JPH10151415A - Driving apparatus and driving method for ultrasonic actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To carry out smooth and highly precise ultrasonic actuator operation with a simple structure even in the case the driving force is increased by arranging a plurality of ultrasonic actuators in the same direction. SOLUTION: A plurality of ultrasonic actuators 1-a, 1-b are arranged in the same direction. Electricity application controlling apparatuses 6-a to apply high frequency voltage to the ultrasonic actuators 1-a, 1-b are installed. The electricity application controlling apparatuses 6-a separately send out resonant frequency signals or non-resonant signals and control driving and non-driving of an object body 2 to be driven by the ultrasonic actuators 1-a, 1-b, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving apparatus and a driving method of an ultrasonic actuator for driving a driven body by generating ultrasonic vibration by an electro-mechanical energy conversion element such as a piezoelectric element or an electrostrictive element.

[0002]

2. Description of the Related Art FIG. 4 shows an example of one conventional ultrasonic actuator disclosed in Japanese Patent Application No. 7-39609. In a conventional ultrasonic actuator, a substantially rectangular parallelepiped resonator 11 made of brass and having a pair of electromechanical transducers 12 arranged on one surface is formed in such a shape that resonance vibration and resonance bending vibration are simultaneously excited. . A stainless steel pin 13 hardened into a node of the vibration of the resonator 11 is press-fitted. A protrusion 14 for fixing the electromechanical transducer 12 at the center of the upper surface of the resonator 11 has a surface perpendicular to the main body of the resonator 11 and is integrally formed. The other end surface of the electromechanical transducer 12 is firmly fixed to the resonator 11 by a fixing member 15 and a screw 16 so that the end face of the electromechanical transducer 12 is pressed and stopped by the projection 14. When the electromechanical transducer 12 is fixed, an adhesive is applied to the entire surface of the electromechanical transducer 12 which is in contact with the resonator 11, and the electromechanical transducer 12 and the resonator 1
The fixation of 1 is strengthened. Here, the electrodes to the electromechanical transducer 12 are A, GND and B, GND. For example, the electrodes to the electromechanical transducer 12 on the left side are A, GND, and are called A phase. The electrode is B,
It will be referred to as GND and B phase. At the bending vibration antinode position on the opposite side of the surface on which the electromechanical transducer 12 is arranged,
A pair of sliding projections 17 are provided.

FIGS. 5 and 6 show examples in which two ultrasonic actuators are arranged in the same direction to form an ultrasonic actuator. The pin 13 of the resonator 11 is sandwiched in a V groove 19 of a hardened stainless steel holder 18, and a pressing spring 21 is provided on a vertical axis 20 of the V groove 19 of the holder 18 on the upper surface of the holder 18. The opposite side (the upper part in the figure) of the pressing spring 21 is in contact with a pressing screw 23 screwed to the housing 22, and the pressing screw 23 is rotated through the holder 18 via the holder 18. The pressing force is applied to the resonator 11.

The side surface of the holder 18 is
Are supported by bearing means 24 so that they can move in the vertical axis 20 direction without resistance. The sliding projection 1
A sliding member 25 is bonded and fixed to a driven body 26 on a surface with which the base 7 contacts, and the driven body 26 is held by a bearing means 28 on a base 27 so as to be movable in the X direction, and one As shown in FIG. 6, a pair of ultrasonic actuators are arranged symmetrically with respect to the same driven body 26 as viewed in the moving direction of the driven body 26.

[0005] The operating principle of the conventional ultrasonic actuator is such that primary longitudinal vibration (X-direction vibration: see FIG. 7) and secondary bending vibration (Y-direction vibration: see FIG. 8) of the resonator 11 of the ultrasonic actuator. Resonator 1 so that the resonance frequency of
1 is determined, and elliptical vibration is generated by supplying electric power having a 90 ° phase shift to the A phase and the B phase of the two electromechanical transducers 12 at that frequency to generate the elliptical vibration and press the driven body 26 against this. Thereby, the driven body 26 is driven.

