JP2022069736A - Vibration type drive device - Google Patents

Abstract

To solve a problem in which, conventionally, in a vibration type drive device provided with a vibration unit in which a plurality of vibration bodies are connected, it is possible to detect the degree of deterioration of each of the vibration body, and it is difficult to grasp an appropriate maintenance time.SOLUTION: A vibration type drive device includes a control unit that outputs a command signal, a drive unit that outputs a drive signal on the basis of the command signal, and a vibration body unit in which two or more vibration bodies that vibrate on the basis of the drive signal are connected, and further includes a voltage detection unit that detects an individual applied voltage in the vibration body, and the control unit determines the driving state of the vibration body on the basis of the applied voltage.SELECTED DRAWING: Figure 1

Description

It relates to a vibration type drive device using ultrasonic vibration.

A method of detecting a defect in a vibrating body by detecting the vibration of each vibrating body in a vibrating actuator using a plurality of vibrating bodies vibrated by an electric-mechanical energy conversion element (piezoelectric element, electro-distortion element, etc.). Is known. For example, in Patent Document 1, a plurality of vibrating bodies are connected in parallel and driven by the same applied voltage, and a signal from a vibration detecting electrode provided for each vibrating body is detected to detect a defect of the vibrating body. It is shown.

In the case of a vibrating actuator in which a plurality of vibrating bodies are connected in parallel as in Patent Document 1, the degree of deterioration such as a decrease in driving efficiency of each vibrating body is detected to some extent by detecting the vibrating state of each vibrating body. Can be done. However, in the case of a vibrating actuator in which a plurality of vibrating bodies are connected in series, the applied voltage amplitude is adjusted so that the balance of the vibrating amplitude between the vibrating bodies does not change even if the vibrating body deteriorates to some extent, so that deterioration is detected. Is difficult.

In a vibrating unit in which a plurality of vibrating bodies are connected, even if one of the vibrating bodies is disconnected, the applied voltage is supplied to the other vibrating bodies and can be driven to some extent, so even if the disconnection occurs. It has the property of being able to continue driving. Especially in a series connection system, even if the pressing force and load conditions between the vibrating body and the moving body change greatly between the individual vibrating bodies, the amplitude of the applied voltage becomes large for the vibrating bodies with a large load or a distant resonance frequency. Has the property of being adjusted. Therefore, since the vibration amplitudes of the vibrating bodies are the same, it is possible to efficiently transmit the driving force to the moving body.

However, there is a possibility that the piezoelectric element accelerates the pace of deterioration due to a large difference in the applied voltage amplitude between the vibrating bodies due to a change in the load of the vibrating body or a change in the characteristics of the vibrator.

Patent No. 6651937

In a vibrating drive device equipped with a vibrating unit in which a plurality of vibrating bodies are connected, it is possible to detect the degree of deterioration of each vibrating body, and it is difficult to grasp an appropriate maintenance time.

The vibration type drive device that solves the above problems is a vibration in which a control unit that outputs a command signal, a drive unit that outputs a drive signal based on the command signal, and two or more vibrating bodies that vibrate based on the drive signal are connected. It includes a body unit and a voltage detection unit that detects an individual applied voltage in the vibrating body, and the control unit determines a driving state of the vibrating body based on the applied voltage.

According to the present invention, in a vibrating drive device having a vibrating unit in which a plurality of vibrating bodies are connected, the degree of deterioration of each vibrating body can be detected, an appropriate maintenance time can be grasped, and a peripheral mechanism can be used. It is possible to reduce the influence of.

The figure which shows the 1st example of the drive circuit of the vibration type actuator of 1st Embodiment The figure which shows the circuit example of the voltage amplitude detection means The figure which shows the 1st example of the structure of the vibration type actuator. A flowchart showing an operation example of the CPU 15 of the first embodiment. Flow chart showing the drive voltage determination operation of the first embodiment The figure which shows the 2nd example of the drive circuit of the vibration type actuator of 1st Example. The figure which shows the 3rd example of the drive circuit of the vibration type actuator of 1st Example. The figure which shows the 1st example of the drive circuit of the vibration type actuator of 2nd Example The figure which shows the circuit example of the maximum value detecting means The figure which shows the 2nd example of the drive circuit of the vibration type actuator of 2nd Example A flowchart showing an operation example of the CPU 15 of the second embodiment. The figure which shows the 3rd example of the drive circuit of the vibration type actuator of 2nd Example

