JP2022068435A - Vibration type drive device and drive method - Google Patents

Abstract

To detect the presence or absence of disconnection or the number of disconnections of a vibration body in a vibration body unit in which a plurality of vibration bodies are connected.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, a vibration body unit in which two or more vibration bodies that vibrate on the basis of the drive signal are connected, and current detecting means that detects a current signal flowing through the vibration body unit, and the control unit determines the presence or absence of the breakage of wiring connected to the vibration body on the basis of the current signal flowing through the vibration body unit corresponding to the harmonic of a fundamental wave by using the current signal flowing through the vibration body unit corresponding to the drive frequency range of the vibration body unit as the fundamental wave.SELECTED DRAWING: Figure 1

Description

It relates to a drive device for an actuator using ultrasonic vibration.

In a vibration type actuator using a vibrating body that is vibrated by an electric-mechanical energy conversion element (piezoelectric element, electric strain element, etc.), a method of measuring the applied voltage to detect a defect such as disconnection of the vibrating body is known. ing. For example, Patent Document 1 shows an example in which disconnection is detected by detecting the generation of a high frequency component of an AC voltage applied to a vibrating body via an inductor. Further, Patent Document 2 shows an example in which disconnection is detected by detecting the Q value of the peak characteristic of the frequency characteristic of the applied voltage that changes depending on the characteristic of the transformer for boosting and the change of the peak frequency. In the case of a single vibrating body as in Patent Document 1, the change in the applied voltage due to the disconnection is large, and the occurrence of the disconnection can be detected by the generation of the high frequency component. However, a series connection type vibrating body device in which a plurality of vibrating bodies in which inductor elements are connected in parallel are connected in series, or a vibrating body is connected in parallel to the secondary side of a plurality of transformers and the primary side of each transformer is connected in series. In, even if one vibrating body is disconnected, the waveform change of the applied voltage across the series connection is small. Since the high frequency component appearing in the frequency region higher than the drive frequency increases or decreases depending on the frequency, it was not possible to determine the presence or absence of disconnection simply because the high frequency component was generated. Also, it was not possible to know the number of vibrating bodies that were broken.

Further, if a method of detecting the peak frequency and the Q value by paying attention to the peak characteristic of the frequency characteristic of the applied voltage by utilizing the frequency characteristic of the secondary side of the transformer as in Patent Document 2, a defect of each vibrating body is used. Can be detected. However, in the above-mentioned series connection type vibrating body device, it is necessary to detect the AC voltage applied to all the vibrating bodies, and it is possible to detect the defective part, but there is a drawback that the circuit scale becomes large. In addition, if frequency sweeping in the high frequency range and detection of peak frequency and Q value using pseudo-random numbers are performed independently by superimposing a high frequency voltage separately while applying a normal drive voltage, speed fluctuations and differences will occur. There was a problem that it was easy to cause sound.

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. However, there is a problem that the performance deterioration may accelerate because the load on other vibrating bodies becomes heavy in the disconnected state.

Patent No. 5716624 JP-A-2018-78769

In view of the above problems, it is an object of the present invention to detect the presence or absence of disconnection or the number of disconnections of the vibrating body in the vibrating body unit in which a plurality of vibrating bodies are connected.

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. The body unit and the current detecting means for detecting the current signal flowing through the vibrating body unit are provided, and the control unit uses the current signal flowing through the vibrating body unit corresponding to the drive frequency range of the vibrating body unit as a fundamental wave. Based on the current signal flowing through the vibrating body unit corresponding to the harmonic of the fundamental wave, it is determined whether or not the wiring connected to the vibrating body is broken.

Further, in the control method of the vibration type drive device that solves the above-mentioned problems, the control unit outputs a command signal to the drive unit, and the drive signal output by the drive unit based on the command signal causes vibration in which two or more vibrating bodies are connected. As the body unit vibrates, the control unit uses the current signal flowing through the vibrating body unit corresponding to the drive frequency range of the vibrating body unit as a fundamental wave, and the control unit corresponds to the harmonic of the fundamental wave. Based on the current signal flowing through the vibrator, it is determined whether or not the wiring connected to the vibrating body is broken.

According to the present invention, in a vibrating type drive device having a vibrating type unit in which a plurality of vibrating bodies are connected, it is possible to detect the presence or absence of disconnection or the number of disconnections of the vibrating body at the time of frequency sweep at the start of normal operation. Moreover, since the disconnection can be detected during the startup operation, the influence of the disconnection on the peripheral mechanism can be reduced.

The figure which shows the 1st example of the drive circuit of the vibration type actuator of 1st Embodiment The figure which shows the 1st example of the structure of the vibration type actuator. Diagram showing electrical connections within a vibrating actuator A flowchart showing an operation example of the CPU 15 of the first embodiment. The figure which shows the 1st example of the frequency characteristic change of the inflow current amplitude at the time of disconnection of the 1st Example. A flowchart showing an example of the startup operation of the CPU 15 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 2nd example of the frequency characteristic change of the inflow current amplitude at the time of disconnection of the 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 3rd example of the frequency characteristic change of the inflow current amplitude at the time of disconnection of the 1st Example. The figure which shows the example of the frequency characteristic change of the inflow current amplitude at the time of disconnection of the 2nd Example. A flowchart showing an example of the startup operation of the CPU 15 of the second embodiment. The figure which shows the structure of the vibrating body of the vibrating type actuator of 3rd Example. The figure which shows the vibration mode of the vibrating body of 3rd Example The figure which shows the structural example of the vibration type actuator of 3rd Example. The figure which shows the example of the drive circuit of the vibration type actuator of 3rd Example. The figure which shows the 1st example of the frequency characteristic change of the inflow current amplitude at the time of disconnection of the 3rd Example. A flowchart showing an example of the operation of the CPU 15 of the third embodiment. A flowchart showing the first and second examples of the boot operation of the CPU 15 of the third embodiment. The figure which shows the 2nd example of the frequency characteristic change of the inflow current amplitude at the time of disconnection of the 3rd Example. A flowchart showing a third example of the startup operation of the CPU 15 of the third embodiment.

