JP4078464B2 - Vibration actuator drive unit - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vibration actuator driving device that is driven by vibration generated by an electromechanical transducer that converts electrical energy into mechanical energy.
[0002]
[Prior art]
In Japanese Patent Laid-Open No. Hei 6-153543, in order to stably control the speed of a motor using a progressive vibration wave, the driving input waveform and sensor output waveform of the motor are considered in consideration of the driving characteristics of the vibration wave motor. By measuring the phase difference and limiting the speed by the phase difference corresponding to the predetermined rotational speed in the high rotational range of the motor, avoiding a decrease in the rotational speed near the resonance frequency of the motor, Stable speed control was performed in the high rotation range.
[0003]
Japanese Laid-Open Patent Publication No. 7-163160 discloses a vibration wave drive device that converts a power supply voltage into a drive voltage and has a drive voltage forming circuit that controls the drive voltage in accordance with the value of the power supply voltage. Even if the fluctuations occur, the driving is stabilized by supplying the driving voltage stably.
[0004]
[Problems to be solved by the invention]
However, the above-described conventional apparatus has not been sufficient with respect to the stability of the power source accompanying the increase in power consumption of the vibration actuator. For example, when sudden drive control is performed from stop or low speed to high speed, the power consumption of the vibration actuator also increases rapidly in response to a transient response, which depends on the internal resistance of the power supply and the resistance component of the power system drive circuit. There is a problem that a voltage drop occurs, exceeds the power supply capability, and the output of the power supply fluctuates, or the output stops or drops, making it difficult to perform stable drive control.
In particular, there is a possibility that the above-described problem may occur remarkably in a device that uses a battery or a battery having a low power supply capability as a power source.
[0005]
SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a vibration actuator drive device that can solve the conventional unstable drive control due to fluctuations in power supply output accompanying an increase in power consumption and can perform more stable drive control. To do.
[0006]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the invention of claim 1 is directed to a vibration actuator (1) driven by utilizing mechanical vibration of an electromechanical transducer that converts electrical energy into mechanical energy, and a power source (2 ), A drive unit (3, 4) that generates a drive signal to be applied to the electromechanical conversion element of the vibration actuator using the power supply, and a power supply detection that detects the state of the power supply while the vibration actuator is driven A drive limit signal detector for outputting a drive limit signal when the drive signal input to the electromechanical conversion element reaches a predetermined limit value, and a power source detected by the power source detector based on the state or the detection signal of the drive limiting signal detection unit, and changing the drive signal of the vibration actuator performs control Ru reduce the power consumption of the vibration actuator A vibration actuator driving device including dynamic control unit (5).
[0007]
According to a second aspect of the present invention, in the vibration actuator drive device according to the first aspect, the drive unit includes a DC / DC converter to which an output from the power source is supplied, and the power source detection unit includes the DC / DC converter. A shutdown output signal of a DC converter is monitored, and the drive control unit performs control to change the drive signal of the vibration actuator based on the shutdown output signal and to reduce power consumption of the vibration actuator. This is a vibration actuator driving device.
[0008]
According to a third aspect of the present invention, in the vibration actuator driving device according to the first or second aspect, the drive control unit changes an instruction value including a speed or an acceleration of the vibration actuator. It is a drive device.
According to a fourth aspect of the present invention, in the vibration actuator driving device according to the second aspect, the drive control unit is based on the warning signal based on the detection result of the power supply state in the power supply detection unit and the shutdown signal. The vibration actuator driving apparatus is characterized in that a warning signal is input and a warning level of the warning signal is determined.
According to a fifth aspect of the present invention, in the vibration actuator driving device according to the fourth aspect, when the drive control unit inputs a warning signal based on the detection result of the power source detection unit, the presence or absence of warning experience is determined, The vibration actuator driving apparatus is characterized in that the control for reducing the power consumption of the actuator is changed based on the determination result.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in more detail with reference to the drawings.
(First embodiment)
FIG. 1 is a block diagram showing a first embodiment of a vibration actuator driving apparatus according to the present invention. In this embodiment, a case where a progressive vibration wave motor is used as a vibration actuator will be described as an example.
The vibration wave motor 1 includes a two-phase input unit and generates a driving force by a progressive vibration wave.
The vibration wave motor 1 includes, for example, a vibration body in which a piezoelectric element (electromechanical conversion element) is attached to an elastic body, and a moving body that is in pressure contact with the vibration body, and the piezoelectric element has two phases with different phases. By applying an alternating voltage, an elliptical motion is generated on the surface of the vibrating body, and the moving body and the vibrating body move relatively by the elliptical motion and friction.