An example of an embodiment for carrying out the present invention is a vibrating body in which a control unit that outputs a command signal, a drive unit that outputs a drive signal based on the command signal, and two or more vibrating bodies that vibrate based on the drive signal are connected. It has a unit. In addition, it includes a voltage detection unit that detects an individual applied voltage in the vibrating body, and the control unit is a vibration type driving device that determines the driving state of the vibrating body based on the applied voltage. Hereinafter, the details will be described with reference to the drawings.

FIG. 1 is a diagram showing a first example of a drive circuit of a vibration type actuator of the first embodiment. Reference numerals 1, 2, and 3 are vibrating bodies, and 5, 6, and 7 are transformers in which the primary side is connected in series. Reference numeral 12 is a rectangular voltage generating means for outputting a pulse signal according to a frequency command from the CPU 15 described later, and the drive voltage is transferred to the transformers 5, 6 and 7 via the waveform shaping means 11 composed of a series circuit of the inductor and the capacitor. It is applied to the series circuit of. That is, a pair of inductors connected in parallel and a parallel circuit of a transformer and a vibrating body, which can be regarded as a vibrating body, constitute the vibrating body unit in which a plurality of pairs are connected in series.

Reference numeral 13 is a resistance for measuring the current flowing on the primary side of the transformers 5, 6 and 7, and outputs a voltage substantially proportional to the vibration speed of the vibrating bodies 1, 2 and 3. The vibration displacement of the vibrating body is accurately proportional to the value obtained by integrating the vibration speed with time, but since the vibration speed amplitude is generally proportional to the vibration amplitude, the vibration speed signal amplitude is controlled in the following embodiment. This controls the vibration amplitude of the vibrating actuator 10 as the vibrating body unit.

16 and 17 and 18 are voltage amplitude detecting means for detecting the amplitude of the voltage applied to the vibrating bodies 1, 2 and 3, 14 is an A / D converter, and 15 is a known CPU. FIG. 2 shows a circuit example of the voltage amplitude detecting means. The input voltage V1 is half-wave rectified by the diode 29 and smoothed by the resistor 23 and the capacitor 24 to obtain the voltage amplitude VAMP (1). The A / D converter 14 inputs the output signals of the resistance 13 and the voltage amplitude detecting means 16, 17 and 18 to the CPU 15 which is a control unit. Based on these input information, the CPU 15 detects the amplitude of the fundamental wave of the current signal and determines the driving state of the vibration type actuator 10. Then, a frequency command and a pulse width command, which are command signals, are output to the rectangular voltage generating means 12 which is a driving unit, and the operation of the vibration type actuator 10 is controlled.

Here, an example of the vibration type actuator of this embodiment is shown. FIG. 3 is a diagram showing a structure of a vibrating actuator that rotates a cylindrical shaft by bringing three vibrating bodies into contact with the outer circumference of the cylindrical shaft. 1, 2, and 3 are vibrating bodies that vibrate in the vertical direction (direction of the arrow), and 4 is a cylindrical shaft. The vibrating bodies 1, 2, and 3 are arranged substantially evenly at intervals of 120 ° on the circumference of the cylindrical shaft 4. The cylindrical shaft 4 rotates clockwise by exciting the vibrations in the vertical direction (direction of the arrow) by vibrating the vibrating bodies 1, 2, and 3. Further, the vibrating bodies 1, 2 and 3 have a piezoelectric element bonded to the elastic body, and the vibration in the arrow direction is excited to the elastic body by applying an AC voltage to the piezoelectric element.

The cylindrical shaft corresponds to a common contact body in contact with a vibrating body unit in which two or more vibrating bodies are connected, and moves relative to the vibrating body in the direction of the resultant force generated by driving the vibrating bodies 1, 2, and 3.

Next, the operation of the CPU 15 will be described with reference to the flowcharts of FIGS. 4 and 5. First, the operation of FIG. 4 will be described. The CPU 15 first confirms the determination level HL as the drive state determination value at the time of the previous operation. When the previous determination level HL is smaller than 2, the predetermined current amplitude command Amp_C, pulse width command PW_C, and drive frequency command Frq are set as initial values. If the determination level HL is 2 or more, the pulse width command PW_C is set to 0 and the process ends.

