JP3352192B2 - Ultrasonic motor driving method and ultrasonic motor driving circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic motor driving method and an ultrasonic motor driving circuit , and more particularly, to a vibrator for generating ultrasonic vibration and a driven body moved with respect to the vibrator. For driving ultrasonic motor and ultrasonic
The present invention relates to a drive circuit for a wave motor .

[0002]

2. Description of the Related Art Various ultrasonic motors using an electromechanical energy conversion element such as a piezoelectric element as a driving source have been proposed.

An example of such a device is disclosed in Japanese Patent Application No. 4-321096 proposed by the present applicant. The one described in this publication uses two piezoelectric elements fixed to an elastic body as driving sources, generates longitudinal vibration and bending vibration in the elastic body, and combines these vibrations to generate ultrasonic elliptical vibration. The ultrasonic linear motor includes a vibrator and a driven member that is pressed by a part of the vibrator and moves relatively to the vibrator.

FIG. 19 shows this ultrasonic linear motor.
This will be described in more detail with reference to FIG. This ultrasonic linear motor is formed by pressing a driven member against an ultrasonic vibrator.

As shown in FIG. 19, the vibrator includes two laminated piezoelectric elements 101 and 10 on an upper end surface of an elastic body 100.
2 is sandwiched and fixed by three holding members 103, 104, and 105, and sliding members 106 and 107 are fixed to both ends of the lower end surface of the elastic body 100 by bonding.

[0006] As shown in FIG. 20, a linear guide 108, a guide rail 109, a holding frame 110,
The vibrator is held by a screw 111, a pressing force adjusting screw 112, a spring 113, and a slider holding member 114, and the sliding plate 115 is moved linearly in the horizontal direction. An ultrasonic linear motor is configured by pressing the members 106 and 107 so as to make frictional contact.

When the size of the vibrator is appropriately adjusted and an alternating voltage is applied to the laminated piezoelectric elements 101 and 102, a longitudinal resonance vibration as shown in FIG. 21 and a bending resonance vibration as shown in FIG. Occurs at the same time. When the phase difference between the voltages applied to the two laminated piezoelectric elements 101 and 102 is appropriately adjusted, these longitudinal vibration and bending vibration are combined, and elliptical vibration occurs at the antinode position of the bending vibration. The sliding members 106 and 107 are fixed to the portion that performs the elliptical movement,
When the sliding plate 115 is pressed against 06, 107, a driving force is generated on the sliding plate 115.

A conventional driving method of such an ultrasonic linear motor is as follows. In other words, the resonance frequency of the longitudinal vibration and the bending vibration of the vibrator matches the resonance frequency of the laminated piezoelectric element.
An alternating voltage of about 0 V (peak to peak) is applied. At this time, when the phase difference between the alternating voltages applied to the two laminated piezoelectric elements is set to +90 degrees with respect to one piezoelectric element, the ultrasonic linear motor Moves to one side, and the moving direction of the ultrasonic linear motor is reversed by setting the phase difference between the alternating voltage of one piezoelectric element and the other to -90 degrees.

Further, the ultrasonic linear motor has a maximum speed of about 100 mm / s to 150 mm / s by actual measurement, furthermore, a response at the time of starting (from a speed of 0 to a predetermined speed) and a time of stopping. Is also fast (from a predetermined speed to a speed of 0).

[0010]

However, in general, when an object is operated / stopped (step response) at a high speed, FIG.
As shown in (1), a vibration peculiar to the system centering on the stop position occurs.

For this reason, when positioning is performed by simply turning on / off the application of voltage by the ultrasonic linear motor, there is a problem that a large vibration is generated due to a quick response of the moving body. Further, there is a possibility that the fixed portion also vibrates due to a reaction of the operation of the moving body.

Further, in the above-mentioned ultrasonic linear motor, high-speed response is possible, but low-speed operation is difficult. Therefore,
In order to operate the ultrasonic linear motor at low speed, for example, as shown in FIG. 14, the actual movement shown by the solid line is stepwise repeated in a small amount with respect to the target movement shown by the broken line. I had to do it.

In this case as well, there is a problem that the above-mentioned minute natural vibration is generated at each stage, and the device always operates while vibrating.

