JPH09294384A - Driving controller of vibration wave driving equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to start up a motor, etc., smoothly and to control a speed stably even when the resolution of a frequency of a driving circuit of a vibration wave driving equipment of the vibration wave motor, etc., cannot be increased so much. SOLUTION: This equipment has a controller 6 which drives a vibration wave motor 3 based on each of a plurality of driving pulses of a pulse generating means 1 that can change a pulse width and pulse intervals of each of those pulses according to the input pulse width information and frequency information and which determines the input information for the pulse generating means 1 based on the speed information of the motor 3 and then controls the driving of the motor 3. When the motor is started up, the controller 6 controls the frequency information out of the input information for the pulse generating means 1. After it finishes the control of the frequency information, it then controls the pulse width information.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a vibration wave drive device that uses resonance to generate vibration and uses the vibration energy to provide a driving force.

[0002]

2. Description of the Related Art Conventionally, a drive circuit of a vibration wave driving device such as a vibration wave motor has been constituted by an analog circuit such as a VCO (voltage controlled oscillator) or a phase shifter. However, in order to reduce the size and cost of the driving circuit, it is advantageous to configure the driving circuit with a digital circuit. As an example realized by a digital circuit, for example, a rising timing and a falling timing of a driving pulse, which is a two-phase driving signal for driving a two-phase vibration wave motor, are generated by a high-frequency reference clock to boost the voltage. 1 of the transformer which is a means
An example is that the switching timing of the switching element on the next side is performed using this reference clock.

When the drive signal is generated by the above-mentioned structure, the resolution of the oscillation frequency is limited by the frequency of the clock, and when the speed of the vibration wave motor is to be operated only by the frequency, smooth speed control is possible. It is possible that you cannot. So frequency and transformer 1
It is necessary to operate and control both the pulse widths of the switching elements on the secondary side.

In order to control both the frequency and the pulse width, in JP-A-64-85587, the frequency is swept from the higher side to the lower side (in the waveform having the resonance frequency at the peak, the frequency is higher than the resonance frequency). Since the frequency range is used as the control range, the lower the frequency, the higher the number of revolutions in this control range.) When the speed reaches the specified speed, the frequency is fixed and the drive voltage or pulse width is adjusted. It controls the speed. The speed at which the frequency is fixed here is substantially the same as the speed at which the drive voltage is controlled.

[0005]

However, in the above-mentioned conventional example, since the speed at which the frequency is fixed is substantially equal to the target speed, when the environment such as load or temperature changes after fixing the frequency, , It may be impossible to rotate at the target speed under a fixed frequency.

In order to avoid the above problem, a method of sweeping the frequency by setting the pulse width to a value smaller than the maximum speed can be considered, but since the motor output does not reach the maximum at start-up, the rising time is increased. Become slow.

A first object of the present invention according to the present application is to shorten the start-up time and provide stable speed control even when the frequency resolution of the drive circuit of the vibration wave drive device such as the vibration wave motor cannot be made very fine. It is an object of the present invention to provide a drive control device capable of controlling the frequency with a drive pulse width.

A second object of the present invention is to shorten the start-up time and provide stable speed control even when the frequency resolution of the drive circuit of a vibration wave driving device such as a vibration wave motor cannot be made very fine. It is an object of the present invention to provide a drive control device capable of controlling the frequency difference and the phase difference between the drive pulses.

[0009]

The structure for realizing the object of the first invention according to the present application is such that the pulse widths of a plurality of drive pulses to be generated and their intervals are determined according to the input pulse width information and frequency information. And a pulse generator that can be arbitrarily changed, an amplifier that amplifies a drive signal to the drive unit of the oscillatory wave drive device according to each drive pulse from the pulse generator, and a drive state of the oscillatory wave drive device. A drive state detecting means for detecting the input signal to the pulse generating means based on the detection information from the drive state detecting means, and controlling the drive of the vibration wave drive device. The control means operates the frequency information in the input information to the pulse generation means at the time of starting the vibration wave driving device, and operates the pulse width information when the operation of the frequency information is completed. Wave drive In the drive control device.