[0010]
This vibration wave motor 1 has a higher kinetic energy of the vibrating body, that is, in the vicinity of the resonance frequency, the amplitude of the elliptical motion generated in the vibrating body is increased, and the driving speed becomes higher. A frequency region where the amplitude of motion attenuates and the moving body stops is used, and the frequency of the alternating voltage applied to the vibrating body is changed in that region, and the vibrating body and the moving body are driven at a predetermined relative speed.
[0011]
FIG. 4 is a diagram showing drive frequency-rotational speed characteristics and drive frequency-current consumption characteristics when the vibration actuator (vibration wave motor) according to the present embodiment is driven with a drive signal having a constant voltage. In FIG. 4, the horizontal axis represents the drive frequency f, the vertical axis 1 represents the rotational speed N, and the vertical axis 2 represents the current value I.
In FIG. 4, the closer to the resonance frequency f0 where the kinetic energy of the vibrator becomes the maximum, that is, the elliptical motion becomes the maximum, the rotation speed increases and the power consumption also increases. That is, since it is a constant voltage drive, it has a drive characteristic that current consumption increases.
The drive characteristics change such as shifting left and right depending on the temperature and the load of the motor.
[0012]
In FIG. 1, a power source 2 is means for supplying a power output necessary for driving the vibration wave motor 1.
The motor driver (driving unit) 3 includes an oscillator for outputting an alternating voltage using a power source 2 and a phase shifter for outputting a phase different by 90 degrees, and has a phase of 90 degrees according to an instruction value from the MCU 5. This is means for outputting a shifted two-phase alternating voltage, and the output of the two-phase signals is connected to the AMPs 4a and 4b, respectively.
The AMPs (power amplifiers) 4 a and 4 b are means for amplifying power from the motor driver 3, and their outputs are applied to the two-phase input part of the vibration wave motor 1.
[0013]
The MCU (drive control unit) 5 is a means for giving an instruction value such as the rotation direction, speed, and movement amount of the vibration wave motor 1 to the motor driver 3 based on the calculation result.
The power supply monitor 6 is means for monitoring the output state of the power supply 2 and outputs a power supply abnormality signal to the MCU 5 when a malfunction such as output stop or abnormality occurs.
[0014]
When the MCU 5 receives a power supply abnormality signal from the power supply monitor 6, the MCU 5 performs calculation such as deceleration to suppress an increase in power consumption, and outputs the instruction value to the motor driver 3 to perform drive control.
[0015]
FIG. 2 is a circuit diagram showing in detail the power supply monitor 6 of FIG.
The power is supplied to a DC / DC converter 32 inside the motor driver 3 and boosted to two voltages. The transistor 35 is turned on by one output of the DC / DC converter 32, and the transistor 34 is turned on via the diode 36.
Then, one output of the DC / DC converter 32 is supplied to the regulator 33, and the output of the regulator 33 is divided by resistors 27, 28 and 29, and a reference voltage is supplied to the comparators 38 and 39, respectively.
[0016]
When the transistor 34 is turned on, the light warning signal is divided between the emitter-collector voltage of the transistor 34 and the resistors 25 and 26, and is input to the + terminal of the comparator 38 as the power supply potential state. It is obtained by comparing with the reference voltage of the negative terminal.
The severe warning signal is obtained by monitoring the shutdown output signal of the DC / DC converter 32 and inputting it to the negative terminal of the comparator 39 and comparing it with the reference voltage of the positive terminal of the comparator 39.
These obtained signals are pulled up by the resistors 30 and 31 and output to the MCU 5.
[0017]
FIG. 3 is a flowchart showing the operation of the MCU 5 during the drive control of the vibration actuator drive device according to the first embodiment.
In step 301, when a power supply abnormality warning signal is detected by the power supply monitor 6, the process proceeds to step 302, where the power supply monitor 6 determines warning levels set in advance in two stages, and otherwise proceeds to step 306. .
[0018]
In step 302, it is determined whether or not the warning level is minor using the power abnormality warning signal detected by the power source monitor 6. If the warning level is minor, the process proceeds to step 303. Otherwise, the process proceeds to step 305. move on.
In step 303, during the motor drive control, using the power supply abnormality warning signal detected by the power supply monitor 6, it is determined whether or not the warning level is determined to be severe, and there is a warning experience of a severe warning level. If YES, go to step 305, otherwise go to step 304.
[0019]
In step 304, in response to the determination that the warning level is low in step 302, the power consumption of the vibration wave motor 1 is reduced in accordance with the low warning level to prevent unstable operation. The instruction value is changed and the process proceeds to step 306.
In step 305, in response to the determination that the warning level is a severe warning level, in order to reduce the power consumption of the vibration wave motor 1 in accordance with the severe warning level and prevent unstable operation, instruction values such as speed and acceleration are used. And go to Step 306.