The present invention has been made in view of the above circumstances, and has an efficient ultrasonic motor driving method and an ultrasonic motor capable of minimizing unnecessary vibrations generated in a driven body.
It is an object of the present invention to provide a drive circuit for a wave motor .

[0015]

Means for Solving the Problems To achieve the above object,
First, the driving method of the first ultrasonic motor according to the present invention is as follows.
Elastic body and electro-mechanical energy fixed to the elastic body
A conversion element, said electro-mechanical energy conversion element
Ultrasonic vibration is generated on the surface by applying a drive signal to
A vibrator to be produced, and a pressure contacting surface of the vibrator;
Driven body moved with respect to the vibrator by acoustic vibration
The method for driving an ultrasonic motor, comprising:
With a period of less than half the period of the natural vibration of the moving body
Intermittently, drive signals are transmitted to the electro-mechanical energy conversion element.
Signal and reduce at least the natural vibration at the time of stop.
The deceleration control is performed when stopping to
You. In order to achieve the above object, the second aspect of the present invention
The driving method of the ultrasonic motor is as follows.
In the driving method, the electro-mechanical energy conversion element
Are two piezoelectric elements, and these two piezoelectric elements are
So that the direction of expansion and contraction is parallel to the direction of movement of the driven body.
Characterized by being arranged in Achieve the above objectives
To drive the third ultrasonic motor according to the present invention.
The method is based on the driving method of the first or second ultrasonic motor.
By changing the voltage amplitude of the drive signal,
The moving speed of the driven body is controlled. Up
To achieve the above object, a fourth ultrasonic wave according to the present invention
The method of driving the motor is the same as that of the first or second ultrasonic motor.
In the method for driving a motor, the application time
The moving speed can be controlled by changing the tee ratio.
And features. In order to achieve the above object, the present invention
The driving method of the fifth ultrasonic motor according to
Is a driving method of the second ultrasonic motor, wherein the driving signal is
The moving speed is controlled by changing the frequency of the signal
It is characterized by the following. To achieve the above objectives,
A sixth driving method of the ultrasonic motor according to Akira
An electro-mechanical energy conversion element fixed to the elastic body;
A driving signal is supplied to the electro-mechanical energy conversion element.
To generate ultrasonic vibrations on the surface by applying
The rotor and the surface of the vibrator are pressed against the ultrasonic vibration.
And a driven body that is moved with respect to the vibrator.
And have your method of driving the ultrasonic motor, the driven body is Yusuke
Cycle of less than half the cycle of natural vibration
Intermittently with a cycle smaller than the cycle of 1/2 or less
Drive signal to the electro-mechanical energy conversion element
And at least to reduce the natural vibrations when stopping
In addition, deceleration control is performed at the time of stop. above
To achieve an object, a seventh ultrasonic mode according to the present invention is provided.
The driving method of the motor is the same as the driving method of the sixth ultrasonic motor.
Here, the deceleration control includes an application time duration of the drive signal.
25%, 20%, 15%, 10%, 5%
It is characterized by changing. Achieve the above objectives
First, the driving circuit of the first ultrasonic motor according to the present invention includes:
Elastic body and electro-mechanical energy fixed to the elastic body
A conversion element, said electro-mechanical energy conversion element
Ultrasonic vibration is generated on the surface by applying a drive signal to
A vibrator to be produced, and a pressure contacting surface of the vibrator;
Driven body moved with respect to the vibrator by acoustic vibration
In the drive circuit of the ultrasonic motor having
And the phase of ± 90 degrees in response to the output of the first oscillator
A difference is generated to excite the vibrator of the ultrasonic motor.
A phase shifter for generating an alternating voltage having a wave number;
A first power amplifier for amplifying an output voltage of the phase shifter;
A second power amplifier for amplifying the output voltage of the first and second power amplifiers;
And the output voltage from the second power amplifier is amplitude-modulated,
The second driving the ultrasonic motor with the modulated output voltage
And an oscillator of the natural vibration of the driven body
Said electro-mechanical intermittently at a period of not more than half the period
While applying a drive signal to the energy conversion element,
At least decelerate at stop to reduce natural vibration at stop
The control is performed. Achieve the above objectives
First, the driving circuit of the second ultrasonic motor according to the present invention includes:
In the first ultrasonic motor drive circuit, the second ultrasonic motor
Changing the voltage amplitude of the drive signal
Controlling the moving speed of the driven body with
You. In order to achieve the above object, a third aspect of the present invention
The drive circuit of the ultrasonic motor is the same as that of the first ultrasonic motor.
In the driving circuit, the second oscillator generates the driving signal
By changing the application time duty ratio,
Characterized in that control the moving speed of the moving object. Eyes above
Fourth ultrasonic motor according to the present invention to achieve the target
The drive circuit of the first embodiment is the same as the drive circuit of the first ultrasonic motor.
And the second oscillator changes the frequency of the drive signal.
Controlling the moving speed of the driven body by
It is characterized by. In order to achieve the above object, the present invention
The fifth ultrasonic motor drive circuit comprises an elastic body and the elastic body.
From electro-mechanical energy conversion element fixed to
A drive signal is applied to the electro-mechanical energy conversion element.
Vibrator that generates ultrasonic vibration on the surface by applying
Is pressed against the surface of the vibrator, and the ultrasonic vibration
Ultrasonic wave provided with driven body moved with respect to the vibrator
In a motor driving circuit, an oscillator and an output of the oscillator are provided.
Generates a phase difference of ± 90 degrees under the force
Generates an alternating voltage at a frequency that excites the motor oscillator
Phase shifter and first power for amplifying the output voltage of the oscillator
Amplifier and second power for amplifying the output voltage of the phase shifter
Determining the output frequency of the amplifier and the oscillator;
Arbitrarily sweep the frequency band including the operating frequency of the ultrasonic motor
Frequency control means for pulling, the driven body has
Intermittently at a period of less than half the period of the natural vibration
Applying a drive signal to the electro-mechanical energy conversion element
Together with at least
When the vehicle stops, deceleration control is performed.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 15 show a first embodiment of the present invention. The drive circuit of the ultrasonic motor according to the present embodiment is as shown in the block diagram of FIG.