The two electromechanical transducers 12 of the one ultrasonic actuator are applied with a voltage having a phase difference of 90 ° from a high-frequency power source (not shown) and a resonance frequency of the resonator 11, so that the abdomen of the resonator 11 is applied. The sliding projection 17 adhered and fixed to each other performs an elliptical vibration, and the bearing means 28
The upper driven body 26 is driven in the X direction. Similarly, the other ultrasonic actuator is similarly driven at the same drive frequency.

[0007]

The thrust due to ultrasonic elliptical vibration in one ultrasonic actuator described above is:
It is uniquely determined by the characteristic value of this one ultrasonic actuator, and no further thrust can be obtained. Therefore, when a large thrust is required, such as when driving a heavy driven body, a plurality of ultrasonic actuators are arranged in the same direction, and a thrust added by the number of arranged ultrasonic actuators is generated.

However, if the same power is supplied to all the ultrasonic actuators arranged in the same direction at the same timing, a large thrust can be obtained, but the resolution of the thrust also increases, and the thrust cannot be changed smoothly. , Precise positioning of the driven body
There is a disadvantage that smooth and high-precision control such as suppression of vibration cannot be performed. Further, when a drive device is connected to each of a plurality of ultrasonic actuators arranged in the same direction to form a system, there is a disadvantage that the device is complicated, large and expensive.

An object of the present invention is to solve the above-mentioned drawbacks of the prior art and to realize a smooth and highly accurate drive with a simple structure even if a plurality of ultrasonic actuators are arranged in the same direction to increase the thrust. And a driving method for the ultrasonic actuator.

[0010]

Means for Solving the Problems In order to achieve the above object, the present invention has the following constitution. The invention according to claim 1 includes a substantially rectangular parallelepiped resonator, and two electromechanical transducers fixed to the resonator, and applying high-frequency voltages having different phases to the two electromechanical transducers. By generating a standing wave elliptical vibration in the resonator by the standing wave elliptical vibration, in the ultrasonic actuator driving device to drive an ultrasonic actuator that drives a driven body pressed against the resonator, A plurality of the ultrasonic actuators are provided, and an application controller for controlling driving of the plurality of ultrasonic actuators is provided.

According to a second aspect of the present invention, in the configuration of the first aspect, the number of the application controllers is a divisor of the number of the ultrasonic actuators.

According to a third aspect of the present invention, in the configuration of the first aspect, the ratio of the thrusts for driving the driven body of the ultrasonic actuator is a power of two, and the number of the application controllers is ultrasonic. The number was the same as the number of actuators.

According to a fourth aspect of the present invention, there is provided a resonator having a substantially rectangular parallelepiped shape,
Having two electromechanical transducers fixed to the resonator, and applying a high-frequency voltage having a different phase to each of the two electromechanical transducers to generate standing wave elliptical vibration in the resonator. A driving method for driving an ultrasonic actuator that drives a driven body pressed against the resonator by the standing wave elliptical vibration, wherein a plurality of the ultrasonic actuators are arranged in the same direction; The driving of the ultrasonic actuator at the position is controlled by the application controller.

According to a fifth aspect of the present invention, in the configuration of the fourth aspect, the plurality of ultrasonic actuators form a plurality of groups, and power is supplied to the same group of the ultrasonic actuators at the same timing. The number of the groups was a divisor of the number of the ultrasonic actuators.

According to a sixth aspect of the present invention, in the configuration of the fourth aspect, the ratio of the thrusts for driving the driven body of the ultrasonic actuator is a power of two, and the ultrasonic wave is driven in accordance with a necessary thrust. Control is performed by combining driving and non-driving of the actuator.

