JPH11178366A - Vibrating actuator, drive device thereof equipment using the same, and vibrating actuator device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drive device of a vibrating actuator for stably performing drive control, when the vibrating actuator is started and stopped accompanying changing speed. SOLUTION: A drive device adds a speed difference signal from a speed difference detector 51 by an adder 54 through a proportional controller 52 and an integrator 53, and settles a drive signal that is supplied to a vibrating actuator 57 according to output from the adder 54. In this case, at the start, stop, and speed change requiring a change in the control gain, the output of a speed difference from the speed detector 51 for the proportional controller 52 is retained as zero and then is changed into a next control gain.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving apparatus for a vibration type actuator which generates a vibration wave in a vibration body and relatively moves a moving body in contact with the vibration body by frictional force, a device using the vibration type actuator, and an apparatus using the vibration type actuator. The present invention relates to a vibration type actuator device.

[0002]

2. Description of the Related Art As is well known, a vibration-type actuator generates a high-frequency vibration by applying an alternating voltage to an electro-mechanical energy conversion element such as a piezoelectric element or an electrostriction element. This is a new non-electromagnetic drive type motor configured to extract the vibration energy as continuous mechanical motion.

FIG. 9 is a cross-sectional view of a conventional vibration type actuator. Reference numeral 1 denotes a ring-shaped metal elastic body made of, for example, stainless steel or phosphor bronze.
A piezoelectric element group 2 in which two driving piezoelectric elements (A-phase piezoelectric element and B-phase piezoelectric element) polarized in a plurality are formed in a ring shape.
Are concentrically adhered. Electrodes are arranged on both end faces of the piezoelectric element group 2 so as to generate a traveling wave on the surface of the slider member 3 made of resin, metal, ceramic, or the like bonded to the other end face of the elastic body 1, Polarization processing has been performed. On the surface on the slider material 3 side, a plurality of comb-shaped grooves are regularly formed in the circumferential direction to increase the motor efficiency. A vibrating body (stator) is constituted by the elastic body 1, the piezoelectric element group 2, and the slider member 3.

A flexible substrate 4 for taking out a drive signal and a signal from a sensor unit for detecting a vibration state of a motor provided on the piezoelectric element is fixed to a surface opposite to the piezoelectric element group 2. The inner peripheral portion of the elastic body 1 has a thin disk shape, and is fixed to the base member 5 on the inner peripheral side by bonding or screws. A moving body 6 is brought into pressure contact with the surface of the slider member 3 via a vibration isolating rubber 7 by a leaf spring 8 coaxially with the elastic body 1, and the inner diameter of the leaf spring 8 is tightly fitted with a shaft 10. It is fixed by a disc flange 9.

The shaft 10 is engaged with and inserted into the bearings 11 and 12 engaged with the base, and retains the pressing force by the retaining ring 13. The spacer 14 applies a preload to the bearing 11 to reduce the amount of whirling of the shaft.

FIG. 10 shows a drive circuit using a microcomputer when such a vibration type actuator is used.

The driving A-phase and B-phase signals supplied to the A-phase piezoelectric element and the B-phase piezoelectric element are
Is applied. Reference numeral 21 denotes a control circuit for driving and controlling the motor (hereinafter, referred to as a control microcomputer).

Reference numeral 22 denotes a four-phase oscillator for generating a four-phase alternating voltage, and reference numerals 23, 24, 25, and 26 denote switching elements for switching a power supply voltage with the alternating voltage from the oscillator.
Reference numerals 7 and 28 denote transformers for boosting the power supply voltage while matching the impedance with the motor. 40 is a capacitor for smoothing the voltage of the power supply, and 41 to 48 are resistance elements for controlling the drive current of the switching elements. Reference numeral 29 denotes a speed detector (for example, an encoder) for detecting the speed of the motor, and reference numeral 30 denotes a speed detection circuit for converting a signal from the speed detector 29 into a speed signal.

In the above-described circuit configuration, a drive state change command such as start-up, drive stop, speed change from low speed to high speed, etc., is commanded from a CPU (not shown), and the drive frequency and the drive signal are adjusted so as to reach the target speed. The driving vibration type actuator is controlled by adjusting the amplitude or the phase difference of the driving signal.