That is, the driving circuit of the ultrasonic motor includes a first oscillator 1, a phase shifter 2 which receives the output of the first oscillator 1 and generates a phase difference of ± 90 degrees, A power amplifier 3 for amplifying the output voltage of the oscillator 1, a power amplifier 4 for amplifying the output voltage of the phase shifter 2, and an ultrasonic linear motor 5 (hereinafter referred to as a drive) driven by the output voltages from the power amplifiers 3 and 4. Motor 5). Further, the drive circuit of the ultrasonic motor converts the output voltages of the first oscillator 1 and the phase shifter 2 into the second oscillator 6
To perform amplitude modulation (AM modulation).

The motor 5 and an ultrasonic vibrator (not shown) used for driving the motor 5 are shown in FIGS.
This is the same as the conventional example described with reference to FIG.

Next, the operation of this embodiment will be described. First
The oscillator 1 and the phase shifter 2 generate an alternating voltage having a frequency for exciting the ultrasonic vibrator of the motor 5. The amplitude of the voltage applied to the motor 5 can be amplitude-modulated by the second oscillator 6, that is, can be arbitrarily changed by the output waveform of the second oscillator 6. That is,
By setting the output of the second oscillator 6 to a rectangular wave whose duty can be arbitrarily changed, as shown in FIG. 2A, for example, the frequency voltage for exciting the ultrasonic vibrator becomes as shown in FIG. Are subjected to pulse width modulation (PWM) as shown in FIG.

Here, it is assumed that the second oscillator 6 outputs a waveform whose frequency is fixed to a predetermined value and whose duty is gradually increased or decreased.

As described above, in the ultrasonic motor, high-speed response is possible, but low-speed operation is difficult. Therefore, in order to operate the ultrasonic motor at a low speed, a target motion indicated by a broken line as shown in FIG. The low-speed movement of the driven body is realized by performing a stepwise operation in which the operation and the stop are repeated by a small amount as shown by a solid line. For this purpose, a voltage is applied to the motor 5 in a pulsed manner.

The operation of the motor 5 according to the ultrasonic motor driving method according to the present embodiment will be described below based on experimental results. 3 to 7 show that the application time per one voltage application is about 16 times.
The state of displacement of the motor 5 when the voltage application cycle (voltage application time interval) is variously changed while being fixed to 0 μs is observed with an oscilloscope. The voltage application cycle is 3.3 ms in FIG. 3, 2 ms in FIG. 4, and 1.4 in FIG.
ms, FIG. 6 is set to 1.1 ms, and FIG. 7 is set to 0.9 ms.

