JP2003153559A - Oscillatory wave motor drive controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To extend the life of an oscillatory wave motor by applying AC sine waves of little distortion to a piezoelectric body, discouraging biased abrasion on a stator. SOLUTION: A sine wave oscillator 20a oscillates a sine wave with frequency corresponding to the objective speed, and finely adjusts the frequency of generated sine waves, based on the quantity of increase and decrease of the frequency being decided based on the speed difference between the objective speed and the detected speed. Moreover, a PWM 21a generates reference waves based on the pulse width corresponding to the objective speed, and generates a PWM signal based on the reference waves and the sine waves outputted from the sine wave oscillator 20a. Then, a pulse generator 12 generates a plurality of pulse signals different in phase based on this PWM signal, and a booster 13 generates a drive signal for driving the oscillatory motor 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration wave motor drive control device, and more particularly to applying a frequency signal to an electro-mechanical energy conversion element to excite the electro-mechanical energy conversion element to obtain a driving force. The present invention relates to a drive control device for a vibration wave motor.

The above-mentioned vibration wave motor drive control device is included in an image forming apparatus which constitutes, for example, a copying machine, a printer, a facsimile machine or the like.

[0003]

2. Description of the Related Art Generally, an electric-mechanical energy conversion element, a vibrating body, and the like are used. By applying a frequency signal to the electric-mechanical energy conversion element (piezoelectric body), the vibrating body is excited to obtain a driving force. Known vibration wave motors.

FIG. 8 is a block diagram showing the configuration of a conventional drive control device used to drive and control such a vibration wave motor.

In the figure, a target value command unit 30 and a power supply unit 31 are components outside the vibration wave motor drive control device, and a speed command is input from the target value command unit 30 to the vibration wave motor drive control device. Although the standard speed v [rpm] is the command speed (target speed) of the vibration wave motor 14, here the speed v [rpm] is input to the vibration wave motor drive control device as the speed command, and the pulse width setting unit 11 And speed difference detector 1
Suppose that it was sent to 6 and.

A speed-pulse width correspondence table indicating a pulse width corresponding to a commanded speed is preset in the pulse width setting section 11, and the pulse width setting section 11 sets the pulse width corresponding to the input speed v. Is read from the table and sent to the pulse generator 12.

The speed-pulse width correspondence table is set according to the characteristic peculiar to the vibration wave motor 14. In addition, the drive control device shown in FIG.
However, when one drive control device controls a plurality of vibration wave motors, the drive control device includes a plurality of tables corresponding to the respective vibration wave motors.

The pulse generator 12 includes a pulse width setting section 11
4 phase pulse signals A1 and A based on the pulse width sent from
2, A3, A4, B1, B2, B3, B4 are generated.

FIG. 9 shows a four-phase pulse signal A1, A2, A.
3 is a timing chart showing A3, A4, B1, B2, B3 and B4.

The pulse generator 12 includes a pulse width setting section 11
Pulse signals A1, A2, A3, A4, B1, B2, B3, B whose pulse widths are the pulse widths sent from
4 is generated. Then, the pulse signal A1 and the pulse signal A
2 and a pulse signal B1 and a pulse signal B2 are provided with a phase difference of 180 °, respectively.
And the pulse signal B1 and the pulse signal A2 and the pulse signal B2 are provided with a phase difference of 90 °.

Four-phase pulse signals A1, A2, A3, A4, B1, B2, B3 output from the pulse generator 12
B4 is input to the booster 13.

FIG. 10 is a circuit diagram showing the internal structure of the booster 13.

The step-up unit 13 is provided with the voltage from the pulse generator 12.
Phase pulse signals A1, A2, A3, A4, B1, B2
A for driving the vibration wave motor 14 based on B3 and B4
Phase and -A phase, B phase, and -B phase AC waves are generated. The AC waves of the A phase, -A phase, B phase, and -B phase are drive voltage signals having the same frequency and a phase difference of 90 °, and the voltage amplitude is about 300V.

In FIG. 10, 27a, 27b, 27c,
27d, 27e, 27f, 27g and 27h are switching FETs. FET27a and FET27b are A
FET for generating a phase drive signal, and FET27c and FE
T27d is an FET for generating a -A phase drive signal,
T27e and FET27f are FETs for generating a B-phase drive signal
The FET 27g and the FET 27h are FETs for generating the -B phase drive signal.