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. Equipped with a unit. Further, it is provided with a current detecting means for detecting a current signal flowing through the vibrating body unit. The control unit connects the current signal flowing through the vibrating body unit corresponding to the drive frequency range of the vibrating body unit to the vibrating body based on the current signal flowing through the vibrating body unit corresponding to the harmonic of the fundamental wave. It determines whether or not the wiring is broken.

Another example of the embodiment for carrying out the present invention is the following control method.

That is, the control unit outputs a command signal to the drive unit, and the drive signal output by the drive unit based on the command signal vibrates the vibrating body unit in which two or more vibrating bodies are connected. At the same time, the control unit uses the current signal flowing through the vibrating body unit corresponding to the drive frequency range of the vibrating body unit as the fundamental wave, and the vibrating body based on the current signal flowing through the vibrating body unit corresponding to the harmonic of the fundamental wave. This is to determine whether or not the wiring connected to the wire is broken.

Hereinafter, the details will be described with reference to the drawings.

FIG. 1 is a diagram showing a drive circuit of the vibration type actuator of the first embodiment. Reference numerals 1, 2, and 3 are vibrating bodies, 5, 6, and 7 are transformers in which the primary side is connected in series, and 16, 17, and 18 are matching adjusting capacitors. Vibrators 1, 2, and 3 and matching adjustment capacitors 16, 17, and 18 are connected in parallel on the secondary side of transformers 5, 6 and 7, respectively, and the part surrounded by the dotted line is a vibration type as a vibrating body unit. The internal circuit of the actuator 10 is shown.

The inductance value of the secondary coil of the transformer connected in parallel to each vibrating body is matched at a predetermined frequency close to the resonance frequency of the vibrating actuator 10. That is, the matching frequency is F ₀ , the braking capacitance value of the piezoelectric element bonded to the vibrating body is C ₀ , the capacitance of the matching adjusting capacitor is C ₁ , and the inductance value of the secondary coil of the transformer is L ₀ . Then, these relationships are expressed by Equation 1.

１２は周波数指令に応じた駆動信号としてのパルス信号を出力する矩形電圧発生手段であり、これは駆動部として機能し、インダクタとコンデンサの直列回路で構成される波形整形手段１１を介して駆動電圧を振動型アクチュエータ１０に出力している。すなわち複数のトランスの１次側は、この駆動信号が印加されるように構成されている。

Reference numeral 12 denotes a rectangular voltage generating means for outputting a pulse signal as a drive signal in response to a frequency command, which functions as a drive unit and drives the drive voltage via a waveform shaping means 11 composed of a series circuit of an inductor and a capacitor. Is output to the vibration type actuator 10. That is, the primary side of the plurality of transformers is configured so that this drive signal is applied.

Reference numeral 13 is a resistor for measuring the current flowing through the vibrating actuator 10, which functions as a current detecting means and outputs a voltage proportional to the vibrating 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 this vibration speed with time, but since the amplitude of the vibration speed is generally proportional to the vibration amplitude, the amplitude of the vibration speed signal is controlled in the following embodiment. This controls the vibration amplitude of the vibration type actuator 10.

Reference numeral 14 is an A / D converter, and reference numeral 15 is a known CPU. The A / D converter 14 inputs the current signal detected by the resistor 13 to the CPU 15. The CPU 15 obtains the amplitude of the fundamental wave of the current signal (hereinafter, the amplitude of the fundamental wave of the current signal is referred to as vibration amplitude), and gives a frequency command to the rectangular voltage generating means 12 based on the vibration amplitude and the speed command from the command means (not shown). And the pulse width command is output.

The vibrating actuator 10 as the vibrating body unit exemplified in FIG. 1 has a configuration in which a vibrating body is connected in parallel to the secondary side of a plurality of transformers whose primary side is connected in series, and the primary side of the plurality of transformers is connected in parallel. The side is configured so that the drive signal is applied. In addition, it is provided with a waveform shaping means inserted between the rectangular voltage generating means and the 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.

Here, a first example of the vibration type actuator of this embodiment is shown. FIG. 2 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. In this embodiment, 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 1, 2, and 3 in the vertical direction. 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.

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.

FIG. 3 is a diagram showing an electrical connection in the vibrating actuator 10. Reference numerals 5, 6 and 7 are transformers, and the secondary coils of the transformers 5, 6 and 7 are connected in parallel to the vibrating bodies 1, 2 and 3 together with a matching adjusting capacitor (not shown). Reference numeral 8 is a connector for supplying a drive voltage to the vibration type actuator 10, and both ends of the series connection of the primary coil of the transformers 5, 6 and 7 are connected. Reference numeral 9 denotes a donut-shaped hollow case in which the vibrating body is housed, and these are integrated to form a vibrating actuator 10 in which a plurality of vibrating bodies are connected.

Further, the vibrating bodies 1, 2, and 3 have a protruding portion that is pressure-contacted with the cylindrical shaft 4 at every 120 ° in the hollow cylindrical portion through which the cylindrical shaft 4 of the case 9 is passed, and the support member includes a spring structure (not shown). It is pressed against the cylindrical shaft 4 with a constant pressure.

The control method of the vibration type drive device according to this embodiment is as follows. That is, the control unit outputs a command signal to the drive unit, and the drive signal output by the drive unit based on the command signal vibrates the vibrating body unit in which two or more vibrating bodies are connected. At the same time, the control unit uses the current signal flowing through the vibrating body unit corresponding to the drive frequency range of the vibrating body unit as the fundamental wave, and the vibrating body based on the current signal flowing through the vibrating body unit corresponding to the harmonic of the fundamental wave. This is to determine whether or not the wiring connected to the wire is broken.