FIG. 1 is a diagram showing an example of the configuration of the present invention. In FIG. 1, 1 is an ultrasonic actuator,
Reference numeral 2 denotes a driven body. The ultrasonic actuator 1 includes a resonator 11 and an electromechanical transducer 1 as described in the related art.
2, one driven body 2 is driven by the N ultrasonic actuators 1 and the like. Driven body 2
A sliding projection 17 fixed to the resonator 11 of the ultrasonic actuator 1 is pressed. Reference numeral 3 denotes a resonance frequency signal generation unit that generates a signal having a resonance frequency at which the resonator 11 causes primary longitudinal vibration and secondary bending vibration. Reference numeral 4 denotes a direction phase shifter, which shifts the phase by + 90 ° or −90 ° in accordance with the direction in which the driven body 2 is moved with respect to the input. Reference numeral 5 denotes a power amplifier, which amplifies each signal generated by the application controller 6 and the directional phase shifter 4 to power to be supplied to the ultrasonic actuator 1. Reference numeral 6 denotes an application controller, which receives a resonance frequency signal output from the resonance frequency signal generator 3 and outputs the resonance frequency signal as it is, or outputs a non-resonance signal in which the resonator 11 does not resonate. .
Here, the non-resonant signal means that even if the non-resonant signal is applied to the electromechanical transducer 12 of the ultrasonic actuator 1 via the power amplifying unit 5 or the like, the resonator 11 generates both primary longitudinal vibration and secondary bending vibration. A signal that does not occur, such as a constant DC signal or a signal at a frequency away from the resonance frequency. In addition,
Assuming that the number of ultrasonic actuators 1 is N and the number of ultrasonic actuator groups to which the same power is supplied at the same timing is m, the configuration in the case of N = 6 and m = 2 is illustrated here. The number is not limited. Group G ₁ is composed of three ultrasonic actuator 1-a,
Application controller for controlling the signal to be applied to the ultrasonic actuator 1-a is a 6-a, the group G ₂ is composed of three ultrasonic actuator 1-b, to be applied to the ultrasonic actuator 1-b The application controller for controlling the signal is 6
-B.

Next, the operation of the present invention will be described. In the present invention configured as described above, the driving device of the ultrasonic actuator operates as follows. First, the resonator 11
Output from the resonance frequency signal generator 3 a signal having a resonance frequency fr that can excite the primary longitudinal vibration and the secondary bending vibration.
The output signal from the resonance frequency signal generator 3 is applied to the application controller 6
-A, 6-b, and outputs either the resonance frequency signal as it is or the non-resonance signal in which the resonator 11 does not resonate.

When stopping the driven body 2, both the application controllers 6-a and 6-b output non-resonant signals. This non-resonant signal is input to the direction phase shifter 4, but is applied to the application controller 6.
-A and 6-b are output as non-resonant signals similar to the outputs. The outputs of the application controllers 6-a and 6-b and the output of the direction phase shifter 4 are power-amplified by the power amplifier 5 and applied to the ultrasonic actuator 1. However, since a non-resonant signal is applied, the primary longitudinal vibration and the secondary bending vibration cannot be excited in the resonator 11 and do not resonate. Therefore, the sliding projection 17 does not perform the operation of pushing the driven body 2,
The driven body 2 stops.

When the driven body 2 is moved at high speed, both the application controllers 6-a and 6-b directly output the resonance frequency signal. This resonance frequency signal is input to the directional phase shifter 4, and is set to + 90 ° or −9 depending on the moving direction of the driven body 2.
It is output as a signal shifted in phase by 0 °. The outputs of the application controllers 6-a and 6-b and the output of the direction phase shifter 4 are respectively input to the power amplifier 5, and amplify each signal up to the power to be supplied to the ultrasonic actuator 1. Each of the amplified power signals is supplied to the A-phase or B-phase electromechanical transducer 12 of the ultrasonic actuator 1. In the ultrasonic actuator 1 to which the power is supplied, the primary longitudinal vibration and the secondary bending vibration are excited by the resonator 11, and the sliding protrusion 1
7 generates a standing wave elliptical vibration. Therefore, in all six ultrasonic actuators 1-a and 1-b, the sliding protrusion 17 pushes the driven body 2 and drives the driven body 2.