In each figure, the pulse-like waveforms shown in the upper two rows show the voltage applied to the motor 5, and the finely oscillating waveform shown in the lower row shows the output of the displacement meter.

More specifically, the waveform of the voltage applied to the motor 5 has a waveform as shown in FIG. 8, and looks like a pulse as shown in FIGS. 3 to 7 because of the oscilloscope sweep time. Things. The portion where the displacement waveform looks thick is due to high frequency noise of the displacement meter used for the measurement.

When observing FIGS. 3 to 8, first, in FIGS. 3 to 5, the state in which the motor 5 oscillates in the displacement direction according to the voltage application cycle (voltage application time interval). Is observed. When this state is as shown in FIG. 6, the motor 5 performs a constant movement with almost no shaking regardless of the voltage application cycle. Further, in the state shown in FIG. 7, it can be seen that the motor 5 moves smoothly without shaking while the motor 5 is being driven, and that the motor 5 is slightly shaking in the last stop operation of the movement. As is clear from the figures, when the voltage application cycle is set to about 1 ms, the vibration when the motor 5 is moved is almost eliminated.

Next, the reason why the vibration disappears will be described. When a voltage is applied to the motor 5 only once, as shown in FIG.
Only phases are shown. In the case of the moving body (driven body) of the motor 5 used in the experiment, it is shown in FIG. 9 (or a schematic diagram in which the main part of FIG. 9 is taken out is as shown in FIG. 15). About 500Hz (period 2m
It is observed that the natural vibration of s) is performed.

When the voltage application for a very short time is repeated, a time interval for applying these voltages, that is, as shown in FIG.
The interval (voltage application cycle) between the displacement start positions 3 is shown in FIG.
If it is long as shown in (A), the natural vibration that attenuates is performed between the displacement start position 1 and the displacement start position 2, and the same applies sequentially between the displacement start position 2 and the displacement start position 3 in the following. The natural vibration is attenuated.

As shown in FIG. 10B, when the voltage application cycle becomes slightly short and becomes medium, the cycle of the natural vibration becomes about 5
Since the frequency is constant at 00 Hz, the number of times of vibration during one damping vibration is reduced.

When the voltage application cycle is further shortened, FIG.
As shown in (C), the next displacement operation is performed before the damping natural vibration occurs, and consequently, no vibration occurs during the movement. The voltage application cycle at this time is the interval between the displacement start positions 1, 2, 3 and the peak positions 1 ', 2', 3 'of the displacement (vibration), that is, one cycle of the natural vibration period
/ 2 or less, and in experiments, 1/2 of the natural oscillation period of 2 ms
It was observed that 1 ms, which is a condition under which vibration hardly occurs, was satisfied.

However, even in this case, as shown in FIG. 7, the vibration at the final step (when stopped) still remains. In this regard, deceleration may be gradually performed before reaching the final step. That is,
It is generally known that acceleration and deceleration should be gradually performed to reduce natural vibration when starting or stopping movement.

Therefore, it is necessary to control the speed by some means. However, an attempt was made to control the speed by changing the width of the drive pulse applied to the motor 5. FIG. 11 shows the results of this experiment.

As shown in the figure, it has been experimentally confirmed that the smaller the pulse width, the lower the speed. That is, the moving speed of the driven body monotonically increases with the increase of the pulse width, and is connected by a smooth curve. I found out.

Based on these results, the duty of the pulse is set to 5%, 10%, 15%, 20%, 25%, 25%.
FIG. 12 shows a state when the displacement is made while changing the percentage (%, 20%, 15%, 10%, 5%) (that is, when the driven body is gradually accelerated and gradually decelerated). As is clear from the figure, it can be seen that the vibration at the time of stop is reduced, and an extremely smooth displacement is obtained.

As described above, according to the first embodiment, a half of the period of the natural vibration of the moving body is set.
The drive voltage is applied to the ultrasonic motor intermittently at a cycle of twice or less, and the voltage application time per one time of the intermittent voltage application is adjusted, and the energy applied to the motor is controlled to drive the driven body. By gradually accelerating and decelerating, unnecessary vibration can be greatly reduced, and an efficient ultrasonic motor can be obtained.