[0020]
In step 306, during motor drive control, warning experience is determined based on a power supply abnormality warning signal. If there is warning experience, the process proceeds to step 307, and if there is no warning experience, the process proceeds to step 308.
In step 307, even if the warning level can be avoided during the motor drive control, the instruction value is held according to the warning level to prevent recurrence until the motor drive is completed, and the process proceeds to step 308.
[0021]
In step 308, the operation amount is calculated according to the temperature, such as the rotation direction, speed, acceleration, and movement amount in the motor drive, and if there is a power supply abnormality warning, the change of the instruction value according to the warning level is calculated. The process proceeds to step 309.
In step 309, the operation amount is instructed to the motor driver 3 based on the calculation result in step 308, and the process proceeds to step 310.
[0022]
In step 310, it is determined whether or not the operation amount of the motor drive control has been reached. If not, the process returns to step 301. If it has been reached, the motor driver 3 is instructed to stop driving, and the vibration wave The drive of the motor 1 is stopped and the control is terminated.
[0023]
According to the first embodiment, by performing the processing from step 301 to step 310 in the MCU 5, when the vibration wave motor 1 is driven, an increase in power consumption is suppressed against fluctuations in the output state of the power source 2, and more Stable drive control can be realized.
[0024]
In the present invention, since the power supply monitor 6 is adopted, even when the output of the power supply 2 is changed due to the increase in power consumption of the vibration wave motor 1, the power supply monitor 6 is used to change the power supply 2 when the motor is driven. The output state is monitored, and the MCU 5 receives the detection signal from the power supply monitor 6 and calculates instruction amounts such as the driving direction, speed, acceleration, and movement amount, and uses this indication amount to vibrate the motor driver 3. Since the control is performed so as to prevent the power consumption of the wave motor 1 from increasing, stable drive control corresponding to the output state of the power source 2 can be performed.
[0025]
(Second Embodiment)
FIG. 5 is a block diagram showing a second embodiment of the vibration actuator driving device according to the present invention. In the second embodiment, parts having the same functions as those in the first embodiment are denoted by the same reference numerals at the end, and repeated descriptions are omitted as appropriate.
[0026]
In FIG. 5, 11 is a vibration wave motor, 12 is a power supply, 13 is a motor driver, 14a and 14b are AMP, 15 is an MCU, and 16 is a power supply monitor.
In the second embodiment, in order to prevent unstable drive control due to fluctuations in the output of the power supply 12 and to reliably perform control in the high speed region near the resonance frequency of the vibration wave motor 11, In addition to the configuration of the embodiment, a monitor 17 (drive limit signal detection unit) is further provided.
The monitor 17 is means for detecting a drive limit signal by comparing a drive signal monitored from one phase of the two-phase input portion of the vibration wave motor 11 with a predetermined limit value.
[0027]
FIG. 6 is a flowchart showing the operation of the MCU 15 during the drive control of the vibration actuator driving device according to the second embodiment.
In step 601, when a power supply abnormality warning signal is detected by the power supply monitor 16, the process proceeds to step 602, where a warning level set in two stages in advance is determined by the power supply monitor 16, and otherwise, the process proceeds to step 606. .
[0028]
In step 602, it is determined whether or not the warning level is mild using the power supply abnormality warning signal detected by the power supply monitor 16. If the warning level is mild, the process proceeds to step 603. Otherwise, the process proceeds to step 605. move on.
In step 603, during the motor drive control, the presence or absence of experience in which the warning level is determined to be severe is determined using the power supply abnormality warning signal detected by the power supply monitor 16, and there is a warning experience of the severe warning level. In the case of, the process proceeds to Step 605, and otherwise, the process proceeds to Step 604.
[0029]
In step 604, in response to the determination that the warning level is a mild warning level in step 602, the power consumption of the vibration wave motor 11 is reduced according to the minor warning level to prevent unstable operation. The instruction value is changed and the process proceeds to Step 606.
In step 605, in response to the determination that the warning level is a severe warning level, the power consumption of the vibration wave motor 11 is reduced in accordance with the severe warning level, and in order to prevent unstable operation, instruction values such as speed and acceleration are used. And go to Step 606.
[0030]
In step 606, when the drive restriction signal is detected by the monitor 17, a motor output warning is given, and the process proceeds to step 607 to prevent unstable operation, otherwise the process proceeds to step 608.
In step 607, in order to prevent unstable operation in the high-speed rotation region, the power consumption of the vibration wave motor 11 is reduced, instruction values such as speed and acceleration are changed, and the process proceeds to step 608.