The pulse width command PW_C and the frequency command Frq are transmitted to the rectangular voltage generating means 12, a pulse signal which is a driving signal is output from the rectangular voltage generating means 12, and a driving voltage is applied to the vibrating actuator 10 which is a vibrating body unit. .. In this way, the vibrating actuator 10 as a vibrating body unit is configured by connecting two or more vibrating bodies in a row, and the vibrating bodies are configured to be driven by a common command signal issued by the CPU 15 as a control unit. Has been done.

Next, the current amplitude is detected, and the amplitude Amp (1) of the fundamental wave component of the current is detected by filtering. Then, the drive frequency command Frq is swept in the low frequency direction at a constant rate dF until the amplitude Amp (1) of the fundamental wave exceeds the current amplitude command Amp_C. When the amplitude Amp (1) of the fundamental wave exceeds the current amplitude command Amp_C, the drive voltage determination process is performed by the drive voltage determination routine to obtain the drive voltage determination level HL as the drive state determination value. The operation of the drive voltage determination process will be described later. If the drive voltage determination level HL is larger than 2, the pulse width command PW_C is set to 0 and the process ends. If the drive voltage determination level HL is 2 or less, the operation is continued, and the drive voltage determination is repeated while controlling the drive frequency Frq until a stop command from a command means (not shown) is input. When a stop command is input from a command means (not shown), the operation is terminated with the pulse width command PW_C set to 0. Next, the drive voltage determination operation will be described with reference to FIG. In this embodiment, the applied voltage amplitudes of the vibrating bodies 1, 2 and 3 are detected in order, and the voltage amplitude evaluation which is the difference between each voltage amplitude VAMP (N) (an integer of N = 1 to 3) and a predetermined value VAMP0. The value VD (N) is obtained, and the value of VD (N) is analyzed to determine the drive voltage. In the analysis method of the voltage amplitude evaluation value VD (N), for example, the amplitude level VDL is obtained by the sum of N = 1 to 3 of VD (N), and the determination level HL corresponding to the VLD is obtained based on the predetermined conversion table HL_T. There is a way to decide. The larger the total size, the larger the determination level HL. As another example, N = 1 to 3 of the voltage amplitude evaluation value VD (N) are individually compared with a predetermined value, and how many voltage amplitude evaluation values VD (N) are larger than the predetermined value are obtained. , There is a method of setting this as the determination level HL. Further, in the above example, the applied voltage amplitude VAMP (N) is compared with a predetermined value VAMP0, but it may be compared with VAMP0 (N) determined for each vibrating body. For example, if a value obtained by multiplying the initial voltage amplitude by a certain magnification is set as VAMP (N), deterioration can be determined by the change over time of the applied voltage. Deterioration (deterioration) can also be determined by the degree of variation in the applied voltage amplitude VAMP (N). For example, the difference between the maximum value and the minimum value of VAMP (N), the standard deviation, the variance, and the like can be obtained, and the determination level HL as the drive state determination value can be determined according to the amount of these exceeding a certain value.

When the determination level HL is determined, the drive voltage determination result display LED is lit in a different color according to the determination level. When the judgment level HL = 0, it lights up in green, when HL = 1, it lights up in orange, and when HL = 2 or more, it lights up in red.

FIG. 6 is a diagram showing a second example of the drive circuit of the vibration type actuator of this embodiment. In the circuit of FIG. 1, the voltage amplitude detecting means 16, 17, and 18 detected the applied voltage amplitude of the vibrating bodies 1, 2, and 3, but in the circuit of FIG. 6, the voltage amplitude on the primary side of the transformers 5, 6, and 7. Is being detected. The amplitude of the applied voltage to the vibrating bodies 1, 2, and 3 is estimated by multiplying the outputs of the voltage amplitude detecting means 16, 17, and 18 by the winding ratios of the transformers 5, 6, and 7. Since the operation of the CPU 15 is the same as the operation described above except that this estimated value is used for the amplitude of the applied voltage, the description thereof will be omitted.