On the other hand, FIG. 11 is a control block diagram for performing proportional-integral control of a vibration type actuator. Reference numeral 51 denotes a speed difference detector, and pulse information obtained from a rotary encoder 58 connected to an output shaft of a vibration type actuator 57. And detects and outputs the difference between the drive speed and the speed command value. 52 is a proportional controller that gives a gain to the detection result of the speed difference detector 51, 53 is an integrator that integrates the output of the proportional controller, and 54 is an adder.

A pulse generator 55 uses the frequency of an AC voltage applied to the vibration type actuator 57 as an operation amount for controlling the speed of the vibration type actuator 57. 56 is a booster for boosting the pulse signal from the pulse generator 55.

With the above-described proportional-integral control, the speed of the vibration type actuator is controlled so as to reach the target speed with high responsiveness.

[0013]

In such a vibration type actuator driving apparatus, the control gain applied to the proportional controller 52 is such that the driving state is changed at the time of starting, stopping, and changing the speed. Is not considered.

Therefore, when the vibration type actuator is driven in the control loop of FIG. 11 at the time of starting, at the time of stopping, and when the driving state is changed such as changing the speed, the state before the change (the control gain before the change) is changed. There is a problem that the control remains unstable because the drive is performed with a control gain that cannot be matched at the start of the drive after the change.

An object of a first invention according to the present application is to provide a driving apparatus for a vibration-type actuator which can stably perform drive control accompanying a change in a driving state such as starting, stopping, and changing the speed of the vibration-type actuator. What you want to do.

An object of a second invention according to the present application is to stably perform drive control accompanying a change in a drive state, such as starting, stopping, and changing a speed of a driven body driven by a vibration type actuator. It is an object to provide a device using a vibration type actuator.

A third aspect of the present invention is to provide a vibration-type actuating device that can stably perform drive control in response to a change in driving state, such as starting, stopping, and changing the speed of the vibration-type actuator. Things.

[0018]

According to a first aspect of the present invention, an alternating signal to be supplied to an electromechanical energy conversion element of a vibration type actuator is adjusted according to an output of a control means. In the driving device for a vibration-type actuator, the control means controls the operation amount of the control parameter of the vibration-type actuator and, when changing the control gain of the vibration-type actuator, after holding the operation amount of the control parameter at a constant value, The control gain is changed.

The control means outputs a signal for setting the difference between the command value and the drive detection value to zero, thereby maintaining the operation amount of the control parameter at a constant value.

The manipulated variable of the control parameter is a frequency, a voltage, or a phase difference between voltages applied to a plurality of driving electro-mechanical energy conversion elements.

The manipulated variable of the control parameter is a value corresponding to the speed difference between the speed command value and the detected speed.

The control means includes a speed difference detecting portion for calculating a speed difference, a proportional control portion for giving a control gain to the calculation result of the speed difference detecting portion, and an integrated value of the proportional control portion. And an adding unit for adding the output of the proportional control unit and the integrated value of the integrating unit.

The control means is constituted by a digital circuit.

The speed difference detecting section of the control means outputs a zero speed difference signal by setting the output of a register for outputting the value of a counter for counting the speed difference to be held to zero.

The control means holds the operation amount of the control parameter at a constant value by setting the speed difference signal to zero and holding the integral value at a certain value.

The time when the control gain is changed is when the vibration type actuator is started, stopped, and when the speed is changed.

A plurality of the vibration type actuators are provided, and drive control is performed for each of the plurality of vibration type actuators.

According to a second aspect of the present invention, there is provided a device using a vibration type actuator for realizing the object of the second invention, comprising one or more of the vibration type actuator driving devices according to any one of the above. One or a plurality of driven bodies are driven using one or a plurality of vibration type actuators as a drive source.

A vibration-type actuator device for realizing the object of the third invention according to the present application is a vibration-type actuator device that adjusts an alternating signal supplied to an electro-mechanical energy conversion element of a vibration-type actuator in accordance with an output of a control means. In the actuator device, a proportional control unit that sets a predetermined gain for information corresponding to a difference between an output signal from a driving state detecting unit that outputs a signal indicating a driving state of the vibration type actuator device and a reference value; An integrating unit for integrating information according to the difference via the proportional control unit is provided in the control unit, and the alternating signal is controlled according to an output of the integrating unit. Holds the output of the integrator in the output state before the gain change, and outputs the output state of the integrator according to the information according to the difference via the proportional controller after the gain is changed. It is obtained by change.