28a, 28b, 28c, 28d are transformers with a center tap. The center tap electrode on the primary side of the transformer 28a is connected to the power supply voltage.
The power supply voltage is a DC voltage generated by the power supply unit 31 including a switching regulator or the like. 24V as an example
Is used. On the primary side of the transformer 28a, the FET 27 is provided on each of the two electrodes other than the center tap electrode.
The drains of a and 27b are connected. The FET 27 is generated by the pulse signal A1 output from the pulse generator 12.
a is driven, and the FET 27b is driven by the pulse signal A2. As a result, a current alternately flows from the center tap electrode to the other two electrodes on the primary side of the transformer 28a. A transformer 2 is provided on the secondary side of the transformer 28a.
An AC signal corresponding to the boosting rate of 8 is generated. This becomes the A-phase AC wave output. Similarly, -A phase AC wave output, B phase AC wave output, and -B phase AC wave output are also generated.

A four-phase pulse signal A as described with reference to FIG.
FE for 1, A2, A3, A4, B1, B2, B3, B4
By using each as a gate signal of T27a to 27h, the A-phase AC wave output and the B-phase AC wave output of FIG. 10 become signals having a phase difference of 90 °. Such A phase AC wave output, -A phase AC wave output, B phase AC wave output and -B
The phase AC wave output is input to the vibration wave motor 14 of FIG.

Returning to FIG. 8, in the vibration wave motor 14, the A-phase and B-phase AC wave signals having such a phase difference of 90 ° are applied to the electric-mechanical energy conversion element (piezoelectric body) to vibrate. A traveling wave is generated in the body, which causes the rotating body to rotate.

Reference numeral 16 denotes a speed difference detection unit, which detects the rotation speed of the vibration wave motor 14 based on pulse information obtained from an encoder 15 connected to the output shaft of the vibration wave motor 14. Then, the speed difference Δv between the detected rotation speed and the command speed previously sent from the target value command unit 30 is detected and output to the frequency setting unit 17.

Frequency setting unit 17 to which the speed difference Δv is input
Creates a frequency increasing / decreasing manipulated variable according to the speed difference Δv.
Specifically, since control is performed in a frequency range higher than the resonance frequency, if the detected rotation speed is faster than the command speed, the frequency increase / decrease operation amount that changes the frequency to the higher side and to the lower frequency is created. Then, the detected rotation speed is set so as to approach the commanded speed, and the detected rotation speed is sent to the pulse generator 12. The pulse generator 12 has four-phase pulse signals A1, A2, A3, A based on the frequency increasing / decreasing manipulated variable obtained by the frequency setting unit 17.
4, B1, B2, B3, B4 are created.

In this way, the closed loop control is performed, and the rotation speed of the vibration wave motor 14 converges to the command speed at the control speed according to the control parameter.

Here, in addition to the drive frequency as an operation amount for controlling the rotation speed of the vibration wave motor 14, four-phase pulse signals A1, A2, A3, A4, B1, B2, B3 are provided.
The pulse width of B4 is used. That is, in general, when the frequency of the applied AC voltage is changed, the rotation speed of the vibration wave motor has a peak at the resonance frequency fr of the vibration wave motor, and has a gentle characteristic in a frequency range higher than the resonance frequency fr. Therefore, the rotation speed of the vibration wave motor is controlled by changing the frequency in a frequency range higher than the resonance frequency fr, which is usually relatively easy to control.

By the way, such characteristics have four-phase pulse signals A1, A2, A3, A4, B1, B2, B3, B4.
Is a characteristic when the pulse width is constant, and when the pulse width is changed, the characteristic curve itself shifts. Specifically, when the pulse width is set large, the characteristic curve shifts in the direction in which the rotation speed increases even at the same frequency, and when the pulse width is set small, the characteristic curve shifts in the direction in which the rotation speed decreases even at the same frequency. .

Then, the pulse width setting unit 11 refers to the speed-pulse width correspondence table and refers to the command speed v in the frequency region where the energy conversion efficiency of the vibration wave motor 14 is high.
Select the frequency corresponding to. At that time, when the corresponding frequencies exist in a plurality of different pulse widths, for example, the frequency having the smaller pulse width is selected. The frequency and pulse width thus obtained are output to the pulse generator 12.

Thus, in addition to the frequency of the applied AC voltage, the pulse width of the four-phase pulse signal is used as the control manipulated variable to control the rotational speed of the vibration wave motor 14 at the target speed.

[0025]

However, in the conventional vibration wave motor drive control device, the waveform of the AC wave signal applied to the electric-mechanical energy conversion element (piezoelectric body) of the vibration wave motor 14 is an accurate sine wave. It is not distorted. Therefore, there is a possibility that unevenness occurs in the traveling wave, and uneven wear occurs in the stator forming the vibration wave motor 14 based on the unevenness, which shortens the life of the vibration wave motor 14.