The operation of the CPU 15 will be described with reference to the flowchart of FIG. When the speed command Vs is input from the command means (not shown), the CPU 15 starts the startup operation. The details of the start-up operation will be described separately, but in the start-up operation, the frequency command Frq and the pulse width command PW_C are output to the rectangular voltage generating means 12, the drive voltage is applied to the vibrating actuator 10, and the disconnection determination result Err is obtained by the disconnection determination. It is outputting. If the disconnection determination result Err is 1, the pulse width command PW_C is set to 0, and if the disconnection determination result Err is 0, the vibration amplitude of the vibration type actuator 10 is controlled.

In the vibration amplitude control, the vibration amplitude command Amp_C corresponding to the speed command input Vs is determined, and the operation described below is repeatedly executed until the speed command Vs becomes 0. The harmonic amplitude measurement routine measures the amplitude of the harmonic of the current signal and also measures the amplitude (vibration amplitude) Amp (1) of the fundamental wave. Specifically, a waveform of a desired order is extracted from the time-series signal first input by the A / D converter 14 with a bandpass filter, and a waveform of a fundamental wave component is also extracted. Then, the amplitude is obtained from the maximum value, the minimum value, the effective value, and the like for each component.

The pass band of the bandpass filter may include at least one of the second and third harmonics of the pulse signal.

Further, the vibration type drive device may have a configuration having either a high-pass filter that cuts the component of the fundamental wave of the current signal or a band-pass filter that detects harmonics of a specific order with respect to the fundamental wave.

Next, the vibration amplitude command Amp_C and the fundamental wave amplitude (vibration amplitude) Amp (1) are compared. Then, when the vibration amplitude Amp (1) is larger than the vibration amplitude command Amp_C, the frequency is increased by a predetermined amount, and when it is smaller than the vibration vibration command, the frequency is decreased by a predetermined amount. As a result, the amplitude (vibration amplitude) Amp (1) of the fundamental wave approaches the vibration amplitude command Amp_C. At this time, if the frequency command Frq exceeds the maximum frequency Frq_max, the frequency command is limited to the maximum frequency Frq_max. If the frequency command Frq exceeds the minimum frequency Frq_min, it is determined that there is a disconnection because the amplitude (vibration amplitude) Amp (1) of the fundamental wave does not reach the vibration amplitude command Amp_C. Then, the disconnection determination result Err is set to 1, and the pulse width command PW_C is set to 0.

If the amplitude (vibration amplitude) Amp (1) of the fundamental wave matches the vibration amplitude command Amp_C, or if the frequency command Frq does not exceed the minimum frequency Frq_min, the speed command Vs is input again and the speed command Vs becomes 0. The vibration amplitude control operation is repeatedly executed until becomes. When the velocity command Vs becomes 0 during the execution of the vibration amplitude control, the pulse width command PW_C is set to 0 and the vibration amplitude control is terminated.

Next, the startup operation will be described. FIG. 5 is a diagram showing the frequency characteristics of the current flowing into the vibrating actuator 10 that changes depending on the number of disconnections of the vibrating body of the vibrating actuator 10.

The range of the drive frequency of the vibration type actuator 10 in the present embodiment is approximately between 93 kHz and 98 kHz.

The solid line is the case where there is no disconnection, the broken line is the case where one vibrating body is broken, the alternate long and short dash line is the case where the two vibrating bodies are broken, and the dotted line is all broken. F1, which is a frequency corresponding to the range of the drive frequency of the vibration type actuator ₁₀ , is a frequency near the frequency of the valley of the current amplitude. Further, when a pulse signal is generated at a frequency F ₁ , this corresponds to a current signal as a fundamental wave flowing through the vibrating actuator 10 as a vibrating body unit. The frequency of the _second harmonic of frequency F1 is F2 _, and the frequency of the _third harmonic is F3. _In this embodiment, it can be seen that the resonance characteristic appears in the vicinity of F3 when the wire is broken. Further, the matching frequency F ₀ is set to a frequency near F ₁ .

FIG. 6 is a flowchart of a first example of the startup operation of the CPU 15. When the start-up operation is started, the frequency command Frq to the rectangular voltage generating means 12 is set to the frequency Frq0, the pulse width command PW_C is set to the drive pulse width PW0, a pulse signal is generated, and the drive voltage is applied to the vibration type actuator 10. Then, the determination result Err of the disconnection determination is set to 0, and the disconnection determination operation is started.

The disconnection determination is repeated by sweeping the frequency command Frq from the high frequency side (Frq0) to the low frequency _side until the frequency becomes F1.

The disconnection determination is performed using the amplitude Amp (3) of the third-order waveform detected by the harmonic amplitude calculation routine. The frequency Frq03 of the third harmonic at startup is three times the frequency Frq0, and as shown in FIG. 5, the frequency is near the bottom of the valley of the resonance characteristic generated when Frq03 is disconnected (near 320 kHz) or higher. Is set to. If the wire is broken, the amplitude Amp (3) of the third-order waveform may change significantly near the frequency of the valley of the resonance characteristic or become a value lower than the predetermined amplitude Amp0 during frequency sweep, so this is detected. Then, the disconnection determination Err is set to 1 and the process ends. If there is _no disconnection, the frequency sweep is continued until F1 and the disconnection determination operation is repeated.

The frequency at the bottom of the valley of the resonance peripheral characteristics (around 320 kHz) when the wire is broken is the sweep time from the frequency _Frq0 to the frequency F1 at the start, the frequency sweep speed, and the magnitude of the current of the fundamental wave component. Determined from restrictions, etc. This frequency can be arbitrarily set by adjusting the capacitance value C ₁ of the matching adjusting capacitor. That is, the capacitance value of the matching adjustment capacitor should be close to the frequency at the bottom of the valley of the resonance characteristic that appears in the frequency characteristic of the current flowing through the vibrating body unit at the time of disconnection and the frequency that is an integral multiple of the starting frequency when there is no disconnection. It is configured in.

In this case, it is more desirable that the integer multiple is 2 or 3 times in order to detect the disconnection with good accuracy without increasing the frequency sweep range.