[0030]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIGS. 1 and 2
Shows a first embodiment of the present invention.

In this embodiment, the control system in the driving device for the vibration type actuator is controlled by a microcomputer. FIG. 1 is a block diagram of the driving device for the vibration type actuator, and FIG. It is a flowchart shown. It is needless to say that the control system in the driving device may be constituted by a digital circuit.

FIG. 1 is a block diagram of a driving device for controlling a vibration-type actuator according to a first embodiment of the present invention.

In FIG. 1, reference numeral 51 denotes a speed difference detector which detects a difference between a drive speed and a speed command value based on pulse information obtained from a rotary encoder 58 connected to an output shaft of a vibration type actuator 57. And output.

The speed difference detector 51 outputs a calculation result for the speed control that changes every moment. In this embodiment, however, the calculation result for the speed control that changes every moment is output directly to the proportional controller. The switch 59 performs two kinds of switching, that is, the case where the signal is output to the controller 52 and the case where an external signal of zero is supplied to the proportional controller 52.

Reference numeral 52 denotes a proportional controller for giving a certain gain to the detection result of the speed difference detector 51, 53 denotes an integrator for integrating the output of the proportional controller, and 54 denotes an adder. A pulse generator 55 uses the frequency of an AC voltage applied to the vibration type actuator 57 as an operation amount for controlling the speed of the vibration type actuator 57. 56 is a pulse generator 5
5 is a boosting means for boosting the pulse signal from 5.

The operation of the above driving device will be described below with reference to the flowchart shown in FIG.

(# 01): At the time of activation, a certain control gain is set to a certain value, and the vibration type actuator is activated.

(# 02): Target speed (first target speed)
It is determined whether the target speed has been reached.
Proceed to 3). Here, the gain up to the first target speed is set to a sufficiently smaller gain than the steady speed.

(# 03): The switch 59 is switched so that a zero signal is input to the proportional controller 52. That is, the input to the proportional controller 52 is set to a 0 signal, and a state is created in which the output from the speed difference detector 51 becomes zero, and the vibration type actuator is driven while maintaining the speed at that time.

(# 04): A steady speed is set.

(# 05): Switching (setting) to a control gain in which the vibration type actuator moves stably at a constant speed. A plurality of control gains may be prepared in accordance with the speed and the like, and may be appropriately selected and switched, or may be set from a characteristic diagram or the like.

(# 06): The switch 59 is connected to the speed difference detector 5
Switching is performed so that the signal from 1 is input to the proportional controller 52, and a steady driving state is established.

As a result, the drive of the vibration type actuator is controlled with the control gain corresponding to the steady speed.

(# 07): It is determined whether to change the control gain. That is, it is determined whether or not there is a command to change the speed, and if there is a command to change the speed, for example, from a low steady speed to a high steady speed, (# 03)
Then, the same operation is performed to drive at a new steady speed.

If the speed is not changed in (# 07), it is determined whether or not to stop in (# 08). The drive control of the vibration type actuator is performed so as to maintain the steady speed.

When a stop command is received in (# 08),
In (# 9), the switch 59 is switched so that a zero signal is input to the proportional controller 52. That is, assuming that the input to the proportional controller 52 is 0 signal, the speed difference detector 5
The output from 1 creates a state where the speed difference is zero, and the vibration type actuator is driven while maintaining the speed at that time.

(# 10): A target speed setting for stopping is set. Since the vibration type actuator generates a driving force by using the frictional force between the vibrating body and the moving body, when the driving voltage is suddenly stopped by cutting off the driving voltage or the like, the elastic body constituting the vibrating body is generated. Since the slider material (friction material) formed on the driving surface may be damaged, it is necessary to decelerate gradually to some extent, and it is necessary to gradually decelerate when synchronization with another driven body is required. There is.

(# 11): Set to the control gain at the time of deceleration of the vibration type actuator.