The present invention has been made in view of the above problems, and by applying an AC sine wave with less distortion to the piezoelectric body, uneven wear is less likely to occur in the stator, and the length of the vibration wave motor is reduced. It is an object of the present invention to provide a vibration wave motor drive control device that has a long life.

[0027]

In order to achieve the above object, according to the invention of claim 1, the electro-mechanical energy conversion element is excited by applying a frequency signal to the electro-mechanical energy conversion element. In a drive control device for a vibration wave motor that obtains a driving force, an encoder that detects an operation speed of the vibration wave motor, a speed difference between an operation speed detected by the encoder, and a target speed of the vibration wave motor is calculated. Obtained, a speed difference detection unit that outputs a speed difference signal, a frequency setting unit that sets a frequency increase / decrease amount based on the speed difference signal, a pulse width setting unit that sets a pulse width corresponding to the target speed, and A sine wave oscillating unit that sine wave oscillates at a frequency corresponding to the target speed, and finely adjusts the frequency of the generated sine wave based on the frequency increase / decrease amount set by the frequency setting unit. A PWM section that generates a reference wave based on the pulse width set by the pulse width setting section, and generates a PWM signal based on the reference wave and the sine wave output from the sine wave oscillating section; A pulse generator for generating a plurality of pulse signals having different phases based on the PWM signal generated by the PWM unit, and for driving the vibration wave motor based on the plurality of pulse signals output from the pulse generator And a step-up unit that generates the drive signal and output the drive signal to the vibration wave motor.

According to the third aspect of the present invention, the drive control of the vibration wave motor for obtaining a driving force by exciting the electro-mechanical energy conversion element by applying a frequency signal to the electro-mechanical energy conversion element. In the apparatus, an encoder that detects an operating speed of the vibration wave motor, and a speed difference detection unit that obtains a speed difference between an operation speed detected by the encoder and a target speed of the vibration wave motor, and outputs a speed difference signal. A frequency setting unit that sets a frequency increase / decrease amount based on the speed difference signal, a pulse width setting unit that sets a pulse width corresponding to the target speed, and a sine wave oscillation at a frequency corresponding to the target speed. , The amplitude of the generated sine wave is determined based on the pulse width set by the pulse width setting unit, and the frequency of the generated sine wave is determined by the frequency setting unit. P a sine wave oscillator for fine adjustment on the basis of a constant frequency increment or decrement, generates a predetermined reference wave, based on the sine wave output from the from the reference wave sine wave oscillator section
A PWM unit for generating a WM signal, a pulse generator for generating a plurality of pulse signals having different phases based on the PWM signal generated by the PWM unit, and a plurality of pulse signals output from the pulse generator. Based on the above, there is provided a vibration wave motor drive control device including a booster that generates a drive signal for driving the vibration wave motor and outputs the drive signal to the vibration wave motor.

According to the fifth aspect of the invention, the drive control of the vibration wave motor, in which a frequency signal is applied to the electro-mechanical energy conversion element to excite the electro-mechanical energy conversion element to obtain a driving force. In the apparatus, an encoder that detects an operating speed of the vibration wave motor, and a speed difference detection unit that obtains a speed difference between an operation speed detected by the encoder and a target speed of the vibration wave motor, and outputs a speed difference signal. A frequency setting unit that sets a frequency increase / decrease amount based on the speed difference signal, a pulse width setting unit that sets a pulse width corresponding to the target speed, and a sine wave oscillation at a frequency corresponding to the target speed. , A sine wave oscillator that finely adjusts the frequency of the generated sine wave based on the frequency increase / decrease amount set by the frequency setting unit, and a frequency applied to the vibration wave motor. A voltage detection unit that detects the voltage waveform of the signal, compares the sine wave output from the sine wave oscillator and the voltage waveform detected by the voltage detection unit, and determines the difference between the sine wave and the voltage waveform. On the basis of the comparison unit for correcting the sine wave output from the sine wave oscillating unit, the level of the reference wave is set based on the pulse width set by the pulse width setting unit, and the reference wave and the comparison unit are set. A PWM unit that generates a PWM signal based on the corrected sine wave output from the PW;
A pulse generator for generating a plurality of pulse signals having different phases based on the PWM signal generated in the M section, and for driving the vibration wave motor based on the plurality of pulse signals output from the pulse generator. And a step-up unit that generates the drive signal and output the drive signal to the vibration wave motor.

[0030]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) FIG. 2 is a diagram showing the overall construction of a color image forming apparatus incorporating a vibration wave motor drive controller according to the present invention.

First, the structure of the reader section will be described.

