first oscillation circuit 16 and the second oscillation circuit 18, and the first oscillation circuit 16 and This is performed by stopping the output of the first signal and the second signal output from the second oscillation circuit 18.

  In the above-described two embodiments, the drive signals S1 and S2 are both examples using full-wave SIN waves (COS waves). However, in the drive signal output circuit 200, for example, the switch circuit 20e. , 26e may be provided with a half-wave rectifier circuit so that, for example, a full wave is applied during forward rotation (CW) and a half wave is applied during reverse rotation (CCW). Moreover, you may make it apply a half wave at any time of forward rotation (CW) and reverse rotation (CCW). In this way, if a half-wave drive signal is used, an energy saving effect can be achieved by reducing the amount of power used, compared to the case where a full-wave drive signal is used, and forward rotation (CW) and reverse rotation ( In any case of CCW), if a half-wave drive signal is used, a further energy saving effect can be achieved.

  In the above-described two embodiments, the control device and the control method of the rotary ultrasonic motor 100 are both exemplified. However, the control device and the control method of the present invention can be applied to a direct acting ultrasonic motor. The present invention can be applied, and is not limited to an ultrasonic actuator using vibration in the ultrasonic band, and can be applied to those using vibrations other than the ultrasonic band.

2 Output shaft 4 Moving body 4a Rotor ring 4b Friction material 6 Base 8 Vibrating body 8a Stator ring 8b Piezoelectric body (piezoelectric ceramics)
10 Spring 14A, 14B Electrode 100 Ultrasonic motor 200 Drive signal output circuit S1 Drive signal (SIN wave signal)
S2 Drive signal (COS wave signal)

Claims (4)

In a control device for a vibration actuator comprising an annular vibrating body that generates traveling waves by applying two-phase driving signals having different phases, and an annular moving body that is driven by the traveling waves,
A vibration comprising a drive signal output circuit that resumes the application of the two-phase drive signal while the vibration of the vibrating body continues after the application of the two-phase drive signal is stopped. Actuator control device.   2. The vibration actuator control device according to claim 1, wherein the drive signal output circuit reverses the rotation direction of the movable body before and after the stop. 3. In a control method of a vibration actuator comprising an annular vibrating body that generates traveling waves by applying two-phase driving signals having different phases, and an annular moving body that is driven by the traveling waves,
After stopping the application of the two-phase drive signal, the application of the two-phase drive signal is resumed while the vibration of the vibrator continues, thereby stopping and starting the moving body. A control method of a vibration actuator characterized by the above. Control how the vibration actuator according to claim 3, characterized in that reversing the rotational direction of the moving body before and after the stop.

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