In the above description, the moving speed of the driven body is controlled by changing the pulse width. As a modification, it is possible to control the moving speed of the driven body by changing the voltage amplitude while keeping the pulse width constant. The relationship between the voltage amplitude and the moving speed is as shown in FIG. 13. When the amplitude is small, the speed does not move. However, when the amplitude exceeds a certain value, the speed monotonically increases as the amplitude increases. become. Therefore, by using the portion where the amplitude and the speed are monotonically increasing, the time (pulse width) for applying the voltage is fixed,
The speed can be controlled by changing the amplitude of the voltage applied intermittently, and the same result as described above can be obtained.

FIGS. 16 to 18 show a second embodiment of the present invention. In the second embodiment, the description of the same parts as those in the first embodiment is omitted,
Only the differences will be mainly described. The drive circuit of the ultrasonic motor according to the second embodiment, as shown in FIG.
An oscillator 11, a phase shifter 12 for generating a phase difference of ± 90 degrees upon receiving an output of the oscillator 11, a power amplifier 13 for amplifying an output voltage of the oscillator 11,
And an ultrasonic linear motor 15 (hereinafter, referred to as a motor 15) driven by the output voltages from the power amplifiers 13 and 14. Further, in the drive circuit of the ultrasonic motor, the output frequency of the oscillator 11 is determined by the frequency control means 16.

The motor 15 and the ultrasonic vibrator (not shown) used for driving the motor 15 are the same as those in the above-described conventional example described with reference to FIGS.

Next, the operation of the second embodiment will be described. The motor 15 is controlled by the oscillator 11 and the phase shifter 12.
Generates an alternating voltage having a frequency that excites the vibrator. The frequency band including the movable frequency of the motor 15 can be arbitrarily swept by the frequency control means 16.

FIG. 18 shows an experimental result of the moving speed of the motor 15 when the driving frequency is swept. FIG. 18 (A) shows a speed curve when sweeping from a low frequency to a high frequency. The moving speed is 0 except for a sharp peak near a frequency of 55 kHz, and a pulse-like moving speed is obtained. ing. Then, both ends of the peak are almost asymptotically converged to the moving speed 0.

FIG. 18B shows a speed curve when the frequency is swept from a high frequency to a low frequency. As shown in FIG. 18A, the moving speed is 0 except for a sharp peak near a frequency of 55 kHz. And both ends of the peak are almost asymptotically converged to the moving speed 0.

Thus, in any case of FIGS. 18A and 18B, it can be seen that the motor 15 operates only in a specific frequency band. Therefore, by sweeping the oscillation frequency of the oscillator 10 at predetermined time intervals, it is possible to cause the motor 15 to generate a driving force intermittently.

In the method of driving the motor 15 by sweeping the frequency band using such a property that the motor 15 operates only near a specific frequency, the moving speed is controlled by changing the sweep speed. It can be carried out.

That is, as shown in FIG. 17A, by reducing the sweep speed, the effective drive time (movable time) of the motor 5 can be increased, thereby increasing the moving speed. Can be.

Conversely, as shown in FIG. 17B, by increasing the sweep speed, the effective driving time of the motor 5 can be shortened, and thereby the moving speed can be reduced.

As described above, according to the second embodiment, the frequency sweep is performed at a cycle (time interval for performing the sweep) equal to or less than 1/2 of the natural oscillation cycle of the moving body, and the sweep speed is gradually reduced. In this case, almost the same effect as the method of intermittently applying the driving voltage and gradually changing the driving time per one operation as described in the first embodiment can be obtained, and unnecessary vibration can be reduced. And an efficient ultrasonic motor can be obtained.

Further, even if the resonance frequency of the vibrator of the motor 15 fluctuates due to temperature fluctuation or the like, the frequency sweep width is widened in consideration of the fluctuation, so that the operation is not stopped.

If the output of the oscillator 11 is stopped during the time from the end of the frequency sweep to the start of the next sweep, the power consumption can be further reduced, and the efficiency can be further improved. It can be a sound wave motor.