In FIG. 2, 101 is a charge coupled device (Ch
arge Coupled Device, hereinafter referred to as "CCD"), 31
1 is a substrate on which the CCD 101 is mounted, 312 is a printer processing unit, 301 is a document table glass, 302 is a document feeder, 303 and 304 are light sources for illuminating documents, 305
Reference numerals 306 and 306 denote reflectors for converging light from the light sources 303 and 304 on the original document, 307 to 309 are mirrors, 310 is a lens for converging reflected light or projection light from the original document on the CCD 101, and 314 is light sources 303 and 304. Reflective umbrella 305, 30
6, a carriage 315 for accommodating the mirror 6 and the mirror 307, a carriage 315 for accommodating the mirrors 308, 309, and an interface 313 with an intelligent processing unit (IPU) for realizing an interface with an analog / digital image.

The carriage 314 is moved at a speed V and the carriage 315 is moved at a speed V / 2 in a direction perpendicular to the electrical scanning (main scanning) direction of the CCD 101, thereby scanning the entire surface of the document (sub-scanning). ) Do.

A document on the platen glass 301 is a light source 30.
The light from 3,304 is reflected, and the reflected light is reflected by the CCD 10.
It is guided to 1 and converted into an electric signal. Then, the electric signal (analog image signal) is input to the printer processing unit 312 and converted into a digital signal. The converted digital signal is subjected to a predetermined process and then sent to the printer unit to be used for image formation.

Next, the configuration of the printer section will be described.

In FIG. 2, 317 is M (magenta color).
The image forming unit 318 is a C (cyan) image forming unit, 31
9 is a Y (yellow) image forming unit, 320 is K (black)
The image forming unit. Since the respective configurations are the same, only the M image forming unit 317 will be described, and description of the other image forming units will be omitted.

In the M image forming unit 317, 342 is a photosensitive drum, and a latent image is formed on the surface thereof by the light from the LED array 210. Reference numeral 321 denotes a primary charger that charges the surface of the photosensitive drum 342 to a predetermined potential to prepare for latent image formation. A developing unit 322 develops the latent image on the photosensitive drum 342 to form a toner image. The developing device 322 includes a sleeve 361 for applying a developing bias for developing. 323
Is a transfer charger, which discharges from the back surface of the transfer belt 333 to transfer the toner image on the photosensitive drum 342 to a recording paper or the like on the transfer belt 333. In this embodiment, since the transfer efficiency is good, the conventionally used cleaner portion is not arranged (the cleaner portion may be attached).

Next, a procedure for forming an image on a recording paper or the like will be described.

The recording sheets and the like stored in the cassettes 340 and 341 are taken out one by one by the pickup rollers 339 and 338, and supplied onto the transfer belt 333 by the sheet feeding rollers 336 and 337. The supplied recording paper is charged by the adsorption charger 346. Transfer belt rollers 348a to 348d drive the transfer belt 333, and the transfer belt roller 348a forms a pair with the adsorption charger 346 to charge the recording paper or the like and cause the transfer belt 333 to adsorb the recording paper or the like. . Reference numeral 347 denotes a paper edge sensor, which is used for the transfer belt 3
The leading edge of the recording paper on 33 is detected. The detection signal of the paper leading edge sensor 347 is sent from the printer unit to the reader unit, and is used as a sub-scanning synchronization signal when sending a video signal from the reader unit to the printer unit.

After that, the recording paper or the like is conveyed by the transfer belt 333, and is transferred to the MC in the image forming units 317 to 320.
A toner image is formed on the surface in the order of YK. The recording paper or the like that has passed through the K image forming unit 320 at the end is easily removed from the transfer belt 333 in order to facilitate the separation.
After the charge is removed by, the transfer belt 333 is separated. Three
Reference numeral 50 is a peeling charger, and recording paper is a transfer belt 333.
It is intended to prevent the image distortion caused by the peeling discharge when separating from. The separated recording paper or the like is charged by pre-fixing chargers 352 and 353 in order to compensate for the toner suction force and prevent image disturbance, and then the toner image is thermally fixed by the fixing device 334, and the discharge tray is discharged. The sheet is ejected to 335.

A vibration wave motor is used to rotate one of the photosensitive drums 342 to 345 and the transfer belt rollers 348a to 348d. A vibration wave motor generates a vibration wave on the surface of an elastic body by applying an AC signal to an electro-mechanical energy conversion element such as a piezoelectric element fixed to the elastic body, and the moving body responds to the vibration wave. It is a motor of the principle of driving a moving body by bringing into contact with. Hereinafter, a case where a vibration wave motor is connected to the photosensitive drum will be described as an example.