In this structure, the control means operates the input information to the pulse generating means on the basis of the speed information detected by the drive state detecting means. In these configurations, the control means ends the operation of the frequency information in the input information to the pulse generation means when the speed information detected by the drive state detection means reaches a predetermined speed.

In the above second and third configurations, the control means uses the first speed, which is a threshold value for ending the operation of the frequency information, as the target value when operating the pulse width information.
It is characterized in that the speed is higher than the speed of.

In each of the above-mentioned configurations, the control means sets the pulse width generated by the pulse generating means at the time of operating the frequency information to the pulse width at which the output of the vibration wave driving device becomes maximum. .

With the configuration for achieving the object of the second invention related to the present application, it is possible to arbitrarily change the phase difference of a plurality of generated drive pulses and the intervals thereof according to the phase difference information and the frequency information input. Pulse generating means, amplifying means for amplifying a drive signal to the drive section of the vibration wave driving device according to each drive pulse from the pulse generating means, and drive state detection for detecting the drive state of the vibration wave driving device Means and control means for determining input information to the pulse generating means on the basis of detection information from the drive state detecting means and controlling the drive of the vibration wave drive device, the control means comprising: Drive control of an oscillatory wave drive device, characterized in that frequency information is manipulated in input information to the pulse generating means when the wave drive device is activated, and phase difference information is manipulated when the operation of the frequency information is completed. On the device.

In the structure for realizing the object of the second invention, the control means operates the input information to the pulse generating means based on the speed information detected by the driving state detecting means. To do.

The above first, which realizes the object of the second invention,
In the second configuration, the control means ends the operation of the frequency information in the input information to the pulse generation means when the speed information detected by the drive state detection means reaches a predetermined speed. .

The above second aspect for achieving the object of the second invention,
In the configuration of 3, the control means sets the first speed, which is the threshold value for ending the operation of the frequency information, to be higher than the second speed, which is the target value when operating the phase difference information. Characterize.

In each of the above-mentioned configurations for achieving the object of the second invention, the control means controls the phase difference of the drive pulse generated by the pulse generation means at the time of operating the frequency information so that the output of the vibration wave drive device is maximum. It is characterized in that the phase difference is set to

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) FIG. 2 is a block diagram showing a control circuit of a first embodiment of a drive controller for an oscillatory wave drive apparatus according to the present invention.

In FIG. 2, 1 is a pulse generator,
It outputs A and B two-phase drive pulses corresponding to the input frequency data, pulse width data, and phase difference data. FIG.
Is a circuit diagram showing the internal configuration of the pulse generator 1. Reference numeral 10 is a clock generator, which generates a timing which is a reference of this circuit. 7 is a down counter and is LOAD
When the input of the terminal becomes high level, a plurality of bits of data input to the DATA terminal are loaded into the counter. When the down count data becomes 0, a high level is output from the CO terminal. FIG. 4 is a timing chart showing the state of each signal in the circuit of FIG. In the down counter 7, since the CO terminal is connected to the LOAD terminal of the down counter 7, the output of the down counter 7 is 1 when the count value becomes 0 with the frequency data as one cycle as shown in a of FIG. It becomes high level for the time corresponding to the clock.

The down counter 8 operates similarly to the down counter 7. LO of down counter 8
Since the CO output of the down counter 7 is connected to the AD input, the pulse width data is loaded for each cycle of the driving pulse, and when the pulse width data has elapsed, the CO output of the down counter 8 is changed as shown in b of FIG. The output goes high.