FIG. 7 is a second example of the drive circuit of the vibration type actuator. The difference from the drive circuit of the vibration type actuator of FIG. 1 is that the waveform shaping means 11 which is a series circuit of the inductor and the capacitor is changed to the waveform shaping means 19 having only the inductor. FIG. 8 is a diagram showing an example of the frequency characteristics of the current flowing into the vibrating actuator 10 that changes depending on the number of disconnections of the vibrating body of the vibrating actuator 10 of the drive circuit of FIG. 7. Since the waveform shaping means 19 does not have a capacitor for cutting DC, the current amplitude in the low frequency region is increased as compared with the characteristics of FIG. The solid line is the case where there is no disconnection, the broken line is the case where one vibrating body is broken, the alternate long and short dash line is the case where the two vibrating bodies are broken, and the dotted line is all broken. F ₁ is a frequency near the frequency of the valley of the current amplitude, and the frequency of the second harmonic when the pulse signal is generated at the frequency F ₁ is F ₂ , and the frequency of the third harmonic is F ₃ .

It is more desirable, but not essential, to have a waveform shaping means.

Similar to the characteristics of FIG. 5, when the wire is broken _, the resonance characteristics of the current appear in the vicinity of F3. Further, as in the above description, the frequency Frq03, which is three times the frequency Frq0, is set to be near the bottom of the valley of the resonance characteristic (near 320 kHz) generated at the time of disconnection or higher. Since the description of the operation of each part is the same as the above description, the description thereof will be omitted.

FIG. 9 is a diagram showing a third example of the drive circuit of the vibration type actuator in the case where the configuration of the vibration type actuator is different. In the above example, the transformers 5, 6 and 7 and the matching adjusting capacitors 16, 17 and 18 are connected in parallel with the vibrating bodies 1, 2 and 3, but in this example, the inductor 20 and the inductor 20 are connected to the vibrating bodies 1, 2 and 3. 21, 22, and matching adjusting capacitors 16, 17, and 18 are connected in parallel. Further, the vibrating bodies 1, 2 and 3 are connected in series, and the inductors 20, 21 and 22 and the matching adjusting capacitors 16, 17 and 18 are connected in parallel, respectively, and these form a vibrating actuator 23 as a vibrating body unit. It is composed. The basic configuration of the present embodiment is to include a set of inductors, capacitors, and a vibrating body connected in parallel, and a vibrating body unit in which a plurality of sets are connected in series.

FIG. 10 shows a first example of the frequency characteristics of the current flowing into the vibrating actuator 23 when the connection of the vibrating body of the vibrating actuator 23 is broken. Similar to the above description, the frequency is swept and the amplitude of the inflow current is measured on the assumption that the rectangular voltage generating means 12 outputs a sine wave.

The solid line is the case where there is no disconnection, the broken line is the case where one vibrating body is broken, the alternate long and short dash line is the case where the two vibrating bodies are broken, and the dotted line is all broken. F ₁ is a frequency near the frequency of the valley of the current amplitude, and the frequency of the second harmonic when the pulse signal is generated at the frequency F ₁ is F ₂ , and the frequency of the third harmonic is F ₃ . Similar to the characteristics of FIGS. 5 and 8, when the wire is broken _, the resonance characteristic of the current appears in the vicinity of F3. Further, as in the above description, the frequency Frq03, which is three times the frequency Frq0, is set to be near the bottom of the valley of the resonance characteristic (near 320 kHz) generated at the time of disconnection, or higher. The disconnection is detected by the activation operation of 6.

Further, although the vibrating bodies 1, 2 and 3 are made by joining a piezoelectric element to an elastic body, only the piezoelectric body may be used. In the above description, the pulse signal which is the output of the rectangular voltage generating means 12 is used as the driving voltage, but other waveforms may be used. Even if it is a triangular wave, a sawtooth wave, or a PWM modulated wave that is the output of a known class D amplifier, if the waveform contains many relatively low-order harmonics of the 5th or lower order, the harmonic current can be detected and the disconnection can occur. It is possible to determine the presence or absence and the number of disconnections. It is more desirable to have a waveform shaping means, but it is not essential and signal processing may be performed directly.

FIG. 11 shows a second example of the frequency characteristics of the current flowing into the vibrating actuator 23 when the connection of the vibrating body of the vibrating actuator 23 is broken. What is the characteristic of FIG. 10? By adjusting the value of the matching adjusting capacitor, the frequency F3 of the _third harmonic of the pulse signal is set to the frequency near the bottom of the valley of the resonance characteristic generated at the time of disconnection (near 294 kHz). The parts are different. The configuration of the drive circuit of the vibration type actuator is the same as that in FIG. 9, but the operation of the CPU 15 is different.

The operation of the CPU 15 will be described below. FIG. 12 is a second example of a flowchart of the startup operation of the CPU 15. When the start-up operation starts, the frequency command _Frq to the rectangular voltage generating means 12 is set to the frequency F1, the pulse width command PW_C is set to the drive pulse width PW0, a pulse signal is generated, and the drive voltage is applied to the vibration type actuator 10. .. Then, the amplitude command Amp_C is set to the initial amplitude Amp1, the determination result Err of the disconnection determination is set to 0, and the disconnection determination operation is started.

The disconnection determination is performed repeatedly until the frequency command Frq is swept from the high frequency side (F ₁ ) to the low frequency side and the amplitude (vibration amplitude) Amp (1) of the fundamental wave becomes equal to or higher than the amplitude command Amp_C.

The disconnection determination is performed using the amplitude Amp (3) of the third-order waveform detected by the harmonic amplitude calculation routine. The frequency F ₃ of the third harmonic at startup is three times the frequency F ₁ , and as shown in FIG. 11, the frequency near the bottom of the valley of the resonance characteristic generated when F ₃ is disconnected (near 294 kHz). Is set to. If the wire is broken, the amplitude Amp (3) of the third-order waveform may change significantly near the frequency of the valley of the resonance characteristic or become a value lower than the predetermined amplitude Amp0 during frequency sweep, so this is detected. Then, the disconnection determination Err is set to 1 and the process ends. Also, when the frequency Frq becomes the lowest frequency Frq_min or less, the disconnection determination Err is set to 1 and the process ends. If there is no disconnection, the frequency sweep is continued and the disconnection determination operation is repeated.