FIG. 1 is a block diagram showing the configuration of a vibration wave motor drive control device according to the first embodiment of the present invention. In the figure, the same components as those of the conventional vibration wave motor drive control device shown in FIG. 8 are designated by the same reference numerals, and the description thereof will be omitted.

In the first embodiment, a sine wave oscillating section 20a and a PWM section 21a are newly added. That is, the sine wave oscillating unit 20a receives the frequency increasing / decreasing manipulated variable created by the frequency setting unit 17, and the command speed from the target value commanding unit 30. The sine wave oscillating unit 20a oscillates a sine wave at a frequency according to the input command speed (target speed), finely adjusts the frequency of the sine wave according to the input frequency increasing / decreasing operation amount, and obtains the sine wave. The signal is full-wave rectified and then output to the PWM unit 21a.

Pulse width information is sent from the pulse width setting unit 11 to the PWM unit 21a, and the PWM unit 21a, as shown in FIG. 3, is a triangular wave (A) which is a reference wave based on the sent pulse width information. To generate. And with the triangular wave (A),
The sine wave signal after full-wave rectification (B) input from the sine wave oscillating unit 20a is compared, and when the level of the former is smaller than the level of the latter, the level becomes high, and when it is the opposite, the level becomes low. The PWM signal (C) is generated, and the pulse generator 12
Send to. FIG. 3 is a timing chart showing a triangular wave (A), a sine wave signal after full-wave rectification (B), and a PWM signal (C).

The pulse generator 12 has four-phase PWM pulse signals A1, A2, A3, A4, B1, B2, B3, B based on the pulse width of the PWM signal sent from the PWM section 21a.
4 is generated.

FIG. 4 shows four-phase PWM pulse signals A1 and A.
2 is a timing chart showing A2, A3, A4, B1, B2, B3 and B4.

The pulse generator 12 has PWM pulse signals A1, A2, A3, A4, B1, whose pulse widths are the pulse widths of the PWM signals sent from the PWM section 21a.
B2, B3 and B4 are generated. Then, the PWM pulse signal A1 and the PWM pulse signal A2, and the PWM pulse signal B1 and the PWM pulse signal B2 are each 180 °.
Of the PWM pulse signal A1 and PW
M pulse signal B1 and PWM pulse signals A2 and P
A phase difference of 90 ° is provided for each of the WM pulse signals B2.

Four-phase P output from the pulse generator 12
WM pulse signal A1, A2, A3, A4, B1, B2
B3 and B4 are input to the booster 13. The internal configuration of the booster 13 is the same as that in FIG.

FIG. 5 shows A-phase AC sine wave, -A phase AC sine wave, B-phase AC sine wave, and -phase output from the booster 13.
It is a timing chart which shows a B-phase AC sine wave.

A four-phase pulse signal A as described with reference to FIG.
1, A2, A3, A4, B1, B2, B3, B4 are respectively used as the gate signals of the FETs 27a to 27h (FIG. 10) of the booster 13, so that a sine wave signal as shown in FIG. It is output from 13. The phase difference between the A-phase AC sine wave output and the -A phase AC sine wave output is 180 °, and the phase difference between the B-phase AC sine wave output and the -B phase AC sine wave output is 1
A phase difference of 80 ° results in a sine wave signal having a phase difference of 90 ° between the A-phase AC sine wave output and the B-phase AC sine wave output.
Thus, the A-phase AC sine wave output, the -A phase AC sine wave output, the B-phase AC sine wave output, and the -B phase AC sine wave output are input to the vibration wave motor 14 of FIG.

The vibration wave motor 14 is driven by such an AC sine wave signal according to the principle described above.

As described above, in the present embodiment, in addition to the drive frequency as the control operation amount for controlling the rotation speed of the vibration wave motor 14, the four-phase PWM pulse signals A1 and A are used.
The pulse widths of 2, A3, A4, B1, B2, B3, B4 are used. That is, the PWM unit 21a generates a triangular wave (reference wave) based on the pulse width information output from the pulse width setting unit 11, and the pulse width of the PWM signal output from the PWM unit 21a is set to the above pulse width information. It changes based on.

Thus, in addition to the drive frequency, the four-phase P
By also using the pulse width of the WM pulse signal as the control operation amount, the rotation speed of the vibration wave motor 14 can be maintained at the target speed, and at the same time, the frequency signal applied to the vibration wave motor 14 by the PWM drive. Can be formed with a sinusoidal wave with little distortion. As a result, it is possible to generate a uniform traveling wave in the electrical-mechanical energy conversion element (piezoelectric body) of the vibration wave motor 14, and it is possible to prevent uneven wear that has occurred in the stator of the conventional vibration wave motor. It is possible to extend the life of the vibration wave motor.