When the driven body 2 is moved smoothly and with high precision, one of the application controllers 6-a and 6-b outputs the resonance frequency signal as it is, and the other outputs the non-resonance signal. . Here, a case where the application controller 6-a outputs the resonance frequency signal as it is and the application controller 6-b outputs the non-resonance signal will be described. The resonance frequency signal 6-a1 output from the application controller 6-a is divided into a signal 6-a2 input directly to the power amplifier 5 and a signal 6-a3 input to the direction phase shifter 4. The signal 6-a3 is + 90 ° according to the direction in which the driven body 2 is moved by the direction phase shifter 4.
Alternatively, it is output as a signal 6-a4 shifted in phase by -90 degrees. The signal 6-a2 and the signal 6-a4 are input to the power amplifier 5, and are amplified to the power to be supplied to the ultrasonic actuator 1-a. Each of the amplified power signals is supplied to the A-phase or B-phase electromechanical transducer 12 of the ultrasonic actuator 1. In the ultrasonic actuator 1-a to which the power is supplied, the primary longitudinal vibration and the secondary bending vibration are excited in the resonator 11, and the standing wave elliptical vibration is generated. Therefore, in the ultrasonic actuator 1-a,
The sliding protrusion 17 pushes the driven body 2 to drive the driven body 2. On the other hand, the non-resonant signal 6-b1, which is the output of the application controller 6-b, is the signal 6-b directly input to the power amplifier 5.
2 and a signal 6-b3 input to the direction phase shifter 4. The signal 6-b3 is input to the direction phase shifter 4, and is output as a non-resonant signal 6-b4 similar to the output of the application controller 6-b. The signal 6-b2 and the signal 6-b4 are power-amplified by the power amplifying unit 5 and applied to the ultrasonic actuator 1-b. However, since a non-resonant signal is applied, the primary longitudinal vibration and the secondary bending vibration cannot be excited in the resonator 11 and do not resonate. Therefore, the sliding projection 17 does not perform the operation of pushing the driven body 2.

Thus, the ultrasonic actuator 1-a
Drives the driven body 2, but the ultrasonic actuator 1-b
Does not drive the driven body 2, so that compared to the case where the same power is supplied to the ultrasonic actuator 1-a and the ultrasonic actuator 1-b at the same timing, the driven body 2
Can be generated more smoothly and with high precision. That is, the ultrasonic actuators 1-a,
When the driven body 2 is driven by 1-b, first, the driven body 2 is driven by the ultrasonic actuator 1-a, and then the electric power is supplied to the ultrasonic actuator 1-b, and the driven body already driven is driven. By applying a thrust to 2, a smooth and highly accurate drive can be obtained. In addition, by stopping the driving of the driven body 2 in a stepwise manner, the driven body 2 is less affected by inertia and the like, and smooth high-precision driving can be obtained.

Further, according to the present configuration example, compared to the case where the ultrasonic actuator 1 drives the driven body 2 by one,
Times can drive the driven member 2 in the thrust, since signals of the same power in each of the same timings in the group G ₁ in the group G ₂ is applied, application control unit 6 need not be six prepared Only two components are required, and the driving device can be simplified. In this configuration example, the group G ₁ of the ultrasonic actuator 1-a
3, an ultrasonic actuator 1-b group G ₂ is illustrated the case of three parallel connected, in this case the number of the ultrasonic actuator 1 group G ₁ and the group G ₂ are the same but in parallel connection , The ultrasonic actuators 1 may be connected in series within the same group.

[0023]

[First Embodiment of the Invention] The first embodiment of the present invention will be described with reference to FIG. FIG. 2 is a block diagram showing the overall configuration in the first embodiment. In FIG.
The ultrasonic actuator, driven body, resonance frequency signal generator, directional phase shifter, and power amplifier that perform the same functions as in FIG. Omitted.

