JP6838926B2 - Drive circuit, vibration type actuator and device having this - Google Patents

Description

The present invention relates to a drive circuit, a vibrating actuator and a device having the drive circuit.

The vibration type actuator generates high-frequency vibration in the electric-mechanical energy conversion means by applying an alternating voltage to the electric-mechanical energy conversion means such as a piezoelectric element or an electrostrictive element, and the vibration energy is continuously mechanically moved. It is taken out as. The vibrating actuator may be used separately from the controller for weight reduction. In this case, since the vibrating actuator and the controller are connected by a long bending cable, the cable may be broken, and a technique for monitoring the status of the vibrating actuator and taking appropriate measures is required.

As a method of detecting a broken cable, there is a technique of detecting the magnitude of an electric current. In this method, the current flowing into the load is measured while the vibrating actuator is being driven, and the presence or absence of a failure such as a disconnection or short circuit of the wiring path is detected by checking whether the magnitude of the current is within a predetermined range. doing. As a method of detecting the current, there are a method of connecting a resistor in series with the vibration type actuator and measuring from the terminal voltage thereof, and a method of using a known current transformer.

In Patent Document 1, a resistor for current measurement is connected in series with the piezoelectric body between the power amplifier circuit and the piezoelectric body, and the current constantly flowing into the piezoelectric body is measured to cause abnormal vibration of the vibration type actuator. A technique for measuring an abnormal current is disclosed.

Japanese Unexamined Patent Publication No. 6-303783

However, in the method of Patent Document 1, since the drive current of the vibrating actuator is measured by a resistor, there is always power consumption due to the current measurement resistor during drive. Therefore, the power usage efficiency is lowered and the total power consumption is increased. In addition, in order to detect failures such as disconnection and short circuit of all drive wires, it is necessary to insert a resistor in series in the path where all currents are combined and flow, or insert a resistor in all drive wires. Furthermore, the power consumption will increase.

The present invention has been made in view of the above problems, and an object of the present invention is to reduce power consumption in a drive circuit capable of detecting a failure such as a disconnection of a drive wire connected to a vibrating actuator as compared with the conventional case. ..

The drive circuit as one aspect of the present invention is a drive circuit that applies AC voltages having different phases to the first electric-mechanical energy conversion element and the second electric-mechanical energy conversion element of the vibrating body, and is an AC signal. And a primary winding, a first secondary winding, and a second secondary to which a second AC signal based on the first AC signal generated from the waveform generating means is input. A transformer having a side winding, one end of the first secondary winding and one end of the second secondary winding being connected by a center tap, and the first electric-mechanical energy. A current measuring means in which one end of the conversion element and one end of the second electro-mechanical energy conversion element are connected to one end and the other end is connected to the center tap, and the first secondary side. The first cable connecting the other end of the winding and the other end of the first electric-mechanical energy conversion element, the other end of the second secondary winding, and the second electric- a second cable connecting the other end of the mechanical energy conversion element, a Rukoto that having a characterized.

According to the drive circuit as one aspect of the present invention, the power consumption can be reduced as compared with the conventional case in the drive circuit capable of detecting a failure such as a disconnection of the drive wire connected to the vibrating actuator.

The schematic diagram which shows the structure of the drive circuit of 1st Embodiment. The schematic diagram explaining the structure around the vibrating body of a vibrating actuator. The schematic diagram explaining the connection relationship between the electrode structure of an electric-mechanical energy conversion means, and a drive circuit. The schematic diagram which shows an example of the waveform of AC voltage A1, B1, A2, B2. The schematic diagram which shows an example of the structure of the circuit of the failure detection means. The schematic diagram which shows the structure of the drive circuit of 2nd Embodiment. The schematic diagram explaining an example of the structure of a transformer. The schematic diagram which shows the structure of the drive circuit of 3rd Embodiment. The schematic diagram which shows the structure of the drive circuit of 4th Embodiment. The schematic diagram which shows another example of the structure of the vibration type actuator. The schematic diagram which shows the structure of the robot arm which has a vibrating type actuator.