(Second Embodiment) Next, a second embodiment will be described.

The configuration of the second embodiment is basically the first.
Since the configuration is the same as that of the first embodiment, the configuration of the first embodiment will be used in the description of the second embodiment, and only different components will be described.

FIG. 6 is a block diagram showing the configuration of a vibration wave motor drive control device according to the second embodiment. In the figure,
The same components as those of the vibration wave motor drive control device according to the first embodiment shown in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted.

In the second embodiment, the pulse width setting unit 1
The pulse width information output from 1 is input to the sine wave oscillating unit 20b, and the output of the sine wave oscillating unit 20b is sent to the PWM unit 21b. That is, in the sine wave oscillating unit 20b, the command speed from the target value command unit 30 (target speed)
Sine wave oscillation at a frequency according to
The frequency of the sine wave is finely adjusted by the frequency increasing / decreasing manipulated variable output from 7, and the amplitude of the sine wave is determined based on the pulse width information output from the pulse width setting unit 11. The resulting sine wave signal is full-wave rectified and then P
Output to the WM unit 21b.

The PWM section 21b generates a predetermined reference wave (triangular wave), compares the reference wave with the sine wave signal after full-wave rectification input from the sine wave oscillating section 21b, and outputs PW.
Generate an M signal.

Therefore, when the commanded speed increases,
The pulse width set by the pulse setting unit 11 widens, and the amplitude of the sine wave output from the sine wave oscillating unit 20b increases accordingly. On the contrary, if the commanded speed decreases,
The pulse width set by the pulse setting unit 11 becomes narrower, and the amplitude of the sine wave output from the sine wave oscillating unit 20b becomes smaller accordingly. As a result, as a result of the PWM pulse driving, the frequency signal applied to the vibration wave motor 14 is formed into a sinusoidal waveform with less distortion. Therefore, it is possible to generate an even traveling wave in the electric-mechanical energy conversion element (piezoelectric body) of the vibration wave motor 14, and it is possible to prevent uneven wear that has occurred in the stator of the conventional vibration wave motor. It is possible to extend the life of the vibration wave motor.

(Third Embodiment) Next, a third embodiment will be described.

The configuration of the third embodiment is basically the first.
Since the configuration is the same as that of the first embodiment, the configuration of the first embodiment will be used in the description of the third embodiment, and only different components will be described.

FIG. 7 is a block diagram showing the configuration of a vibration wave motor drive control device according to the third embodiment. In the figure,
The same components as those of the vibration wave motor drive control device according to the first embodiment shown in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted.

In the third embodiment, the voltage detecting unit 22 is provided at the output end of the boosting unit 13, and the voltage detecting unit 22 detects the frequency signal applied from the boosting unit 13 to the vibration wave motor 14, The voltage waveform is full-wave rectified and output to the comparison unit 23. The sine wave signal is input from the sine wave oscillating unit 20 a to the comparing unit 23, and the comparing unit 23 outputs the full-wave rectified voltage output from the voltage detecting unit 22 and the sine wave oscillating unit 20 a.
And the sine wave signal from the sine wave oscillating unit 20a is corrected based on the comparison result. Then, the corrected sine wave signal is output to the PWM unit 21c.
That is, the comparison unit 23 first obtains the difference between the full-wave rectified voltage output from the voltage detection unit 22 and the sine wave signal from the sine wave oscillating unit 20a, and the full wave rectified voltage is the sine wave signal. If the level is larger than the level of, the difference is subtracted from the sine wave signal from the sine wave oscillating unit 20 to correct,
On the contrary, when the voltage after full-wave rectification is smaller than the level of the sine wave signal, the difference is added to the sine wave signal from the sine wave oscillating unit 20 to correct it.

The PWM section 21c has a predetermined reference wave (triangular wave).
And the level of the reference wave (triangular wave) is determined based on the pulse width information output from the pulse width setting unit 11. Then, the corrected sine wave signal output from the comparison unit 23 is compared with the reference wave (triangular wave) to perform PWM.
Generate a signal.

As described above, by detecting the voltage of the frequency signal applied to the vibration wave motor 14 and performing the PWM pulse drive based on the detected voltage, the frequency signal applied to the vibration wave motor 14 has a sine wave with less distortion. It is formed in a wavy shape. Therefore, it is possible to generate an even traveling wave in the electric-mechanical energy conversion element (piezoelectric body) of the vibration wave motor 14, and it is possible to prevent uneven wear that has occurred in the stator of the conventional vibration wave motor. It is possible to extend the life of the vibration wave motor.