The switch 8 is a component of the application controller 7 and outputs one of the output of the resonance frequency signal generator 3 and the ground level. The number of ultrasonic actuators 1 is five, and the number of ultrasonic actuator groups to which the same power is supplied at the same timing is also five.
Group ultrasonic actuator 1 g ₁ is 1-a, the switch that controls a signal to be applied to the ultrasonic actuator 1-a is 8-a, the group g ₂ of the ultrasonic actuator 1-b, the ultrasonic actuator 1- switch for controlling the signal to be applied to b 8-b, the ultrasonic actuator 1-c group g _3, the ultrasonic actuator 1-c
The switch 8-c to control the signal to be applied to, the group g ₄ ultrasonic actuator 1-d, the switch that controls a signal to be applied to the ultrasonic actuator 1-d is 8-d, the group g ₅ The ultrasonic actuator is 1-
e, a switch for controlling a signal to be applied to the ultrasonic actuator 1-e is 8-e.

Next, a description will be given of a method of driving the ultrasonic actuator by the driving device having the above configuration. When the resonance frequency signal is output from the resonance frequency signal generation unit 3, the resonance frequency signal is output to the switches 8-a, 8-b, 8-c, 8-
d, 8-e, and the switches 8-a to 8-e output the resonance frequency signal as it is or output a ground level signal. Even if the signal of the ground level is amplified by the power amplifier 5, the level is not limited as long as the resonator 11 does not resonate. Hereinafter, the ground level signal is referred to as 0V.

Switches 8-a, 8-b, 8-c, 8-
When all of d and 8-e output 0V, these signals are input to the direction phase shifter 4, and the switches 8-a, 8-b,
0V similar to the outputs of 8-c, 8-d and 8-e is output from the direction phase shifter 4. These switches 8-a, 8-
The outputs of b, 8-c, 8-d, 8-e and the output of the directional phase shifter 4 are power-amplified by the power amplifier 5 and applied to the ultrasonic actuator 1. However, since 0 V is a signal of a level at which the resonator 11 does not resonate even if it is amplified, even if it is applied to the ultrasonic actuator 1,
No. 1 cannot be excited with primary longitudinal vibration and secondary bending vibration, and does not resonate. Therefore, the sliding projection 17 does not perform the operation of pushing the driven body 2, and the driven body 2 stops.

Switches 8-a, 8-b, 8-c, 8-
When all of d and 8-e output the resonance frequency signal as it is, the resonance frequency signal is input to the direction phase shifter 4, and
+ 90 ° or -90 ° depending on the moving direction of the driven body 2
It is output as a signal whose phase is shifted. The outputs of these switches 8-a, 8-b, 8-c, 8-d, 8-e are input to the power amplifier 5 either directly or via the directional phase shifter 4, and output to the ultrasonic actuator 1. The power to be supplied is amplified. Each of the amplified power signals is supplied to the A-phase or B-phase electromechanical transducer 12 of the ultrasonic actuator 1. Ultrasonic actuator 1 supplied with electric power
The first longitudinal vibration and the second bending vibration are excited in the resonator 11 to generate a standing wave elliptical vibration. Therefore, all five ultrasonic actuators 1-a, 1-b, 1-c, 1
In −d and 1-e, the sliding protrusion 17 pushes the driven body 2 to drive the driven body 2.

Switches 8-a, 8-b, 8-c, 8-
When any of d and 8-e outputs the resonance frequency signal as it is and the remaining switch 8 outputs 0 V, the ultrasonic actuator 1 of the group g corresponding to the switch 8 that has output the resonance frequency signal stands still. The driven body 2 is driven by the generation of the wave elliptical vibration, and the driven body 2 is not driven without the standing wave elliptical vibration generated by the ultrasonic actuators 1 of the group g corresponding to the switch 8 that outputs 0V. Therefore, the number of switches 8 that output the resonance frequency signal as it is is represented by x (x
= 1, 2, 3, 4), all switches 8-a,
8-b, 8-c, 8-d and 8-e have a thrust x / 5 as compared with the case where the resonance frequency signal is output as it is, and the driven body 2 is smoother and more precise by the mechanism described below. Can be controlled.