FIG. 7 is a diagram showing a third example of the drive circuit of the vibration type actuator of this embodiment. In the circuit of FIG. 1, the vibrating bodies 1, 2, and 3 were connected to the secondary side of the transformer, but in the circuit of FIG. 7, the vibrating bodies 1, 2, and 3 are connected in series, and the vibrating bodies 1, 2, and 3 are connected. Inductors 20, 21, and 22 are connected in parallel to each of the vibration type actuators 28. Then, the output signal of the rectangular voltage generating means 12 is applied to the series circuit of the vibrating bodies 1, 2, and 3 via the waveform shaping means 11. Voltage amplitude detecting means 16, 17, and 18 are connected to the vibrating bodies 1, 2, and 3, respectively, and the voltage applied to each vibrating body is measured via the A / D converter 14 in the same manner as in the first and second circuits. The amplitude is input to the CPU 15. Since the operation of the CPU 15 and the configuration and operation of other circuits are the same as those described above, the description thereof will be omitted.

Further, in the above example, the drive voltage of the vibration type actuator is one phase, but the same applies to the vibration type actuator driven by the drive voltage of a plurality of phases. There is a method of obtaining the determination level HL of the voltage amplitude for each phase, and a method of obtaining the determination level HL of the voltage amplitudes of all the phases at once.

Further, in this embodiment, three vibrating bodies are connected in series, but the same as the above description can be obtained by providing a voltage amplitude detecting means for detecting the amplitude of the applied voltage to each vibrating body even if two or three or more vibrating bodies are connected in series. Is possible.

FIG. 8 is a diagram showing a first example of the drive circuit of the vibration type actuator of the second embodiment. In the first embodiment, the outputs of the voltage amplitude detecting means 16, 17, and 18 are input to the CPU 15 by the A / D converter 14, respectively, but in this embodiment, the maximum value of the outputs of the voltage amplitude detecting means 16, 17, and 18 is obtained. Is detected and then input by the A / D converter 14. Reference numeral 19 is a maximum value detecting means, which outputs the maximum value of the output voltage of the voltage amplitude detecting means 16, 17, and 18. FIG. 9 is a diagram showing a circuit example of the maximum value detecting means. 29, 30 and 31 are diodes, all cathodes are connected and connected to the ground with a resistor 23, and the terminal voltage of the resistor 23 depends on the maximum value of the output voltage of the voltage amplitude detecting means 16, 17 and 18. Value is output.

FIG. 10 is a diagram showing a second example of the drive circuit of the vibration type actuator of the second embodiment. In the example of FIG. 8, the diodes 29, 30, and 31 are connected after the voltage amplitude detecting means, but in the example of FIG. 10, the diodes 29, 30, and 31 are directly connected to the vibrating bodies 1, 2, and 3. Further, the vibrating bodies 1, 2 and 3 have one terminal connected to the ground, all the cathodes of the diodes 29, 30 and 31 are connected, and are connected to the parallel circuit of the resistor 23 and the capacitor 24. By connecting in this way, the maximum value VMAX of the applied voltage of the vibrating bodies 1, 2 and 3 is output to both ends of the resistance 23.

FIG. 11 is a flowchart showing the operation of the CPU 15 of this embodiment. It is basically the same as in the first embodiment, but the drive voltage determination operation is different. In the first embodiment, the maximum value is obtained after the CPU 15 detects the voltage amplitudes of the vibrating bodies 1, 2 and 3, respectively, but in this embodiment, the maximum value VMAX of the applied voltage of the vibrating bodies 1, 2 and 3 is directly obtained. It is input by the A / D converter 14. The determination level HL uses the conversion table HL_T to obtain the determination level HL with respect to the maximum value VMAX of the applied voltage. As another example of how to obtain the determination level HL, there are a method of subtracting a predetermined value from VMAX and then multiplying the predetermined value, a method of predetermining the determination level for each VMAX range, and the like. Further, although the cathodes of the diodes 29, 30 and 31 are connected in the circuit of FIGS. 9 and 10, the anode may be connected by reversing the direction of the diode. In that case, the minimum value of the applied voltage of the vibrating bodies 1, 2, and 3 is output to the resistance 23. Since this is a value obtained by inverting the sign of the maximum value VMAX of the applied voltage, the same determination as described above can be made by inverting the sign of the value input by the A / D converter 14.