(First Embodiment)
The drive circuit 100 of this embodiment will be described. The drive circuit 100 is a drive circuit that drives the vibrating body 20 by applying a two-phase AC voltage having a 180 ° phase difference to the electric-mechanical energy conversion means 1 of the vibrating body 20.

[Vibration actuator configuration]
The vibrating actuator 150 of the present embodiment has a vibrating body 20 having an electric-mechanical energy conversion means 1 for vibration and a drive circuit 100.

[Structure of vibrating body]
First, the configuration of the vibrating body 20 of the vibrating actuator 150 will be described with reference to FIG. FIG. 2 is a schematic view illustrating a configuration in the vicinity of the vibrating body 20. The vibrating body 20 has an electric-mechanical energy conversion means 1, an elastic body 201, and a friction material 202.

The electric-mechanical energy conversion means 1 can utilize various vibration devices such as a piezoelectric element, an electrostrictive element, and a magnetostrictive element. In the present embodiment, a commonly used piezoelectric element is used as the electric-mechanical energy conversion means 1. Therefore, in the following description, the piezoelectric element may be referred to as "piezoelectric element 1".

The piezoelectric element 1 is adhered to an elastic body 201 made of metal or ceramic, and vibration is excited by the elastic body 201 by applying an AC voltage to the piezoelectric element 1. In the vibrating body 20, a friction material 202 is arranged at a contact portion with the rotor 203, and the vibrating body 20 is pressed against the rotor 203 by a pressurizing means (not shown) with a constant pressure via the friction material 202.

The rotor 203 is a driven body in which a rotating shaft 204 for extracting rotational force to the outside is fixed at the center. When the rotor 203 is relatively driven, the elastic body 201 is formed with bending vibration (traveling wave) in which the wave crest moves in the direction opposite to the direction in which the rotor 203 is driven, and the contact portion between the friction material 202 and the rotor 203 is formed. Elliptical vibration is formed.

The piezoelectric element 1 has a plurality of electric-mechanical energy conversion elements 1-a, 1-b, 1-c, 1-d. The configuration of the piezoelectric element 1 will be described with reference to FIG. FIG. 3 is a schematic diagram illustrating a connection relationship between the electrode configuration of the piezoelectric element 1 and the AC drive voltages A1, B1, A2, and B2 generated by the drive circuit 100. The piezoelectric element 1 is a hollow annular plate, one surface of which is equally divided into 24 electrode compartments, and the other surface of which is configured as a single electrode on the entire surface. In the following description, of the piezoelectric element 1, the surface having 24 electrode sections is referred to as a front surface, and the surface facing the front surface is referred to as a back surface.

The space between the 24 electrode compartments and the back surface is pre-polarized, and the piezoelectric element is configured to be distorted by applying a voltage between the electrodes on the front surface and the back surface. Further, the electrodes on the surface are electrically connected every three on the circumference to form electrode groups 1-a, 1-b, 1-c, and 1-d. The electrode groups 1-a, 1-b, 1-c, 1-d are represented as electro-mechanical energy conversion elements 1-a, 1-b, 1-c, 1-d in the description on the circuit. That is, the piezoelectric element 1 has a plurality of electric-mechanical energy conversion elements 1-a, 1-b, 1-c, 1-d. In the following description, the electric-mechanical energy conversion elements 1-a, 1-b, 1-c, 1-d will be referred to as piezoelectric elements 1-a, 1-b, 1-c, 1-d. ..

Piezoelectric elements 1-a, 1-b, 1-c, 1-d are usually connected between electrodes by a flexible cable (not shown) bonded onto the electrodes. Four-phase AC voltages A1, B1, A2, and B2 having different phases as shown in FIG. 4 are applied to the piezoelectric elements 1-a, 1-b, 1-c, and 1-d. When an AC voltage is applied to all the electrodes of the piezoelectric elements 1-a, 1-b, 1-c, and 1-d, six elements are applied to the annular vibrating body 20 at approximately equal intervals in the direction perpendicular to the annular surface. Bending vibrations consisting of waves are formed. The waveforms of the AC voltages A1, B1, A2, and B2 as the drive voltage are sinusoidal waves that are 90 ° out of phase with each other. When such an AC voltage out of phase is applied, a progressive vibration wave is formed on the vibrating body 20 in which six bending vibrations move along the circumference of the annulus while maintaining the waveform. At this time, an ellipse that generates a tangential force in the direction opposite to the moving direction of the progressive vibration wave at the contact portion between the friction material 202 and the rotor 203 on the protrusions distributed on the circumference provided in the vibrating body 20. Vibration is formed and a relative driving force is generated between the friction material 202 and the rotor 203. Further, when the driving voltages B1 and B2 are exchanged, the traveling direction of the progressive vibration wave is reversed, and a driving force in the opposite direction is generated.