Reference numeral 9 is an RS flip-flop, and SET
When the input goes high, the output Q goes high, and when the RESET input goes high, the output Q goes low. Since the CO output of the down counter 7 is connected to the SET input of the RS flip-flop 9 and the CO output of the down counter 8 is connected to the RESET input, the output Q has frequency data as one cycle and is high only for the pulse width data. A pulse that produces a level is output. This is the A-phase output.

Reference numeral 11 is a down counter for determining the phase difference. Since the CO output of the down counter 7 is connected to the LOAD input of the down counter 11, the CO output becomes high level later than the down counter 7 by the phase difference data. Two phases (A phase, applied to the vibration wave motor,
Since the ideal temporal phase difference of (B phase) is 90 °, the phase difference data should be set to a value that is ¼ of the frequency data. In this case, the CO output of the down counter 11 is as shown in FIG.
It becomes like d. Hereinafter, similarly to the A phase, the CO output of the down counter 12 becomes as shown in FIG. 4E, and the Q output of the RS flip-flop 13 becomes as shown in FIG.

As a result, the output of the pulse generator 1 has two cycles of frequency data, a pulse width of the pulse width data, and a two-phase pulse with a phase difference of 90 °.

Returning to FIG. 2, reference numeral 2 is a boosting means, which uses a transformer, an LC resonance circuit, or the like. FIG. 5 shows an example of a booster circuit using a transformer.

A vibration wave motor 3 has, for example, a vibrator and a rotor that makes pressure contact with the vibrator, and the vibrator has a vibrating body and a piezoelectric element (multilayer piezoelectric element) bonded to a side surface of the vibrating body. Element or laminated piezoelectric element between the vibrating bodies
Are sandwiched and fixed. The drive signal is
Applying an AC signal with a phase difference of 90 ° with respect to the resonance frequency of the system (vibrator or vibrating body) to the two-phase electrodes of the piezoelectric element (multilayer piezoelectric element) of the vibrator. By doing so, a traveling wave is generated in the vibrating body, and the rotor (rotor) in contact with the traveling wave is rotated. 4 is an encoder, which is a vibration wave motor 3
It is attached to the output shaft of and uses optical or magnetism to output a pulse for a rotation angle. A speed detector 5 measures and outputs the frequency of the pulse output from the encoder 4. A microcomputer 6 determines various data for the pulse generator 1 based on the data obtained from the speed detector 5.

The control operation of the microcomputer 6 is shown in FIG.
It is shown in the flowchart.

When a command to start the vibration wave motor is given by an external signal or inside the microcomputer, STEP1
Is started.

In STEP 2, a predetermined initial frequency is output to the pulse generator 1. Here, a value that is always higher than the resonance frequency of the vibration wave motor 3 is selected as the initial frequency even if there is an individual difference of the vibration wave motor 3 or a change in temperature, load, or the like. This is because the frequency-speed characteristic of the vibration wave motor has a reverse slope with the resonance frequency as a boundary, and the slope is extremely steep at the frequency lower than the resonance frequency, so stable control cannot be performed. For the reason, in the region where the frequency is higher than the resonance frequency, the driving speed becomes faster as the driving frequency becomes lower, and conversely, the driving speed becomes slower as the driving frequency becomes higher.

In STEP 3, the maximum pulse width is set in the pulse generator 1 as pulse width data within a range in which the vibration wave motor 3 or the boosting means 2 is not destroyed. This is for shortening the starting time by setting the pulse width so that the vibration wave motor 3 can output the maximum torque at the time of starting.

However, if the pulse width is made unnecessarily large, the circuit elements of the boosting means 2 such as switching elements and the vibration wave motor may be destroyed, so that point must be taken into consideration when setting.

Although not specified in the flow chart, the phase difference data output to the pulse generator 1 is such that the two-phase pulse output from the pulse generator 1 has a phase difference of 90 °, that is, One quarter of the frequency data is always output.

In STEP 4, the data (v) from the speed detector 5 is input.

At STEP 5, it is determined whether the input speed (v) is larger than a preset value (v1). If not, proceed to STEP 6. Here, v1 is set to a value larger than the final target speed (v2).