(# 12): The switch 59 is connected to the speed difference detector 5
The signal is switched so that the signal from 1 is input to the proportional controller 52, the speed is set to the deceleration drive, and the operation is stopped (# 13).

Thus, the drive of the vibration type actuator is controlled with a control gain suitable for the speed for deceleration. That is, when the control gain is set to an appropriate value,
Even in the deceleration state for stopping, a signal with a speed difference of 0 is input to the proportional controller 52 from the switch 59, so that the speed control with a new control gain starts from the driving state at a constant speed. And can be stopped by stable drive control.

In this embodiment, one vibration type actuator is targeted. However, as in a color image forming apparatus, a transfer material such as recording paper is transported from a paper feed cassette to a fixing device in the middle of a transport path. In addition, photosensitive drums as image carriers of four colors (yellow, cyan, magenta, and black) are arranged at predetermined intervals, and a driving source for the photosensitive drums and a transport for transporting the transfer material are provided. Vibration type actuators may be used as the driving sources of the means, and a control block diagram in this case is shown in FIG.
In this control block diagram, the driving device of FIG. 1 is provided for each vibration type actuator, and each vibration type actuator can be driven independently. In this case, when a plurality of vibration-type actuators are driven in conjunction with each other, when changing the control gain, the control gain is changed to the non-control state first, the control gain is changed for all the vibration-type actuators, and then the control state is changed. By doing so, all the vibration type actuators can be driven in the same manner.

(Second Embodiment) FIG. 3 is a control block diagram for controlling a vibration-type actuator according to a second embodiment.

In the first embodiment, the input to the proportional controller 52 is switched by the switch 59, but in the present embodiment, the speed difference is detected by inputting a 0 signal to the speed difference detector 51 '. The configuration is such that the output of the detector 51 'can be set to zero speed difference.

FIG. 4 shows a circuit example of a speed difference detector 51 'which can make the output in the control block zero in the second embodiment.

As shown in FIG. 4, the speed difference detector is formed by a synchronous logic circuit, and 61 and 62 are D flip-flops. When the D input of the D flip-flop 62 is at a high level and the Q output is at a low level, it is detected as a rising edge of an input pulse from the encoder. At this time, the output from the AND 64 is at the high level for one clock period.

In the 16-bit down counter 65, AN
When the output of D64 is at the high level, that is, one clock cycle after the rising edge of the encoder, the target speed data is loaded. Otherwise, the down-counting is performed. The target speed data sets the count number when one cycle of the pulse of the encoder when operating at the target speed is counted by the clock. The target speed data v is obtained by the following equation.

V = fc / (N × Ep) -1 where fc is the clock frequency [Hz], N is the target rotation speed [1 / s], and Ep is the number of encoder output pulses per rotation [P / R]. For example, in the case of an encoder that outputs a clock frequency of 10 [MHz] at a target rotation speed of 1 [1 / s] and 2,000 pulses per motor rotation, the target speed data is 49.
It will be 99.

The value of the counter 65 is written to the 16-bit register 66 one clock cycle after the edge of the encoder is detected. At the moment data is written to the register 66, the target speed has not yet been loaded into the counter 65, and the count value until immediately before the encoder edge is detected is written. Register 6
The output (bar) Q of 6 outputs inverted data of the stored value.

By the operation as described above, the time from the rising edge of the encoder to the next rising edge is counted, and the value obtained by subtracting the target speed data minus 1, ie, Te × fc-v−1, is output from the register 66. Will be.

Here, v is the target speed data, Te is the cycle [sec] of the pulse output from the encoder, and fc is the clock frequency [Hz].

The speed difference data detected in the steady state as described above is input to the proportional controller 51.

Here, when a low level signal is input to the clear input of the register 66, the output from the register 66 becomes zero and is input to the proportional controller 52. In this manner, zero can be input to the proportional controller 52.

Therefore, when the control gain is changed, the output of the speed difference detector 51 'is set to zero (speed difference zero) as shown in FIGS. 3 and 4, and the control gain is switched to the next control gain to return to the steady state. It is possible to drive the motor while maintaining a stable state by changing in such a manner.

(Third Embodiment) FIG. 5 is a control block diagram for controlling a vibration-type actuator according to a third embodiment.