In the third embodiment, PWM pulse driving is performed by detecting the voltage applied to one piezoelectric element forming the vibration wave motor 14, but instead of this, PWM pulse driving is performed. , A voltage detection unit and a comparison unit are provided for each of a plurality of piezoelectric elements forming the vibration wave motor 14,
The PWM section 21c may individually generate the PWM signal so that the voltage applied to each piezoelectric element is a sine wave with little distortion.

[0068]

As described above in detail, according to the invention described in claim 1, the sine wave oscillating section oscillates a sine wave at a frequency corresponding to the target speed, and the frequency of the generated sine wave is changed to the target speed. Fine adjustment is performed based on the frequency increase / decrease amount set based on the speed difference between the detected speed and Further, the PWM unit generates a reference wave based on the pulse width corresponding to the target speed, and P based on the reference wave and the sine wave output from the sine wave oscillating unit.
Generate a WM signal. Then, based on this PWM signal,
A plurality of pulse signals having different phases are generated to generate a drive signal for driving the vibration wave motor.

According to the third aspect of the invention, the sine wave oscillating section oscillates a sine wave at a frequency corresponding to the target speed, and the amplitude of the generated sine wave is set to a pulse width corresponding to the target speed. The frequency of the generated sine wave is finely adjusted by the frequency increase / decrease amount set based on the speed difference between the target speed and the detected speed. The PWM unit also generates a predetermined reference wave and generates a PWM signal based on the reference wave and the sine wave output from the sine wave oscillating unit. Then, based on this PWM signal, a plurality of pulse signals having different phases are generated to generate a drive signal for driving the vibration wave motor.

Further, according to the invention of claim 5, the sine wave oscillating section oscillates a sine wave at a frequency corresponding to the target speed, and the frequency of the generated sine wave is set to the speed between the target speed and the detected speed. Fine adjustment is performed according to the frequency increase / decrease amount set based on the difference. Further, the voltage detector detects the voltage waveform of the frequency signal applied to the vibration wave motor. And
The comparing unit compares the sine wave output from the sine wave oscillating unit with the voltage waveform detected by the voltage detecting unit, and outputs the sine wave oscillating unit based on the difference between the sine wave and the voltage waveform. Correct the sine wave. Here, the PWM unit sets the level of the reference wave based on the pulse width corresponding to the target speed, and the PW is set based on the reference wave and the corrected sine wave output from the comparison unit.
Generate an M signal. Then, based on this PWM signal, a plurality of pulse signals having different phases are generated to generate a drive signal for driving the vibration wave motor.

As a result, the frequency signal applied to the vibration wave motor is formed of a sinusoidal wave with little distortion, and therefore,
The unevenness of the traveling wave is suppressed, and as a result, uneven wear that occurs in the stator of the vibration wave motor is prevented, and the life of the vibration wave motor can be extended.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a vibration wave motor drive control device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing an overall configuration of a color image forming apparatus incorporating a vibration wave motor drive control device according to the present invention.

FIG. 3 is a timing chart showing a triangular wave (A), a sine wave signal after full-wave rectification (B), and a PWM signal (C).

FIG. 4 is a timing chart showing a 4-phase PWM pulse signal.

FIG. 5 is a timing chart showing an A-phase AC sine wave, a −A phase AC sine wave, a B-phase AC sine wave, and a −B-phase AC sine wave output from the booster.

FIG. 6 is a block diagram showing a configuration of a vibration wave motor drive control device according to a second embodiment.

FIG. 7 is a block diagram showing a configuration of a vibration wave motor drive control device according to a third embodiment.

FIG. 8 is a block diagram showing a configuration of a conventional drive control device used to drive and control a vibration wave motor.

FIG. 9 is a timing chart showing a 4-phase pulse signal.

FIG. 10 is a circuit diagram showing an internal configuration of a booster unit.

[Explanation of symbols]

11 Pulse width setting section 12 pulse generator 13 Booster 14 Vibration wave motor 15 encoder 16 Speed difference detector 17 Frequency setting section 18 Target value command section 20a Sine wave oscillator 20b Sine wave oscillator 21a PWM section 21b PWM section 21c PWM section 22 Voltage detector 23 Comparison Department 30 Target value command section 31 power supply

Claims (6)