Here, if the inductance value L ₀ of the secondary coil of the transformer is set so that the matching frequency F ₀ becomes equal to F ₁ , Equation 1 becomes Equation 2.

また、断線時に発生する共振特性と合わせたい高調波の次数をＮとした場合のマッチング調整用コンデンサの静電容量値Ｃ_１周波数Ｆ_１の関係は数式３であらわすことが出来る。

Further, the relationship between the capacitance value C ₁ frequency F ₁ of the matching adjustment capacitor when the order of the harmonics to be matched with the resonance characteristic generated at the time of disconnection is N can be expressed by Equation 3.

すると、数式２と数式３より制動容量値Ｃ_０と静電容量値Ｃ_１の関係は数式４であらわすことが出来る。

Then, from Equation 2 and Equation 3, the relationship between the braking capacitance value C ₀ and the capacitance value C ₁ can be expressed by Equation 4.

第１の実施例では起動時の周波数が基本波の電流振幅の谷の周波数より高い周波数Ｆｒｑ０から周波数を掃引するため起動初期の電流振幅が大きくなり、それが効率を低下させていた。これに対して実施例２では周波数Ｆ_１から周波数の掃引を開始するので従来の駆動と同等の効率にて起動動作を実行出来、断線の検出も可能である。

In the first embodiment, the frequency at the time of starting is swept from the frequency Frq0 higher than the frequency of the valley of the current amplitude of the fundamental wave, so that the current amplitude at the initial stage of starting becomes large, which reduces the efficiency. On the other hand, in the second embodiment, since the frequency sweep is started from the frequency F1, the start _- up operation can be executed with the same efficiency as the conventional drive, and the disconnection can be detected.

Further, in Examples 1 and 2, the frequency Frq03, which is three times the frequency Frq0 at the time of starting, and the vicinity of the bottom of the valley of the resonance characteristic generated at the time of disconnection (near 320 kHz) are brought close to each other. However, if the order of the harmonics contained in the pulse signal is at a certain ratio or higher, the frequency has the same magnification as the order (if the order of the harmonics is the fifth order, the frequency is five times the frequency Frq0) and the wire is disconnected. The frequencies near the bottom of the valley of the generated resonance characteristic may be brought close to each other. If the pulse width is 50% duty, there are almost no even-order harmonics, but if the pulse width becomes narrower, even-order harmonics increase. If the pulse width is narrow, the frequency may be twice the frequency Frq0 or even a higher frequency.

FIG. 13 is a diagram showing a configuration of a vibrating body used in the third embodiment. FIG. 48 in FIG. 13A is a rectangular shape made of a conductive material, and has two protrusions on the surface that come into contact with the contact body. 49 is a part of the vibrating body 48 and is a piezoelectric body for vibrating the vibrating body 48. FIG. 13B shows an electrode provided on the piezoelectric body 49, and two AC voltages whose phases change independently are applied to the electrodes 30 and 31 which are electrically insulated from each other. The entire back surface of the piezoelectric body 49 is an electrode, and is configured to be energized from the front surface through vias (not shown) provided on a part of the electrodes 30 and 31.

FIG. 14 is a diagram showing a vibration mode of the vibrating body 48. FIG. 14A shows a vibration mode (push-up vibration mode) excited when an AC voltage of the same phase is applied to the electrodes 30 and 31, and FIG. 14B shows an AC voltage of the opposite phase. It is a vibration form of a vibration mode (feed vibration mode) that is excited when applied.

That is, when the phase difference of the applied AC voltage is 0 °, the mode of FIG. 14 (a) is excited, and when the phase difference is 180 °, the mode of FIG. 14 (b) is excited. Further, when the phase difference of the AC voltage is set between 0 ° and 180 ° (actually, about 0 ° to 120 ° is used), both vibration modes are excited at the same time, and the protrusions provided on the vibrating body 48 are excited. The contact body in pressure contact moves in the longitudinal direction of the rectangle of the vibrating body 48.

FIG. 15 is a diagram showing the configuration of the direct-acting vibration type actuator of this embodiment, in which the protrusions of the vibrating bodies 36 and 37 are arranged vertically facing each other. Similarly, 5 sets of vibrating bodies are arranged in pairs up and down up to the vibrating body 38 on a straight line, and a total of 10 vibrating bodies are configured to sandwich a common contact body 50 from the vertical direction and move in the direction of the arrow. be.

FIG. 16 is a diagram showing a drive circuit of the vibration type actuator of the third embodiment. In the above embodiment, the number of vibrating bodies of the vibrating actuator is three and the number of phases of the driving voltage is one, but in this embodiment, the number of vibrating bodies is ten and the driving voltage is two phases. In the ten vibrating bodies 36, 37, ..., 38, a conductive elastic body (not shown) is connected to the ground potential.

Electrodes 30 and 31 provided in the piezoelectric body 49 are connected to the transformers 32 and 33 in parallel with the matching adjusting capacitors 34 and 35, respectively, in the vibrating body 36. Nine transformers 43, ..., 44 are connected in series to the primary side of the transformer 32, and nine vibrating bodies 37, ..., 38 are connected to the secondary side of each transformer together with a matching adjusting capacitor. The vibrating bodies are connected in parallel. Similarly, nine transformers 45, ..., 46 are connected in series on the primary side of the transformer 33, and nine vibrating bodies 37, ..., 38 are connected to the secondary side of each transformer together with a matching adjusting capacitor. The vibrating bodies of are connected in parallel. The vibration type actuator 47 is composed of 10 sets of units connected in series including these vibrating bodies, a matching adjusting capacitor, and a transformer.

Reference numeral 40 denotes a rectangular voltage generating means for outputting a two-phase pulse signal, and a driving voltage is applied to the vibration type actuator 47 via the waveform shaping means 11 and 39 composed of a series circuit of an inductor and a capacitor. 41 and 42 are resistors for measuring the two-phase currents flowing through the vibrating actuator 47, respectively, and detect voltages proportional to the vibration speeds of the vibrating bodies 36, 37, ..., 38.