In the second embodiment, only the input to the proportional controller 52 can be made zero, but in the present embodiment, the integration result of the integrator 53 'is held at a certain value. It has become.

The control algorithm is the same as the flowchart of the first embodiment shown in FIG. 2, and the 0 signal for setting the output of the speed difference detector 51 'to zero is integrated into the integrator 53'.
And the integration result can be held at a certain value.

FIG. 6 shows an integrator 5 capable of holding an output in a control block at a certain value in the third embodiment.
A circuit example of 3 'is shown.

In FIG. 6, reference numeral 67 denotes an 8-bit down counter. When the data of the down counter 67 becomes 0, the carry output C goes high. At this time, the integration time constant data is loaded, and then the down count is performed. With the above operation, the down counter 67 constitutes a ring counter whose cycle is the integration time constant data. Output C
Outputs a signal which becomes high level only for one cycle of the clock once in one cycle of the ring counter.

Reference numeral 68 denotes a 16-bit adder. The adder 68 adds 16-bit input A and input B data and outputs the added data from an output S. The output data becomes the data input of the 16-bit register 69.

In the register 69, data is loaded at the timing of the integration time constant output from the down counter. As a result, integrated data corresponding to the integration time constant is output from the Q output of the register 6918.

In this embodiment, an enable terminal for holding the contents of the register 68 is provided, and when a low-level signal, which is a 0 signal, is input to the enable terminal, the output from the register 69 is held as it is. It will be in the state that was done.

In the first embodiment, the input to the proportional controller 52 is zero (the speed difference is zero).
The output from 3 may become unstable depending on the timing of changing the control gain, and if control is continued in that state, the operation may become unstable and the speed of the motor may not be controlled. On the other hand, in this embodiment, as shown in FIGS.
By inputting (low level), the value of the integrator 53 can be held at a certain value, and unstable operation does not occur even if the control gain is changed.

(Fourth Embodiment) FIG. 7 shows a fourth embodiment of the present invention.
1 is a schematic view of a paper feeder using a vibration type actuator according to an embodiment.

Reference numeral 71 denotes a roller for feeding paper, and a bearing 72 having an appropriate preload applied to the end opposite to the side where the motor is connected.
Has been arranged. A pulse plate 73 for detecting the rotation speed and rotation angle of the motor, an optical detection element 74, and a detection element mounting case 75 are provided on the side opposite to the motor roller. Since the pulse plate 73 is directly attached to the motor shaft, the accuracy is good.

For coupling the motor and the roller, the motor shaft 10 is lightly pressed into a hole provided in the roller, and is fixed from the side with a set screw 76. By using the proposed control circuit with such a device configuration, a device with high circuit efficiency can be provided.

In this case, the above-described photosensitive drum can be driven in place of the roller.

[0077]

As described above, according to the first and third aspects of the present invention, when the control gain is changed, the operation amount of the control parameter is maintained at a constant value. Control operations such as speed control of the mold activator can be performed, and stable speed control can be realized while maintaining good responsiveness in the case of starting and stopping, changing the speed, and the like.

According to the second aspect of the present invention, when one or a plurality of driven bodies are started and stopped, and the speed is changed, stable speed control can be performed while maintaining good responsiveness.

[Brief description of the drawings]

FIG. 1 is a control block diagram showing a first embodiment of the present invention.

FIG. 2 is a flowchart of a driving algorithm of FIG. 1;

FIG. 3 is a control block diagram showing a second embodiment.

FIG. 4 is a circuit diagram of a speed difference detector 51 'in FIG.

FIG. 5 is a control block diagram showing a third embodiment.

FIG. 6 is a circuit diagram of an integrator 53 'of FIG.

FIG. 7 is a cross-sectional view showing a fourth embodiment.

FIG. 8 is a block diagram illustrating a modification of the first embodiment.

FIG. 9 is a schematic configuration diagram of a conventional vibration type actuator.

FIG. 10 is a circuit block diagram of a conventional vibration type actuator driving device.

FIG. 11 is a control block diagram for controlling a conventional vibration-type actuator.