In STEP 6, the drive frequency is lowered based on the difference between the input speed (v) and the set value (v1). Here, since the frequency data of the pulse generator 1 is the value of the period of the drive signal, lowering the frequency means increasing the frequency data. The processing for changing the frequency data may be performed by adding a value obtained by multiplying v1-v by a constant, or by using a table set for the value of v1-v, Or v1-v
A constant value may be added regardless of the value of. After executing STEP6, the process proceeds to STEP4 again. The above STEP4 to S
The operation of the TEP 6 is performed at regular time intervals using a timer interrupt generated by a microcomputer.

If the determination in STEP 5 is true, STEP
Proceed to 7. The frequency is fixed at this stage and is not changed later.

In STEP 7, speed data (v) is input as in STEP 4.

In STEP 8, the pulse width is controlled based on the difference between the input speed (v) and the target speed (v2). The processing for controlling the pulse width may be controlled by multiplying v2-v by a constant, or may be performed using a table. As described above, the target speed (v2) is set to a value smaller than the speed (v1) used as the reference for fixing the frequency.

At STEP 9, it is judged whether or not a stop command is issued to the vibration wave motor 3 from the outside or a microcomputer. If the stop command is not issued, the process proceeds to STEP 7 again to continue the speed control, and if the stop command is issued, the drive of the vibration wave motor is stopped.

FIG. 6 shows a velocity profile when the vibration wave motor 3 is controlled according to the first embodiment of the present invention. In the first embodiment of the present invention, the pulse width at startup is set to a value at which the maximum output is obtained from the vibration wave motor, and the frequency is fixed at a speed higher than the target speed. When the speed is controlled by manipulating the width, the pulse width is not maximized, that is, the pulse width is controlled with a margin. As a result, even when the frequency resolution is rough, such as when an output pulse is generated by a digital circuit or the like, it is not necessary to change the frequency in a steady state, so that it is possible to prevent a large speed fluctuation. That is, it is possible to achieve both a short start-up time and steady-state speed stability.

In the present embodiment, the driving direction of the vibration wave motor is described only for one direction, but when driving in the opposite direction, the drive pulse input to the A phase and the B phase of the vibration wave motor 3 is switched. It may be replaced depending on the situation.

Although the frequency and the pulse width are controlled by the software of the microcomputer in this embodiment, the same effect can be obtained by using a logic circuit or a DSP instead of the microcomputer. Needless to say.

(Second Embodiment) Next, a second embodiment of the present invention will be described.
An embodiment will be described.

The circuit configuration of the control device of the vibration wave driving device according to the second embodiment is exactly the same as that of the first embodiment shown in the figure, and therefore its explanation is omitted. The difference between the first embodiment and the second embodiment lies in the processing in the microcomputer 6. In the first embodiment, speed control during steady drive is performed by operating the pulse width, but in the second embodiment speed control during steady drive is performed by operating the phase difference of the drive signals. . The operation of the control device for the vibration wave driving device according to the second embodiment of the present invention will be described in detail below with reference to the flowchart of FIG. 7.

When an instruction to start the vibration wave motor is given by an external signal or inside the microcomputer, STEP1
Driving of 0 is started.

In STEP 11, a predetermined initial frequency is output to the pulse generator 1. Here, as with the first embodiment, the initial frequency is selected to be a value that is always higher than the resonance frequency of the vibration wave motor 3 even if there are individual differences of the vibration wave motor 3 and changes in temperature, load, and the like. To do.

In STEP 12, in order to shorten the start-up time, 90 °, which is the phase difference that allows the vibration wave motor 3 to produce the maximum torque, is set for the pulse generator 1. Specifically, the pulse width data is set to 1/4 of the frequency data.
Although not specified in the flowchart, the pulse width data output to the pulse generator 1 is set to the maximum pulse width within the range where the vibration wave motor is not destroyed.