Here, it will be shown that the control by the switch 8, that is, the application controller 7 can be performed more smoothly and with higher precision. First,
All five ultrasonic actuators 1-
a, 1-b, 1-c, 1-d, 1-e, after driving the driven body 2 with the maximum thrust that can be generated, all five ultrasonic actuators 1-a, 1-b, 1-c, 1-d, 1
The case where -e stops driving the driven body 2 all at once will be described. In the prior art, since the application controller as shown in the first embodiment is not provided, all five ultrasonic actuators 1-a, 1-b, 1-c, 1-d, 1-e
From the state in which the driven body 2 is driven, suddenly all five ultrasonic actuators 1-a, 1-b, 1-c, 1-
d and 1-e stop driving the driven body 2 all at once, and the thrust changes suddenly from the maximum thrust to zero, and the driven body 2 cannot not only perform precise positioning but also vibrate due to the influence of inertia and the like. This can cause a situation.

However, as shown in the first embodiment, 5
Ultrasonic actuators 1-a, 1-b, 1-
From the state where c, 1-d, and 1-e are driving the driven body 2, the driving of the driven body 2 is stopped one by one by controlling the ultrasonic actuator 1 one by one by the switch 8 of the application controller 7. Finally, all five ultrasonic actuators 1-a,
When 1-b, 1-c, 1-d, and 1-e stop driving the driven body 2, the thrust gradually decreases from the maximum thrust and finally changes to zero. As a result, the influence of inertia and the like is eliminated as much as possible, precise positioning becomes possible, and generation of vibration can be suppressed. The procedure for gradually reducing the thrust depends on the system configuration and usage, etc.
Various procedures can be considered according to the procedure, but these can be realized by switching the switch 8 of the application controller 7 shown in the present embodiment.

As described above, according to the first embodiment of the present invention, in addition to the increase / decrease of the thrust due to the increase / decrease of the amount of power supplied by the resonance frequency signal generator 3, the five ultrasonic actuators 1
By using five switches 8-a, 8-b, 8-c, 8-d, 8-e for -a, 1-b, 1-c, 1-d, 1-e, Of the ultrasonic actuator 1 can be controlled, and the driven body 2 can be driven more smoothly and more accurately.

If the characteristic values of the individual ultrasonic actuators 1 are the same and generate the same thrust, in the case of the present embodiment, the number of ultrasonic actuators 1, which is five, is five. Since only one switch 8 is provided, the generated thrust can be changed every one-fifth step of the maximum thrust that can be generated, and the range of the generated thrust can be controlled with high precision by five steps.

Further, by changing the characteristic value of each ultrasonic actuator 1 and weighting the generated thrust, the range of the generated thrust can be accurately controlled with a smaller number of ultrasonic actuators 1. The following case will be described as an example. The reference ultrasonic actuator 1 is 1
And a thrust F is generated. In addition, 2 (= 2 ¹ ) times, 4
(= 2 ² ) times, 8 (= 2 ³ ) times thrust 2F, 4F, 8F
Is generated, and a total of four ultrasonic actuators 1 drive the driven body 2. Assuming that there are a total of four switches 8 provided for each ultrasonic actuator 1, the thrust generated by the four ultrasonic actuators 1 is 1/15 step of the maximum thrust 15F that can be generated, that is, the thrust F It is possible to change each time. When a thrust F is required to drive the driven body 2, only the switch 8 corresponding to the ultrasonic actuator 1 that generates the thrust F outputs a resonance frequency signal, and the other switches 8 output 0V. When a thrust 2F is required, only the switch 8 corresponding to the ultrasonic actuator 1 that generates the thrust 2F outputs a resonance frequency signal, and the other switches 8 output 0V. When the thrust 3F is required, only the two switches 8 corresponding to the ultrasonic actuators 1 that generate the thrust F and the thrust 2F output the resonance frequency signal, and the other two switches 8 output 0V. Similarly, by controlling in combination, four ultrasonic actuators 1 and four switches 8 can control with 16 steps (0, F, 2F,..., 15F) with high accuracy.