24 is the amplitude (vibration amplitude) Amp (1) of the fundamental wave of the signal obtained by adding the currents detected by the resistors 41 and 42, the amplitude Amp (2) of the second harmonic, and the amplitude Amp (2) of the third harmonic. It is an amplitude detecting means for outputting 3). The amplitude (vibration amplitude) Amp (1) of the fundamental wave indicates the vibration amplitude of the push-up vibration mode of the vibrating bodies 36, 37, ..., 38, and is input to the CPU 15. The CPU 15 has a position command from a command means (not shown), a position command based on the amplitude (vibration amplitude) Amp (1) of the fundamental wave from the amplitude detection means 24, and the amplitude Amp (3) of the third harmonic, and the pulse width. The command and frequency command are determined and output. The pulse width command and the frequency command are input to the rectangular voltage generating means 40, and the frequency and the pulse width of the two-phase pulse signal to be output are set. A detailed description of the operation of the CPU 15 will be described later. Reference numeral 27 is a known linear encoder for detecting the position of the contact body 50, and 28 is a position comparison means for outputting the difference between the position command from the CPU 15 and the position signal output by the linear encoder 27. Reference numeral 29 denotes a position control means for outputting a phase difference command to the rectangular voltage generation means 40 according to the output of the position comparison means 28, and setting the phase difference of the two-phase pulse signals to move the moving direction and speed of the contact body 50. Is in control.

FIG. 17 shows a first example of the frequency characteristics of the current flowing into the vibrating actuator 47 when the vibrating body of the vibrating actuator 47 of FIG. 16 is disconnected. It is assumed that the rectangular voltage generating means 40 outputs a sine wave, the frequency is swept, and the amplitude of the inflow current is measured. The solid line is the case where there is no disconnection, the broken line is the case where one vibrating body is broken, the alternate long and short dash line is the case where the two vibrating bodies are broken, and the dotted line is all broken. F ₁ is a frequency near the frequency of the valley of the current amplitude, and the frequency of the second harmonic when the pulse signal is generated at the frequency F ₁ is F ₂ , and the frequency of the third harmonic is F ₃ .

In this embodiment, as in the second embodiment, the frequency F3 of the _third harmonic of the pulse signal is set to a frequency slightly lower than the bottom of the valley of the resonance characteristic (near 316 kHz) generated at the time of disconnection. As for the operation of the CPU 15, it is possible to determine the presence or absence of disconnection by the operation of FIG. 12 as in the second embodiment, but in this embodiment, an example of detecting the number of disconnections will be described.

FIG. 18 is a flowchart showing the operation of the CPU 15 of the third embodiment. It is a flowchart which shows the example of the operation of the CPU 15 which executes a different drive sequence of the vibration type actuator 47 depending on the disconnection result. The sequence of the position control operation of the contact body 50 is shown, and different operation sequences are selected depending on the number of disconnections (M). Each operation sequence will be described below using a flowchart. The position control operation starts when a new position command POS_C is input from a command means (not shown). First, the number of disconnections M of the oscillator that has occurred so far is confirmed. If the number of disconnections M is 2 or more, the LED for displaying the disconnection status is lit in red to end the position control operation. If the number of disconnections M is 1 or less, the vibration type actuator 47 is activated. In the start-up operation, the pulse width command PW_C is given to the rectangular voltage generating means 40, the frequency in the predetermined frequency range is swept with the predetermined pulse width, and the number of disconnection M is determined. If the number of disconnections M is 0, the LED for displaying the disconnection status is lit in green, if the number of disconnections M is 1, the LED for displaying the disconnection status is lit in yellow, and if the number of disconnections N is 2, the LED for displaying the disconnection status is orange. Lights up to execute the position control operation. When the number of disconnections is more than 2, the LED for displaying the disconnection state is turned on in red, the pulse width command PW_C is set to 0, and the vibration amplitude command AMP_C is also set to 0 to end the position control operation.

If the position control operation is not completed up to this point, the position command POS_C is set, the amplitude command AMP_C is set to the predetermined amplitude AMP0, the drive timer T is initialized to 0, and the position control operation is started. The CPU 15 controls the vibration amplitude for a certain period of time (T1) during the position control operation. The value of T1 can be set according to the moving distance according to the position command. In the vibration amplitude control routine, the frequency of the pulse signal is controlled based on the result of comparing the amplitude command AMP_C and the amplitude (vibration amplitude) Amp (1) of the fundamental wave. If the amplitude command AMP_C is larger, the frequency Frq is lowered to the low frequency side by a predetermined frequency, and if it is the opposite, the frequency Frq is raised to the high frequency side by a predetermined frequency to keep the amplitude (vibration amplitude) Amp (1) of the fundamental wave constant. I keep it in. Then, the vibration amplitude control is repeated until the drive timer T becomes T1, and when the drive timer T becomes T1, the pulse width command PW_C is set to 0, the vibration amplitude command AMP_C is also set to 0, and the position control operation is terminated.

A vibrating actuator in which a plurality of vibrating body units are connected in series, such as the vibrating actuator 47, may be able to continue driving even if some vibrating bodies are disconnected, so that driving may be continued depending on the application. .. In addition, even if the number of disconnections is small, damage will accumulate in the peripheral mechanism if driving is continued, so even if driving is continued, if the cumulative driving time exceeds a certain level, driving may be prohibited. ..

FIG. 19 shows the first and second examples of the flowchart of the startup operation of the CPU 15 of the third embodiment. FIG. 19 (a) shows the amplitude (vibration amplitude) of the fundamental wave of the pulse signal, and when the number of disconnections is detected using Amp (1), FIG. 19 (b) shows the amplitude of the third harmonic of the pulse signal, Amp (3). ) Is used to detect the number of disconnections. The following will be described while comparing each operation.