[0048]

As described above, according to the present invention, an efficient ultrasonic motor driving method and an ultrasonic motor capable of minimizing unnecessary vibration generated in a driven body.
Can be provided .

[Brief description of the drawings]

FIG. 1 is a block diagram showing a driving circuit of an ultrasonic motor according to a first embodiment of the present invention.

FIG. 2 is a diagram showing (A) an output of a second oscillator and (B) a frequency voltage for exciting an ultrasonic vibrator in driving the ultrasonic motor according to the first embodiment.

FIG. 3 is a diagram showing a state of displacement when a drive pulse having a voltage application period of 3.3 ms is applied to the ultrasonic motor of the first embodiment.

FIG. 4 is a diagram showing a state of displacement when a drive pulse having a voltage application cycle of 2 ms is applied to the ultrasonic motor of the first embodiment.

FIG. 5 is a diagram showing a state of displacement when a drive pulse having a voltage application cycle of 1.4 ms is applied to the ultrasonic motor of the first embodiment.

FIG. 6 is a diagram showing a state of displacement when a drive pulse having a voltage application period of 1.1 ms is applied to the ultrasonic motor of the first embodiment.

FIG. 7 is a diagram showing a state of displacement when a drive pulse having a voltage application cycle of 0.9 ms is applied to the ultrasonic motor of the first embodiment.

FIG. 8 is an enlarged diagram showing details of a drive pulse applied to the ultrasonic motor of the first embodiment.

FIG. 9 is a diagram showing a natural vibration generated when a one-pulse drive voltage is applied to the ultrasonic motor of the first embodiment.

FIG. 10 is a diagram showing a state in which a natural vibration is generated when a voltage is applied to the ultrasonic motor of the first embodiment at a long period (A), a medium period (B), and a short period (C). FIG.

FIG. 11 is a diagram showing a change in speed of a driven body when a pulse width of a pulse voltage applied to the ultrasonic motor of the first embodiment is changed.

FIG. 12 is a diagram showing a state of displacement of a driven body when a pulse width of a pulse voltage applied to the ultrasonic motor according to the first embodiment is first gradually increased and then reduced.

FIG. 13 is a diagram showing a change in the speed of the driven body when the amplitude of the pulse voltage applied to the ultrasonic motor of the first embodiment is changed.

FIG. 14 is a diagram showing a target movement and an actual movement when a gentle displacement is caused in the ultrasonic motor of the first embodiment.

FIG. 15 is a diagram schematically illustrating a state of natural vibration generated when a voltage is applied to the ultrasonic motor of the first embodiment.

FIG. 16 is a block diagram showing a driving circuit of an ultrasonic motor according to a second embodiment of the present invention.

FIG. 17 is a diagram showing changes in the movable time when the frequency of the voltage applied to the ultrasonic motor of the second embodiment is (A) gently swept and (B) suddenly swept.

FIG. 18 (A) When the voltage applied to the ultrasonic motor of the second embodiment is swept from low frequency to high frequency,
(B) The diagram which shows the speed curve at the time of sweeping from a high frequency to a low frequency, respectively.

FIG. 19 is a perspective view showing a conventional ultrasonic transducer.

FIG. 20 is a front view showing a conventional ultrasonic linear motor.

FIG. 21 is a view showing longitudinal resonance vibration of a conventional ultrasonic transducer.

FIG. 22 is a view showing bending resonance vibration of a conventional ultrasonic transducer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... First oscillator 2, 12 ... Phase shifter 3, 4, 13, 14 ... Power amplifier 5, 15 ... Motor 6 ... Second oscillator 11 ... Oscillator 16 ... Frequency control means

Claims (12)