The elastic body 201 has a unique vibration mode determined by the material and shape, and the vibration mode for forming 6-wave bending vibration has a unique frequency that easily vibrates. Therefore, by bringing the frequency of the AC voltage applied to the piezoelectric element 1 close to this unique frequency (resonance frequency), this vibration can be efficiently excited.

[Structure of drive circuit 100]
The drive circuit 100 of this embodiment will be described with reference to FIG. FIG. 1 is a block diagram illustrating the configuration of the drive circuit 100 of the present embodiment.

The drive circuit 100 is a circuit that generates a two-phase AC voltage having 180 ° phases different from each other, and applies an AC voltage to the vibrating body 20 of the vibrating actuator 150. The drive circuit 100 includes a cable 2, an oscillating means (waveform generating means) 3, a transformer 4, a power amplification means 5, a CPU (control means) 6, an electric wire 7, a current measuring means 11, and a failure detecting means (determining means) 10. Have.

The oscillating means 3 outputs a sinusoidal signal having a desired frequency and voltage amplitude. The sine wave signal, which is an output signal (first AC signal) from the oscillating means 3, is amplified by the power amplification means 5 and input to the transformer 4.

The transformer 4 includes one end of the primary winding 401, the first secondary winding 402, the second secondary winding 403, and the first secondary winding 402, and the second secondary winding. It has a center tap, which is connected to one end of the wire 403. When the output signal (second AC signal) of the power amplification means 5 is input to the primary winding 401, the terminals on both sides of the center tap, that is, the first secondary winding 402 and the second secondary winding Two-phase AC drive voltages A1 and A2 having different phases of 180 ° from 403 are output.

The output signal from the transformer 4 is the first piezoelectric element 1- connected in parallel with the secondary windings 402 and 403 of the transformer 4 via the cable 2 (the first cable and the second cable). It is sent to a and the second piezoelectric element 1-c. The cable 2 is a twisted pair cable, and it is preferable that the paired electric wires have a configuration in which currents of the same magnitude and opposite phases flow to cancel each other's magnetic radiation.

The center tap of the transformer 4 and the back electrode (the back electrode of the piezoelectric element 1) (not shown) of the first and second piezoelectric elements 1-a and 1-c are connected to the resistance of the current measuring means 11 via the electric wire 7. It is connected to 8.

The CPU 6 can use a known CPU, and is a control means for setting the voltage amplitude and frequency of the sine wave signal output by the oscillation means 3 in response to an operation command from a command means (not shown).

Current measuring means 11, the current flowing through the center tap, i.e., by a means for measuring the current flowing through the wire 7, one end, one end of the one end and the second piezoelectric element 1-c of the first piezoelectric element 1-a The other end is connected to the center tap of the transformer 4.

The current measuring means 11 has a resistor 8 and a differential amplifier 9, and the differential amplifier 9 measures the potential difference between both ends of the resistor 8. The resistor 8 is inexpensive, small, and easy to use, but the method for measuring the current may be another method such as using a known current transformer. Current transformers are larger in size and may be more costly than resistors. However, in the drive circuit 100 of the present embodiment, if one current measuring means 11 is provided, a failure of a plurality of cables can be detected, so that it can be expected that the circuit can be made smaller and the cost can be reduced as compared with the conventional case.