In STEP 13, the data (v) from the speed detector 5 is input.

At STEP 14, it is judged whether the input speed (v) is larger than a preset value (v1). If not, proceed to STEP 15. Here, v1 is set to a value larger than the final target speed (v2).

In STEP 15, the drive frequency is lowered based on the difference between the input speed (v) and the set value (v1). Since the frequency data of the pulse generator 1 is the value of the cycle of the drive signal, lowering the frequency means increasing the frequency data. The process for changing the frequency data is the same as in the first embodiment, v1-v
May be added with a constant, or v1-
You may add using the table set with respect to the value of v, or may add a fixed value regardless of the value of v1-v. After executing STEP15, the process proceeds to STEP13 again so that the phase difference becomes 90 ° according to the changed frequency. The operations in STEPS 12 to 15 are performed at regular time intervals using a timer interrupt generated by a microcomputer.

If the determination in STEP 14 is true, STE
Go to P16. The frequency is fixed at this stage and is not changed later.

In STEP 16, the speed data (v) is input as in STEP 13.

In STEP 17, the phase difference is controlled based on the difference between the input speed (v) and the target speed (v2).
The process for controlling the phase difference may be controlled by multiplying v2-v by a constant, or a table may be used. As described above, the target speed (v2) is set to a value smaller than the speed (v1) used as the reference for fixing the frequency.
The relationship between the phase difference and the speed has a characteristic that the speed has a peak at 90 °, but the size of the slope does not change whether it is larger or smaller than 90 °, so which side is used with 90 ° as the limit. Good.

At STEP 18, it is judged whether or not a stop command is issued to the vibration wave motor 3 from the outside or a microcomputer. If the stop command is not issued, the process proceeds to STEP 16 again to continue the speed control, and if the stop command is issued, the drive of the vibration wave motor is stopped.

When the vibration wave motor 3 is controlled according to the second embodiment of the present invention, the velocity profile shown in FIG. 6 is obtained as in the first embodiment.

In the second embodiment of the present invention, the phase difference between the two-phase drive signals at the time of starting is set to a value at which the maximum output can be obtained from the vibration wave motor, and the drive frequency at the time of starting is higher than the target speed. Since the speed is fixed at a high speed, the phase difference is 9
It does not become 0 °, that is, the phase difference is controlled with a margin. As a result, it is possible to prevent an increase in speed fluctuation because it is not necessary to change the frequency in a steady state even when the frequency resolution is rough, as in the case where an output pulse is generated by a digital circuit or the like. That is, it is possible to achieve both a short start-up time and steady-state speed stability.

In the present embodiment, the driving direction of the vibration wave motor is described only in one direction, but when driving in the opposite direction, the drive pulse input to the A phase and the B phase of the vibration wave motor 3 is switched. It may be replaced depending on the situation.

Although the frequency and the phase difference are controlled by the software of the microcomputer in the present embodiment, the same effect can be obtained by using a logic circuit or a DSP instead of the microcomputer. Needless to say.

[0058]

According to the inventions according to claims 1, 2, 3, 4, and 5, the frequency is manipulated at the time of starting the vibration wave driving device such as the vibration wave motor, and when the frequency becomes a value higher than the target speed, Is fixed, and after that, by controlling the target speed by manipulating the pulse width, it is possible to achieve both short startup time and steady-state speed stability even with pulse generation means having a coarse frequency resolution. .

According to the sixth, seventh, eighth, ninth and tenth aspects of the invention, the frequency is manipulated when the vibration drive wave device such as the vibration wave motor is started, and the frequency is fixed when it reaches a certain value higher than the target speed. However, after that, by controlling the target speed by operating the phase difference, it is possible to achieve both a short starting time and steady-state speed stability even with a pulse generating means having a coarse frequency resolution.

[Brief description of drawings]

FIG. 1 is a flowchart showing a control operation according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a control circuit configuration according to first and second embodiments of the present invention.