Second Embodiment A second embodiment of the present invention will be described with reference to FIG. FIG. 3 is a block diagram showing an overall configuration according to Embodiment 2 of the present invention. In FIG. 3, the same reference numerals 1, 2, 3, and 5 are assigned to the ultrasonic actuator, driven body, resonance frequency signal generation unit, and power amplifier that perform the same functions as those in FIG.

The quadrant phase shifter 10 is a component of the application controller 9 and shifts the phase by -90 °, 0 °, 90 °, and 180 ° with respect to the resonance frequency signal from the resonance frequency signal generation unit 3. And has two independent systems, output u and output v. The number of the ultrasonic actuators 1 is eight, and the number of the ultrasonic actuators 1 to which the same power is supplied at the same timing is two. Group g ₁ are six pieces of the ultrasonic actuator 1-a, 4-division phase shifter for generating a signal to be applied to the ultrasonic actuator 1-a 1
Output 0 u, group g ₂ consists of two certain ultrasonic actuator 1-b, the output of the quartered phase shifter 10 to generate a signal to be applied to the ultrasonic actuator 1-b is v
It is.

Next, a description will be given of a method of driving the ultrasonic actuator by the driving device having the above configuration. First, before operating the system, the maximum number of ultrasonic actuators 1 is determined based on the number of ultrasonic actuators 1 capable of optimal operation and the thrust necessary to drive the driven body 2 at a desired speed. Here, it is assumed that the number of the ultrasonic actuators 1 enabling the optimal operation is six, and the number of the maximum ultrasonic actuators 1 to be driven is eight. The optimal operation depends on the system configuration, application, and the like. Here, however, attention is paid to controlling vibration during positioning in position control of the driven body 2. In this case, eight ultrasonic actuators 1
To stop the driven body 2 from being driven by the maximum thrust that can be generated by the eight ultrasonic actuators 1
However, if the driving of the driven body 2 is stopped at the same time, vibration occurs at the time of positioning. Therefore, one step is provided in the middle of the change from eight drive to zero drive, and the number at that step is selected from 1 to 7. The method of selecting the number is determined by, for example, performing a trial run, and determining the number that minimizes vibration during positioning. As in the present embodiment described in the section of the structure, the number of the ultrasonic actuator of the group g ₁ is six,
The number of the ultrasonic actuator of the group g ₂ was determined to two.

Next, the operation of the system will be described.
When the resonance frequency signal is output from the resonance frequency signal generation unit 3, the resonance frequency signal is input to the power amplification unit 5 corresponding to the A phase of the ultrasonic actuators 1-a and 1-b, and the four-phase splitter 10
Is also entered. The output of the quadrant phase shifter 10 is input to the power amplifier 5 corresponding to the B phase of the ultrasonic actuators 1-a and 1-b.

If the outputs u and v of the four-phase splitter 10, that is, the respective B-phase signals are output with their phases shifted by 180 °, the resonators of all the ultrasonic actuators 1-a and 1-b are output. In 11, only the secondary bending vibration is excited, the primary longitudinal vibration cannot be excited, and the standing wave elliptical vibration cannot be generated. Therefore, the driven body 2 stops.

When both the outputs u and v of the four-phase splitter 10 output signals whose phases are shifted by + 90 ° or −90 ° in accordance with the moving direction of the driven body 2, the first embodiment of the present invention. Similarly, all the ultrasonic actuators 1-a and 1-a
In b, the primary longitudinal vibration and the secondary bending vibration are excited in the resonator 11, and the driven body 2 is driven with the maximum thrust.

One of the outputs u and v of the quadrant phase shifter 10 outputs a signal whose phase is shifted by + 90 ° or −90 ° in accordance with the moving direction of the driven body 2, and the other quadrant phase shifter 10 Is output with a phase shift of 180 ° with respect to the resonance frequency signal, there are a group that drives the driven body 2 and a group that does not drive the driven body 2, as in the first embodiment. A thrust to drive the driven body 2 can be generated with high accuracy. However, unlike the first embodiment,
Thrust changes are biased. This means that when the driven body 2 is driven at a desired speed, the required number of ultrasonic actuators 1 are driven by eight, but when the speed of the driven body 2 is changing, the changing process is performed. In this case, the ultrasonic actuator 1 is driven by the number of six which is optimally operated to mitigate the influence of a rapid change in thrust.