The output voltage, which is the measurement result of the differential amplifier 9, is input to the failure detecting means 10. The failure detecting means 10 is a determining means for determining a failure based on whether or not the measurement result of the differential amplifier 9 exceeds a predetermined range, and when it is determined to be a failure, the output of the oscillating means 3 is turned off. Further, the failure detecting means 10 inputs failure information related to the failure site and the type of failure to the CPU 6.

The drive circuit 100 is used as a circuit for generating AC voltage to the first and second piezoelectric elements 1-a and 1-c. However, by preparing another set of similar drive circuits, the piezoelectric element AC voltage to 1-b and 1-d can be generated. At that time, the oscillating means corresponding to the oscillating means 3 sets the phase of the output sine wave to have a phase difference of 90 ° with respect to the sine wave output by the oscillating means 3.

[Failure detection]
Next, the behavior of the current flowing through the electric wire 7 when a failure has occurred will be described. The drive circuit 100 detects a failure by measuring the current flowing through the center tap of the transformer 4, that is, the current flowing through the electric wire 7. The behavior of the current flowing through the current 7, in a normal case, if the cable from the other end of the first secondary winding 402 to the other end of the first piezoelectric element 1-a (first cable) is disconnected , The case where the first piezoelectric element 1-a is short-circuited and the case where the electric wire 7 is broken will be described.

-Normal case First, the two secondary windings 402 and 403 of the transformer 4 are ideally manufactured completely symmetrically, and the first and second piezoelectric elements 1-a and 1-c are also completely manufactured. Assume that they have the same characteristics. Further, the contact resistance of each electric wire of the cable 2 connecting the transformer 4 and each of the first and second piezoelectric elements 1-a and 1-c and each connection pin of the connector (not shown) has the same characteristics. In that case, the current flowing through the first piezoelectric element 1-a and the current flowing through the second piezoelectric element 1-c have the same magnitude and are in opposite phases. Therefore, in the normal state, no current flows through the electric wire 7 in the ideal state.

However, in reality, the first and second piezoelectric elements 1-a, 1-c and the transformer 4 have manufacturing errors in their thickness and electrode area, and the current 7 has a constant offset alternating current. It flows. Further, while the vibration type actuator 150 is being driven, the rotor 203 rotates according to the unevenness of the surface pressure between the rotor 203 and the vibrating body 20, and the machines of the first and second piezoelectric elements 1-a and 1-c, respectively. Since the target impedance changes dynamically, the magnitude of the inflow current also changes dynamically. Therefore, the differential amplifier 9 detects a small amount of current.

- the first cable from the other end of the secondary winding 402 to the other end of the first piezoelectric element 1-a (first cable) is between the first piezoelectric element 1-a and trans 4 when disconnected When the cable (first cable) is broken, the current flowing through the second piezoelectric element 1-c has no place to go and flows through the electric wire 7. The current is large compared to the small current that flows under normal conditions. As a result, a large potential difference is generated across the resistor 8, and the output voltage of the differential amplifier 9 becomes a value larger than the voltage in the normal case.

-When the first piezoelectric element 1-a is short-circuited When the first piezoelectric element 1-a is short-circuited, the impedance of the first piezoelectric element 1-a becomes 0, and the shorted portion has been flowing until then. A current larger than the current flows. Then, the current flowing in the short-circuited portion becomes larger than the current flowing in the second piezoelectric element 1-c, and the current that has lost its place flows in the electric wire 7. As a result, a larger potential difference is generated at both ends of the resistor 8 than when the cable is broken, and the output voltage of the differential amplifier 9 is also larger than when the cable is broken.

-When the electric wire 7 is broken When the electric wire 7 is broken, almost no current flows through the resistor 8. Even if the electric wire 7 is broken, a small amount of current due to electrostatic coupling between the cable 2 and the electric wire 7 flows through the resistor 8, but usually the current is less than the current when the above-mentioned drive circuit is normal, and the differential amplifier. The output voltage of 9 is smaller than that in the normal state.

In this way, the magnitude of the current flowing through the current 7 differs depending on the state of the drive circuit, and (breakage of the electric wire 7) <(normal time) <(breakage of the cable 2 (1)) <(short circuit of the piezoelectric element). It becomes in order. Therefore, the failure can be detected by appropriately setting the threshold value. If both wires of the cable 2 are broken, the same decrease as that of the wire 7 is detected.