[Claims] 1. A drive control device for a vibration wave motor, wherein a frequency signal is applied to the electro-mechanical energy conversion element to excite the electro-mechanical energy conversion element to obtain a driving force, the operating speed of the vibration wave motor. An encoder that detects a speed difference between the operating speed detected by the encoder and the target speed of the vibration wave motor, and a speed difference detection unit that outputs a speed difference signal, and a frequency based on the speed difference signal. A frequency setting unit that sets an increase / decrease amount, a pulse width setting unit that sets a pulse width corresponding to the target speed, a sine wave oscillation at a frequency corresponding to the target speed, and a frequency of the generated sine wave, A sine wave oscillating unit for fine adjustment based on the frequency increase / decrease set by the frequency setting unit, and a reference wave generated based on the pulse width set by the pulse width setting unit, A PWM unit that generates a PWM signal based on a reference wave and a sine wave output from the sine wave oscillating unit, and a plurality of pulse signals having different phases based on the PWM signal generated by the PWM unit A pulse generator, and a booster that generates a drive signal for driving the vibration wave motor based on a plurality of pulse signals output from the pulse generator and outputs the drive signal to the vibration wave motor. Vibration wave motor drive control device. 2. The PWM section compares the level of a signal obtained by full-wave rectifying the sine wave output from the sine wave oscillating section with the reference wave, and outputs a PWM signal based on the result of the comparison. The vibration wave motor drive control device according to claim 1, wherein the vibration wave motor drive control device is generated. 3. A drive control device for a vibration wave motor, which applies a frequency signal to the electro-mechanical energy conversion element to excite the electro-mechanical energy conversion element to obtain a driving force, the operating speed of the vibration wave motor. An encoder that detects a speed difference between the operating speed detected by the encoder and the target speed of the vibration wave motor, and a speed difference detection unit that outputs a speed difference signal, and a frequency based on the speed difference signal. A frequency setting unit that sets an increase / decrease amount, a pulse width setting unit that sets a pulse width corresponding to the target speed, a sine wave oscillation at a frequency corresponding to the target speed, and an amplitude of the generated sine wave, It is determined based on the pulse width set by the pulse width setting unit, and the frequency of the generated sine wave is based on the frequency increase / decrease amount set by the frequency setting unit. A sine wave oscillation unit that adjusts, generates a predetermined reference wave, and generates a PWM signal based on the sine wave output from the from the reference wave sine wave oscillation unit PW
An M section, a pulse generator that generates a plurality of pulse signals having different phases based on the PWM signal generated by the PWM section, and the vibration wave based on the plurality of pulse signals output from the pulse generator. A vibration wave motor drive control device, comprising: a booster that generates a drive signal for driving the motor and outputs the drive signal to the vibration wave motor. 4. The PWM section compares the level of a signal obtained by full-wave rectifying the sine wave output from the sine wave oscillating section with the reference wave, and outputs a PWM signal based on the result of the comparison. The vibration wave motor drive control device according to claim 3, which is generated. 5. A drive control device for a vibration wave motor, which applies a frequency signal to the electro-mechanical energy conversion element to excite the electro-mechanical energy conversion element to obtain a driving force, wherein the operating speed of the vibration wave motor. An encoder that detects a speed difference between the operating speed detected by the encoder and the target speed of the vibration wave motor, and a speed difference detection unit that outputs a speed difference signal, and a frequency based on the speed difference signal. A frequency setting unit that sets an increase / decrease amount, a pulse width setting unit that sets a pulse width corresponding to the target speed, a sine wave oscillation at a frequency corresponding to the target speed, and a frequency of the generated sine wave, A sine wave oscillator that finely adjusts based on the frequency increase / decrease set by the frequency setting unit, and a voltage that detects the voltage waveform of the frequency signal applied to the vibration wave motor. The detection unit compares the sine wave output from the sine wave oscillating unit with the voltage waveform detected by the voltage detection unit, and based on the difference between the sine wave and the voltage waveform, the sine wave oscillating unit A comparator that corrects the output sine wave, and sets the level of the reference wave based on the pulse width set by the pulse width setting unit, and outputs the reference wave and the corrected sine output from the comparator. PW that generates PWM signal based on wave
An M section, a pulse generator that generates a plurality of pulse signals having different phases based on the PWM signal generated by the PWM section, and the vibration wave based on the plurality of pulse signals output from the pulse generator. A vibration wave motor drive control device, comprising: a booster that generates a drive signal for driving the motor and outputs the drive signal to the vibration wave motor. 6. The comparator outputs the sine wave output from the sine wave oscillator when the level of the sine wave output from the sine wave oscillator is smaller than the level of the voltage waveform detected by the voltage detector. The sine wave is corrected by subtracting the difference, and when the level of the sine wave output from the sine wave oscillating unit is higher than the level of the voltage waveform detected by the voltage detecting unit, the sine wave is detected. The vibration wave motor drive control device according to claim 5, wherein the sine wave output from the wave oscillating unit is corrected by adding the difference.