First, in both operations of FIGS. 19 (a) and 19 (b), the frequency command Frq is higher than the frequency F ₁ (near 98 kHz) near the frequency of the valley of the current amplitude and higher than the peak frequency (near 130 kHz) when there is no disconnection. Set the frequency to Frq1. The pulse width command PW_C is set to PW0. PW0 is a value at which the rectangular voltage generating means 40 outputs a pulse signal having a duty of 50%, and the rectangular voltage generating means 40 outputs a pulse signal by setting the pulse width.

The determination of the number of disconnections is repeated by sweeping the frequency command Frq from the high frequency side (Frq1) to the low frequency _side until the frequency becomes F1. At that time, the sweep for detecting the amplitude of the third harmonic is performed from the frequency Frq13, which is _three times the frequency Frq1, toward the frequency F3 of the third harmonic of the pulse signal.

First, the current amplitude used for detecting the number of disconnection M is input. Then, while sweeping the frequency, the frequency is swept until the peak characteristic (the peak of the peak of the amplitude characteristic in FIG. 17) is detected in the current amplitude used for each detection. If a peak characteristic is detected in the amplitude (vibration amplitude) Amp (1) of the fundamental wave in FIG. 19 (a) and the amplitude Amp (3) of the third harmonic in FIG. 19 (b), the frequency and disconnection of the peak characteristic are detected. The number of disconnections M is determined using a table showing the relationship of the number M. When the number of disconnections M is determined, the determination of the number of disconnections ends, the frequency command _Frq is set to the frequency F1, and the process ends. When the frequency command _Frq reaches the frequency F1 without determining the number of disconnections M, the case shown in FIG. 19A indicates that the drive circuit or the vibration type actuator 47 is out of order. In that case, the pulse width command PW_C = 0 is set, the pulse signal output of the rectangular voltage generating means 40 is stopped, and the error flag Err is set to 1. Further, in the case of FIG. 19B, when the frequency command _Frq reaches the frequency F1 without determining the number of disconnection M, the start-up operation is terminated with the number of disconnection M = 0.

FIG. 20 shows a second example of the frequency characteristics of the current flowing into the vibrating actuator 47 when the vibrating body of the vibrating actuator 47 is disconnected. It is assumed that the rectangular voltage generating means 40 outputs a sine wave, the frequency is swept, and the amplitude of the inflow current is measured. The solid line is the case where there is no disconnection, the broken line is the case where one vibrating body is broken, the alternate long and short dash line is the case where the two vibrating bodies are broken, and the dotted line is all broken. F ₁ is a frequency near the frequency of the valley of the current amplitude, and the frequency of the second harmonic when the pulse signal is generated at the frequency F ₁ is F ₂ , and the frequency of the third harmonic is F ₃ . In the characteristic of FIG. 17, the frequency at the bottom of the valley of the resonance characteristic generated at the time of disconnection is set near the frequency F3 of the _third harmonic of the pulse signal, whereas the characteristic of FIG. 20 is that of the second harmonic. _The difference is that it is set near the frequency F2.

In this example, since the frequency at the bottom of the valley of the resonance characteristic generated at the time of disconnection is close to the frequency F ₂ of the second harmonic of the pulse signal, the capacitance value C ₁ of the matching adjustment capacitor is set to the braking capacitance value C. It is set to about 1/3 of ₀ .

In addition, if frequency sweep is performed to detect the number of disconnections M when the duty of the pulse signal is 50%, a large current flows near the peak characteristics, so the current capacity of the drive circuit must be increased. There is. Therefore, the circuit cost increases and the drive efficiency decreases. Therefore, in this embodiment, this problem is avoided by reducing the duty of the pulse signal only during the start-up operation for detecting the number of disconnection M. When the duty of the pulse width is 50%, there is almost no second-order harmonic, but by reducing the pulse width, the ratio of the second-order harmonics increases, and the disconnection is determined using this.

FIG. 21 shows a third example of the flowchart of the activation operation of the PU 15 of the activation operation of the third embodiment.

Same as FIG. 19 (b) except that the amplitude Amp (2) of the second harmonic is used to determine the number of disconnections and the pulse width command PW_C is set to 1/4 of PW0 during the start-up operation. be. Here, an example using the amplitude Amp (2) of the second harmonic is shown, but it is also possible to determine the number of disconnection M using the fundamental wave as in FIG. 19 (a).

Further, in the description of Examples 1 to 3, it is assumed that the piezoelectric body is bonded to the vibrating body, but the vibrating body itself may be constructed of the piezoelectric body. Further, the piezoelectric body may be a laminated piezoelectric body.

In this way, the pulse signal output by the rectangular voltage generating means is set to a predetermined pulse width, and a current signal obtained by adding one or more phase signals of one or more phases of current flowing through the vibrating body unit. The frequency is swept until the amplitude of the fundamental wave component of is reached a predetermined amplitude.

The vibration type drive knowledge of the present invention can be used for various devices.

1, 2, 3, 36, 37, 38, 48 Vibrating body 4 Cylindrical shaft 5, 6, 7, 32, 33, 43, 44, 45, 46 Transformer 10, 23, 47 Vibration type actuator 11, 19, 39 Waveform Shaping means 12, 40 Rectangular voltage generating means 13, 41, 42 Resistance 14 A / D converter 15 CPU
16, 17, 18, 34, 35 Matching adjustment capacitor 20, 21, 22 Inductor 24 Amplitude detection means 27 Linear encoder 28 Position comparison means 29 Position control means 49 Piezoelectric body 50 Contact

Claims (25)