(57) [Claims] A vibrator comprising an elastic body and an electro-mechanical energy conversion element fixed to the elastic body, and applying a drive signal to the electro-mechanical energy conversion element to generate ultrasonic vibration on the surface. And a driven body that is pressed against the surface of the vibrator and is moved with respect to the vibrator by the ultrasonic vibration. The driving method of the ultrasonic motor, comprising: A drive signal is intermittently applied to the electro-mechanical energy conversion element at a cycle of 1/2 or less , and at least
A method for driving an ultrasonic motor, comprising: performing deceleration control when stopped to reduce vibration . 2. The electro-mechanical energy conversion element is two piezoelectric elements , and the two piezoelectric elements are arranged such that their expansion and contraction directions are parallel to the moving direction of the driven body. The method for driving an ultrasonic motor according to claim 1, wherein: 3. The method of driving an ultrasonic motor according to claim 1, wherein a moving speed of the driven body is controlled by changing a voltage amplitude of the driving signal. 4. An application time duty ratio of the drive signal,
The moving speed of the driven body can be controlled by changing
The ultrasonic motor according to claim 1 or 2, wherein
Drive method. 5. The method according to claim 5, wherein a frequency of the driving signal is changed.
A moving speed of the driven body is controlled.
3. A method for driving an ultrasonic motor according to claim 1 or 2. 6. An elastic body and an electric machine fixed to said elastic body.
The electro-mechanical energy conversion element.
By applying a drive signal to the energy conversion element,
A vibrator for generating sonic vibrations and pressure contact with the surface of the vibrator
Moved with respect to the vibrator by the ultrasonic vibration.
Method for driving an ultrasonic motor comprising a driven body to be driven
Te, following 1 times the half of the period of natural vibration the driven body has
With a period of less than half the period
The electro-mechanical energy conversion element intermittently in small cycles
The drive signal is applied to the
When stopping, perform deceleration control to reduce vibration.
Characteristic driving method of ultrasonic motor. 7. The deceleration control according to claim 6, wherein the deceleration control includes an application time of the drive signal.
Duty ratio 25%, 20%, 15%, 10%, 5
%.
Drive method of wave motor. 8. An elastic body and an electric machine fixed to the elastic body.
The electro-mechanical energy conversion element.
By applying a drive signal to the energy conversion element,
A vibrator for generating sonic vibrations and pressure contact with the surface of the vibrator
Moved with respect to the vibrator by the ultrasonic vibration.
Of the ultrasonic motor drive circuit provided with the driven body
Te, a first oscillator, a phase difference of 90 degrees ± receiving the output of said first oscillator originating
Of the frequency for exciting the vibrator of the ultrasonic motor.
A phase shifter for generating an alternating voltage, and a first power amplifier for amplifying an output voltage of the first oscillator
, A second power amplifier for amplifying an output voltage of the phase shifter , and an amplitude changer for output voltages from the first and second power amplifiers.
Drive the ultrasonic motor with the amplitude-modulated output voltage.
It comprises a second oscillator for movement, the following 1 times the half of the period of natural vibration the driven body has
Intermittently at the cycle of
Apply the drive signal and at least the
It features deceleration control when stopped to reduce movement
The driving circuit of the ultrasonic motor. 9. The driving circuit according to claim 8, wherein the second oscillator is configured to control a voltage of the driving signal.
Controlling the moving speed of the driven body by changing the amplitude
The ultrasonic motor according to claim 8, wherein
Drive circuit. 10. The driving circuit according to claim 5, wherein the second oscillator is configured to output the signal of the driving signal.
The driven body is changed by changing an additive duty ratio.
The moving speed of the object is controlled.
Ultrasonic motor drive circuit. 11. The driving circuit according to claim 1, wherein the second oscillator is configured to control a frequency of the driving signal.
Controlling the moving speed of the driven body by changing the wave number
The ultrasonic motor according to claim 8, wherein
Drive circuit. 12. An elastic body and electricity fixed to said elastic body.
The electrical-mechanical energy conversion element.
By applying a drive signal to the
A vibrator for generating ultrasonic vibration and pressure applied to the surface of the vibrator
Touched and moved with respect to the vibrator by the ultrasonic vibration
In the drive circuit of the ultrasonic motor provided with the driven body
Receiving the output of the oscillator and the oscillator, and generating a phase difference of ± 90 degrees.
Of the frequency to excite the vibrator of the ultrasonic linear motor.
A phase shifter for generating a second voltage, a first power amplifier for amplifying the output voltage of the oscillator , a second power amplifier for amplifying the output voltage of the phase shifter, and determining an output frequency of the oscillator. With ultrasonic mode
Frequency arbitrarily sweeps the frequency band including the movable frequency of the
Number control means, and is not more than half the period of the natural vibration of the driven body
Intermittently at the cycle of
Apply the drive signal and at least the
It features deceleration control when stopped to reduce movement
Ultrasonic motors of the drive circuit to.