[Explanation of symbols]

 1: Elastic body 2: Piezoelectric element group 3: Slider material 4: Flexible substrate 5: Base 6: Moving body 7: Anti-vibration rubber 8: Leaf spring 9: Disk flange 10: Shaft 11, 12: Bearing 13: Retaining ring 14 : Spacer 21: Microcomputer 22: Four-phase oscillator 23, 24, 25, 26: Switching element 27, 28: Transformer 29: Current detection circuit 30: Power supply voltage control circuit 40: Capacitors 41 to 48: Resistance element 49: Resistance element 51 : Speed difference detector 52: proportional controller 53: integrator 54: adder 55: pulse generator 56: booster 57: vibration actuator 58: encoder 59: switch 61, 62: D flip-flop 65: 16 bit Down counter 66: Register 67: 8-bit down counter 68: Adder 69: Register 71: Roller 72: Bearing 73: Pulse plate 74: Optical detection element 75: Detection element mounting case 76: Set screw

Continuing on the front page (72) Kenichi Kataoka, 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Jun Ito 3-30-2, Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (13)

[Claims] 1. A driving apparatus for a vibration-type actuator, which adjusts an alternating signal to be supplied to an electro-mechanical energy conversion element of the vibration-type actuator in accordance with an output of a control means, wherein the control means includes a control parameter of the vibration-type actuator. A driving amount of the vibration-type actuator, wherein when the control amount of the vibration-type actuator is changed, the operation amount of the control parameter is held at a constant value and then changed to the next control gain. 2. The control device according to claim 1, wherein the control unit outputs a signal for setting the difference between the command value and the drive detection value to zero, thereby maintaining the operation amount of the control parameter at a constant value. 2. The driving device for a vibration-type actuator according to claim 1. 3. The operation amount of the control parameter is a frequency, a voltage, or a phase difference between voltages applied to a plurality of driving electro-mechanical energy conversion elements. Drive device for vibration type actuator. 4. The driving device according to claim 1, wherein the operation amount of the control parameter is a value corresponding to a speed difference between a speed command value and a detected speed. . 5. The control means includes: a speed difference detection hand for calculating a speed difference; a proportional control unit for giving a control gain to a calculation result of the speed difference detection hand; 5. The control device for a vibration-type actuator according to claim 4, comprising: an integration unit that integrates the integral value; and an addition unit that adds an output of the proportional control unit and an integration value of the integration unit. 6. The driving device according to claim 5, wherein said control means is constituted by a digital circuit. 7. The speed difference detecting section of the control means outputs a zero speed difference signal by setting an output of a register which outputs a value of a counter for counting a speed difference as a holdable value to zero. The driving device for a vibration-type actuator according to claim 5. 8. The control device according to claim 5, wherein the control unit holds the operation amount of the control parameter at a constant value by setting the speed difference signal to zero and holding the integral value at a certain value. Or a driving device for a vibration-type actuator according to item 6. 9. The driving apparatus for a vibration-type actuator according to claim 1, wherein the time when the control gain is changed is a time when the vibration-type actuator is started, stopped, and when a speed is changed. 10. The vibration type actuator according to claim 1, wherein a plurality of said vibration type actuators are provided, and said driving device is provided for each of said plurality of vibration type actuators. Drive. 11. A driving device for a vibration-type actuator according to claim 1, wherein the driving device comprises one or more driven devices using the one or more vibration-type actuators as a driving source. A device using a vibration-type actuator characterized by driving an actuator. 12. A vibration type actuator device for adjusting an alternating signal supplied to an electro-mechanical energy conversion element of a vibration type actuator according to an output of a control means, wherein a signal representing a driving state of the vibration type actuator device is output. A proportional control unit that sets a predetermined gain for information corresponding to a difference between an output signal from the driving state detection unit and a reference value, and an integration unit that integrates the information corresponding to the difference via the proportional control unit Provided in the control means, while controlling the alternating signal in accordance with the output of the integration unit, when changing the gain, during the change of the gain, the output of the integration unit is held in the output state before the gain change, A vibration-type actuator device wherein the output state of the integration unit is changed by information according to the difference via the proportional control unit after the gain is changed. 13. The vibration-type actuator device according to claim 12, wherein an input to the integration unit is prohibited during a period during which the gain is being changed.