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 current detecting means for detecting a current signal flowing through the vibrating body unit is provided.
The control unit uses a current signal flowing through the vibrating body unit corresponding to the range of the drive frequency of the vibrating body unit as a fundamental wave, and based on a current signal flowing through the vibrating body unit corresponding to a harmonic of the fundamental wave. A vibration type drive device that determines whether or not the wiring connected to the vibrating body is broken. A vibrating body unit in which a capacitor and a vibrating body are connected in parallel is provided on the secondary side of a plurality of transformers in which the primary side is connected in series, and the driving signal is applied to the primary side of the plurality of transformers. Is configured in
The drive unit includes a rectangular voltage generating means for generating a pulse signal having a predetermined voltage and frequency, and a waveform shaping means inserted between the rectangular voltage generating means and the vibrating body unit.
The vibration type drive device according to claim 1, wherein the vibration type drive device sweeps the frequency of the pulse signal at the time of starting operation of the vibration type drive device, and detects a current signal corresponding to a harmonic of the pulse signal. .. A set of inductors, capacitors, and vibrators connected in parallel are equipped with a vibrating body unit in which multiple sets are connected in series.
The drive unit includes a rectangular voltage generating means for generating a pulse signal having a predetermined voltage and frequency, and a waveform shaping means inserted between the rectangular voltage generating means and the vibrating body unit, and the vibration type driving unit is provided. The vibration type drive device according to claim 1, wherein the device sweeps the frequency of the pulse signal at the time of starting operation of the vibration type drive device and detects a current signal corresponding to a harmonic of the pulse signal. The vibration according to any one of claims 1 to 3, comprising either a high-pass filter that cuts the component of the fundamental wave of the current signal or a bandpass filter that detects harmonics of a specific order with respect to the fundamental wave. Type drive device. The vibration type drive device according to claim 4, wherein the pass band of the bandpass filter includes at least one of the second and third harmonics of the pulse signal. The capacitance value of the capacitor is configured so that the frequency at the bottom of the valley of the resonance characteristic that appears in the frequency characteristic of the current flowing through the vibrating body unit at the time of disconnection and the frequency that is an integral multiple of the starting frequency when there is no disconnection are close to each other. The vibration type drive device according to claim 2 or 3. The vibration type drive device according to claim 6, wherein the integer multiple is 2 or 3 times. The vibration type drive device according to claim 2 or 3, wherein the pulse signal output by the rectangular voltage generating means is set to a predetermined pulse width, and the frequency is swept from a predetermined frequency to a predetermined frequency. The pulse signal output by the rectangular voltage generating means is set to a predetermined pulse width, and the current signal obtained by adding the signal of one or more phases of the current of one or more phases flowing through the vibrating body unit or the signal of some phases. The vibration type drive device according to claim 2 or 3, wherein the frequency is swept until the amplitude of the fundamental wave component of the above reaches a predetermined amplitude. The control outputs the amplitude of the harmonic of the signal of any phase or the signal obtained by adding some phases, and if the amplitude is smaller than a predetermined value, it is determined that there is a disconnection. The vibration type drive device according to item 1. The control outputs the rate of change in the amplitude of the harmonics of the signal of either phase or the signal obtained by adding several phases, and the disconnection determining means measures the case where the magnitude of the rate of change of the amplitude is larger than a predetermined value. The vibration type drive device according to any one of claims 1 to 9, wherein it is determined that there is a disconnection. The control outputs the maximum value of the harmonic amplitude of the signal of either phase or the current signal obtained by adding several phases and the frequency at that time, and the disconnection determining means has the maximum value larger than a predetermined value. The vibration type drive device according to any one of claims 1 to 9, wherein it is determined that there is a disconnection in some cases, and the number of disconnections is determined by the frequency. The vibration type drive device according to claim 2 or 3, wherein the pulse width of the pulse signal at the time of starting operation of the vibration type drive device is a pulse width smaller than the pulse width at the time of normal driving of the vibration type drive device. .. The vibration type drive device according to claim 2, wherein the number of broken wires of the wiring connected to the vibrating body is determined based on the current amplitude of the fundamental wave of the pulse signal. Claim 14 that the frequency at which the sweep of the drive signal is started is higher than the resonance frequency of the vibrating body and higher than the frequency of the peak frequency characteristic of the frequency characteristic of the current flowing through the vibrating body unit when there is no disconnection of the vibrating body. The vibration type drive device described in. The vibration type drive device according to claim 14 or 15, which comprises either a low-pass filter that cuts a harmonic component of the pulse signal or a bandpass filter that detects a fundamental wave of the pulse signal. 22. The vibration type drive device according to any one item. The vibration type drive device according to any one of claims 14 to 16, wherein the pulse width of the pulse signal in the activation operation is smaller than the pulse width at the time of normal driving. The vibrating drive device according to any one of claims 1 to 18, which has a common contact body in contact with the vibrating body unit. The vibrating drive device according to claim 19, wherein the contact body is a cylindrical shaft and includes three vibrating bodies arranged substantially evenly on the circumference of the cylindrical shaft. The vibrating drive device according to claim 19 or 20, further comprising a hollow case for accommodating the contact body and the vibrating body. The vibrating drive device according to any one of claims 1 to 21, wherein the vibrating body includes a rectangular elastic body having two protrusions and a piezoelectric body. The control unit outputs a command signal to the drive unit, and the drive signal output by the drive unit based on the command signal vibrates the vibrating body unit in which two or more vibrating bodies are connected.
The control unit uses a current signal flowing through the vibrating body unit corresponding to the range of the drive frequency of the vibrating body unit as a fundamental wave, and is based on a current signal flowing through the vibrating body unit corresponding to a harmonic of the fundamental wave. A method for controlling a vibration type drive device for determining the presence or absence of disconnection of wiring connected to the vibrating body. In the vibrating body unit, a vibrating body is connected in parallel to each of the secondary sides of a plurality of transformers to which the primary side is connected in series, and the driving signal is applied to the primary side of the plurality of transformers. It is composed and
23. The vibration according to claim 23, wherein the driving unit includes a rectangular voltage generating means for generating a pulse signal having a predetermined voltage and frequency, and a waveform shaping means inserted between the rectangular voltage generating means and the vibrating body unit. Control method of type drive device. The vibrating body unit is configured such that a set of inductors, capacitors, and vibrating bodies connected in parallel are connected in series.
23. The vibration according to claim 23, wherein the driving unit includes a rectangular voltage generating means for generating a pulse signal having a predetermined voltage and frequency, and a waveform shaping means inserted between the rectangular voltage generating means and the vibrating body unit. Control method of type drive device.

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