FIG. 3 is a circuit diagram of a pulse generator according to the first and second embodiments of the present invention.

FIG. 4 is a time chart showing each signal in the pulse generator according to the first and second embodiments of the invention.

FIG. 5 is a circuit diagram of a booster unit according to the first and second embodiments of the present invention.

FIG. 6 is a graph showing the relationship between speed and time according to the first and second embodiments of the present invention.

FIG. 7 is a flowchart showing a control operation according to the second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 pulse generator 2 boosting means 3 vibration wave motor 4 encoder 5 speed detector 6 microcomputer 7, 8, 11, 12 down counter 10 clock 9, 13 RS flip-flop

Claims (10)

[Claims] 1. A pulse generator that can arbitrarily change the pulse widths of a plurality of generated drive pulses and their intervals according to the input pulse width information and frequency information, and each drive from the pulse generator. An amplifying unit that amplifies a drive signal to the driving unit of the vibration wave driving device according to the pulse, a driving state detecting unit that detects a driving state of the vibration wave driving unit, and a detection information from the driving state detecting unit. Control means for determining the input information to the pulse generating means and controlling the drive of the vibration wave driving device, the control means having input information to the pulse generating means when the vibration wave driving device is activated. A drive control device for a vibration wave driving device, characterized in that frequency information is operated in the above, and when the operation of the frequency information is completed, the operation of pulse width information is performed. 2. The vibration wave drive apparatus according to claim 1, wherein the control means operates the input information to the pulse generating means based on the speed information detected by the drive state detecting means. Drive controller. 3. The control means according to claim 1, wherein when the speed information detected by the drive state detecting means reaches a predetermined speed, the control means ends the operation of the frequency information in the input information to the pulse generating means. An oscillating wave drive device characterized in that. 4. The control means according to claim 2 or 3, wherein the first speed, which is a threshold value for ending the operation of the frequency information,
A drive control device for a vibration wave drive device, wherein the drive speed is set higher than a second speed which is a target value when operating the pulse width information. 5. The control means according to claim 1, 2, 3 or 4, wherein the pulse width generated by the pulse generating means at the time of operating the frequency information is the pulse width at which the output of the vibration wave driving device becomes maximum. A drive control device for a vibration wave drive device, characterized by being set. 6. A pulse generating means capable of arbitrarily changing a phase difference of a plurality of drive pulses to be generated and an interval thereof according to inputted phase difference information and frequency information, and each drive from the pulse generating means. An amplifying unit that amplifies a drive signal to the driving unit of the vibration wave driving device according to the pulse, a driving state detecting unit that detects a driving state of the vibration wave driving unit, and a detection information from the driving state detecting unit. Control means for determining the input information to the pulse generating means and controlling the drive of the vibration wave driving device, the control means having input information to the pulse generating means when the vibration wave driving device is activated. A drive control device for a vibration wave driving device, characterized in that frequency information is operated in the above, and phase difference information is operated when the operation of the frequency information is completed. 7. The vibration wave drive apparatus according to claim 6, wherein the control means operates the input information to the pulse generating means based on the speed information detected by the drive state detecting means. Drive controller. 8. The control means according to claim 6, wherein when the speed information detected by the drive state detecting means reaches a predetermined speed, the control means ends the operation of the frequency information in the input information to the pulse generating means. An oscillating wave drive device characterized in that. 9. The control means according to claim 7 or 8, wherein the first speed, which is a threshold value for ending the operation of the frequency information,
A drive control device for a vibration wave drive device, wherein the drive speed is set higher than a second speed which is a target value when operating the phase difference information. 10. The control means according to claim 6, 7, 8 or 9, wherein the phase difference of the drive pulse generated by the pulse generating means when the frequency information is operated is such that the output of the vibration wave drive device becomes maximum. A drive control device for a vibration wave drive device, wherein the phase difference is set.