[0031]
In step 608, during the motor drive control, warning experience is determined based on the power supply abnormality warning signal and the drive limit signal. If there is warning experience, the process proceeds to step 609. If there is no warning experience, the process proceeds to step 610.
In step 609, even if the warning state can be avoided during the motor drive control, the instruction value is held according to the warning state to prevent recurrence until the motor drive is completed, and the process proceeds to step 610.
[0032]
In step 610, the operation amount is calculated according to the temperature, such as the rotation direction, speed, acceleration, and movement amount in the motor drive, and if there is a power failure warning signal or a drive limit signal, the instruction value corresponding to the warning state is calculated. The change is calculated and the process proceeds to step 611.
In step 611, the operation amount is instructed to the motor driver 13 based on the calculation result in step 610, and the process proceeds to step 612.
[0033]
In step 612, it is determined whether or not the operation amount of the motor drive control has been reached. If not, the process returns to step 601, and if it has reached, the motor driver 13 is instructed to stop driving, and the vibration wave The drive of the motor 11 is stopped and the control is terminated.
[0034]
According to the second embodiment, when the vibration wave motor 11 is driven, in addition to the fluctuation of the output state of the power supply 12, the fluctuation of the high-speed rotation region is prevented by the drive restriction signal, thereby suppressing an increase in power consumption. Therefore, more stable drive control can be realized.
[0035]
The present invention is not limited to the embodiment described above, and various modifications and changes are possible, and these are also within the scope of the present invention.
For example, since the drive characteristics shown in FIG. 4 have the same characteristics in other types of vibration actuators, the present invention can be applied to other types of vibration actuators.
[0036]
【The invention's effect】
As described above, according to the present invention, since the state of the power supply during driving of the vibration actuator is detected and feedback control is performed based on the signal, power output due to increase in power consumption when driving the vibration actuator The effect that stable drive control can be performed is obtained even with respect to fluctuations.
Further, by providing a drive restriction, an increase in power consumption due to high-speed driving can be prevented, and more stable drive control can be performed.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a first embodiment of a vibration actuator driving device according to the present invention.
FIG. 2 is a circuit diagram illustrating a configuration example of a power supply detection unit used in the first embodiment.
FIG. 3 is a flowchart showing the operation of the MCU 5 in the first embodiment.
FIG. 4 is a diagram illustrating a driving frequency-rotational speed characteristic and a driving frequency-current consumption characteristic of the vibration wave motor according to the first embodiment.
FIG. 5 is a block diagram showing a second embodiment of the vibration actuator driving device according to the present invention.
FIG. 6 is a flowchart showing the operation of the MCU 15 in the second embodiment.
[Explanation of symbols]
1, 11 Vibration wave motor 2, 12 Power source 3, 13 Motor driver 4a, 4b, 14a, 14b Power amplifier 5, 15 MCU
6, 16 Power supply monitor 17 Monitors 21-31 Resistor 32 DC / DC converter 33 Regulator 34, 35 Transistor 36 Diode 37 Capacitor 38, 39 Comparator

Claims (5)

A vibration actuator driven using mechanical vibration of an electromechanical transducer that converts electrical energy into mechanical energy;
Power supply,
A drive unit that generates a drive signal to be applied to the electromechanical transducer of the vibration actuator using the power source;
A power source detection unit for detecting a state of the power source during driving of the vibration actuator;
A drive limit signal detection unit that outputs a drive limit signal when the drive signal input to the electromechanical transducer becomes a predetermined limit value;
Based on the detection signal of state or the drive limiting signal detection unit of the detected power supply by the power supply detection unit, the change of the drive signal of the vibration actuator, the drive control for controlling the Ru reduces the power consumption of the vibration actuator And a vibration actuator driving device. The vibration actuator driving device according to claim 1,
The drive unit includes a DC / DC converter to which an output from the power source is supplied,
The power detection unit monitors a shutdown output signal of the DC / DC converter,
The vibration actuator drive device, wherein the drive control unit performs control to change a drive signal of the vibration actuator based on the shutdown output signal and to reduce power consumption of the vibration actuator. In the vibration actuator drive device according to claim 1 or 2,
The drive control unit changes a command value including a speed or an acceleration of the vibration actuator. The vibration actuator driving device according to claim 2,
The drive control unit is a warning signal based on a detection result of the power supply state in the power supply detection unit,
A warning signal based on the shutdown signal is input to determine a warning level of the warning signal
A drive device for a vibration actuator. The vibration actuator driving device according to claim 4,
The drive control unit determines whether or not there is warning experience when a warning signal based on a detection result from the power supply detection unit is input, and changes control for reducing the power consumption of the actuator based on the determination result. A vibration actuator driving device.

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