FIG. 12 is a diagram showing a third example of the drive circuit of the second embodiment. The difference from the above example is that the voltage limiting element is connected to the primary side of the transformers 5, 6 and 7. Examples of voltage limiting elements include Zener diodes and varistor. When using a Zener diode, the applied voltage is alternating current, so connect the Zener diodes in the opposite directions in series. 25, 26 and 27 are varistor. Although it is connected to the primary side of the transformers 5, 6 and 7, a voltage limiting element such as a varistor may be connected in parallel to the secondary side of the transformers 5, 6 and 7.

The above vibration type drive device can be applied to various devices.

1, 2, 3 Vibrators 4 Cylindrical shafts 5, 6, 7 Transformers 10, 28 Vibrating actuators 11 Waveform shaping means 12 Rectangular voltage generating means 13, 23 Resistance 14 A / D converter 15 CPU
16, 17, 18 Voltage amplitude detection means 19 Maximum value detection means 20, 21, 22 Inductor 24 Capacitor 25, 26, 27 Varistor 29, 30, 31 Diode

Claims (16)

A control unit that outputs a command signal and
A drive unit that outputs a drive signal based on the command signal,
A vibrating body unit in which two or more vibrating bodies vibrating based on the drive signal are connected,
A voltage detection unit for detecting an individual applied voltage in the vibrating body is provided.
The control unit is a vibration type drive device that determines a drive state of a vibrating body based on the applied voltage. The vibrating body unit in which a vibrating body is connected in parallel to the secondary side of a plurality of transformers in which the primary side is connected in series is provided, and the driving signal is applied to the primary side of the plurality of transformers. The vibration type drive device according to claim 1. The vibration type drive device according to claim 1, further comprising the vibrating body unit in which a pair of inductors and a vibrating body connected in parallel are connected in series in a plurality of pairs. The vibration type drive device according to any one of claims 1 to 3, wherein at least one of the maximum value and the minimum value of the applied voltage is detected individually. The vibration type drive device according to any one of claims 1 to 3, wherein the vibration state is determined based on either the maximum value or the minimum value of the amplitude of the applied voltage or the change with time of the applied voltage. The vibration type drive device according to any one of claims 1 to 3, wherein the vibration state is determined based on the difference between the maximum value and the minimum value of the amplitude of the applied voltage, the standard deviation, and the dispersion. The vibration type drive device according to claim 5 or 6, wherein the amplitude of the applied voltage is detected by a diode. The vibration type drive device according to claim 3, wherein the applied voltage is detected by detecting the voltage amplitude on the primary side of the transformer and estimating the amplitude of the applied voltage according to the winding ratio of the transformer. Claim 1 in which a value in which the maximum value or the minimum value of the individual applied voltage exceeds a predetermined value or a value corresponding to the individual applied voltage is set as a drive state determination value, and it is determined that the larger the value is, the worse the drive state is. The vibration type drive device according to any one of 8 to 8. Any of claims 1 to 8, wherein the individual applied voltage value exceeding a predetermined value or the value corresponding to the individual applied voltage is set as the drive state determination value, and it is determined that the larger this value is, the worse the drive state is. The vibration type drive device according to item 1. The vibration-type drive device according to claim 9 or 10, wherein the operation of the vibration-type actuator is controlled based on the sum of the drive state determination values of the individual applied voltages. The vibration-type drive device according to claim 9 or 10, wherein the operation of the vibration-type actuator is controlled based on the number of the drive state determination values exceeding a predetermined value. The vibrating drive device according to claim 2 or 3, wherein limiting means for limiting the amplitude of the applied voltage are connected in parallel to each of the plurality of vibrating bodies. The vibration type drive device according to claim 2, wherein limiting means for limiting the voltage amplitude are connected in parallel to each primary side of the transformer. The vibration type drive device according to any one of claims 1 to 14, which has a common contact body in contact with the vibrating body unit. The vibrating drive device according to claim 11, wherein the contact body is a cylindrical shaft and includes three vibrating bodies arranged substantially evenly on the circumference of the cylindrical shaft.

Images