As described above, according to the second embodiment of the present invention, one ultrasonic actuator 1 is
By using the application controller 9 having the divided phase shifter 10 as a component, the thrust of each ultrasonic actuator 1 can be controlled, and the driven body 2 can be driven more smoothly and with higher precision.
Further, by deciding the number of the ultrasonic actuators 1 enabling the optimal operation before the system operation, the output terminals u,
The driven body 2 can be driven with higher accuracy by the minimum number of application controllers 9 having the four-phase splitter 10 having v as a constituent element.

[0042]

As described above, according to the present invention, even if the thrust is increased by arranging a plurality of ultrasonic actuators in the same direction, in addition to increasing the thrust by increasing or decreasing the amount of supplied electric power, a simple structure is provided. Accordingly, it is possible to provide a driving device and a driving method of an ultrasonic actuator that enable smooth and high-precision driving such as precise positioning of a driven body, suppression of uneven moving speed, suppression of vibration, and the like.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of the configuration of the present invention.

FIG. 2 is a diagram showing a configuration according to the first embodiment of the present invention.

FIG. 3 is a diagram showing a configuration according to a second embodiment of the present invention.

FIG. 4 is a perspective view showing the appearance of one conventional ultrasonic actuator.

FIG. 5 is a front view of a conventional ultrasonic actuator.

FIG. 6 is a side view of a conventional ultrasonic actuator.

FIG. 7 is a view showing longitudinal vibration of a conventional ultrasonic actuator.

FIG. 8 is a diagram showing bending vibration of a conventional ultrasonic actuator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ultrasonic actuator 2 Driven object 3 Resonance frequency signal generation part 4 Direction phase shifter 5 Power amplifying part 7, 9 Application controller 8 Switch 10 Four-phase splitter

Claims (6)

[Claims] 1. An electromechanical transducer having a substantially rectangular parallelepiped resonator and two electromechanical transducers fixed to the resonator, wherein high-frequency voltages having different phases are applied to the two electromechanical transducers. An ultrasonic actuator driving device that generates a standing wave elliptical vibration in a resonator and drives an ultrasonic actuator that drives a driven body pressed against the resonator by the standing wave elliptical vibration. A driving device for an ultrasonic actuator, comprising: a plurality of ultrasonic actuators; and an application controller for controlling driving of the plural ultrasonic actuators. 2. The ultrasonic actuator driving device according to claim 1, wherein the number of the application controllers is a divisor of the number of the ultrasonic actuators. 3. The ultrasonic actuator according to claim 2, wherein the ratio of the thrust for driving the driven body of the ultrasonic actuator is a power of two, and the number of the application controllers is the same as the number of the ultrasonic actuators. 2. A driving device for an ultrasonic actuator according to claim 1. 4. A resonator having a substantially rectangular parallelepiped shape and two electromechanical transducers fixed to the resonator, and applying high-frequency voltages having different phases to the two electromechanical transducers, respectively. A method of driving an ultrasonic actuator that generates a standing wave elliptical vibration in a resonator and drives an ultrasonic actuator that drives a driven body pressed against the resonator by the standing wave elliptical vibration, A method for driving an ultrasonic actuator, comprising: arranging a plurality of ultrasonic actuators in the same direction, and controlling the driving of the ultrasonic actuator at the plurality of positions by the application controller. 5. The ultrasonic actuators of a plurality of arrangements form a plurality of groups, power is supplied to the ultrasonic actuators of the same group at the same timing, and the number of the groups is a divisor of the number of the ultrasonic actuators. The driving method of the ultrasonic actuator according to claim 4, wherein: 6. A ratio of thrusts for driving a driven body of the ultrasonic actuator is a power of two, and driving and non-driving of the ultrasonic actuator are controlled in combination according to a required thrust. The method for driving an ultrasonic actuator according to claim 4, wherein