Such a determination method is suitable for constructing a hardware safety means such as stopping the supply power when the drive circuit fails, and the failure detection means 10 determines the range of the current value by a known comparator or the like and oscillates means. The operation of 3 is controlled.

FIG. 5 is a diagram showing a circuit example of the failure detecting means 10. The failure detecting means 10 includes an amplitude detecting means 15, comparators 16, 17, 18, and a logic OR element 19. The amplitude detecting means 15 inputs the current signal Cin output by the differential amplifier 9 and outputs the amplitude.

Each of the comparators 16, 17 and 18 is a known comparator and compares the output voltage of the amplitude detecting means 15 with a predetermined value set by the resistance voltage division. The comparator 16 has detected that the current is larger than the current at the time of disconnection, and when the signal S1 has a logical value 1, it indicates that a short circuit has occurred. The comparator 17 has detected that the current is larger than the normal current, and when the signal S2 has a logic value of 1, it indicates that the wire is broken or short-circuited. The comparator 18 has detected that the current is smaller than the normal current, and when the signal S3 has a logical value 1, it indicates that the electric wire 7 has been disconnected. As the logical OR element 19, a known three-input logical OR element can be used, and when at least one of the signals S1, S2, and S3 has a logical value of 1, a STOP signal with a logical value of 1 is output, and the oscillating means 3 is used. Operates to turn off. Further, the signals S1, S2, and S3 are input to the CPU 6, and failure information such as the position of the failure is sent to the CPU 6.

As described above, the drive circuit of the present embodiment can evaluate the presence or absence of failure of the drive circuit. The evaluation of the presence or absence of a failure of the drive circuit can be used as a means for detecting when a disconnection or a short circuit occurs while driving the vibrating actuator. Not limited to this, before driving the vibrating actuator, the drive circuit 100 may evaluate the presence or absence of a failure in the cable or the piezoelectric element, and then drive the vibrating actuator.

For example, the CPU 6 commands the oscillating means 3 to have a voltage amplitude that does not rotate the rotor 203 of the vibrating actuator (first step), and confirms the presence or absence of a failure from the signals S1, S2, and S3 (second step). ). Subsequently, the CPU 6 normally drives when there is no failure, and stops driving when there is a failure (third step). By using such a method, the current flowing at the time of short circuit can be reduced, so that the load on the circuit is small.

As another example, there is also a method of instructing the oscillating means 3 to have a normal voltage amplitude and instructing the oscillating means 3 to have a frequency sufficiently distant from the resonance frequency of the natural mode of the vibrating body 1.

In response to the signals S1, S2, and S3, the CPU 6 can notify the command means and the operator (not shown) of information such as the presence or absence of a failure and the position of the failure. For example, the logical values of the signals S1, S2, and S3 can be transmitted as they are to a command means (not shown), or the state of the signals S1, S2, and S3 can be notified to the operator by a display device such as a known LED.

As described above, the drive circuit 100 of the present embodiment includes the current measuring means 11 connected between the transformer 4 and the first and second electric-mechanical energy conversion elements 1-a and 1-c. Using the current measuring means 11, the current flowing through the center tap connecting one ends of the two secondary windings 402 and 403 of the transformer 4 is measured, that is, the current flowing through the electric wire 7 is measured. Then, by determining the presence or absence of a failure using the measurement result of the current measuring means 11, the current flowing through the electric wire 7 can be made smaller than before in the normal state. As a result, according to the drive circuit 100, the power consumption is reduced as compared with the conventional case in the drive circuit capable of detecting the failure of the vibration type actuator such as the disconnection of the drive wire connected to the vibration type actuator and the short circuit of the piezoelectric element. can do.

Further, if one current measuring means 11 is provided, it is possible to detect the failure of a plurality of cables, which can contribute to the miniaturization of the circuit scale and the cost reduction.

Further, in the case of a failure due to a disconnection or a short circuit, a larger current flows than in the normal state, so that the failure can be easily determined.

According to the drive circuit 100, since the value detected by the current measuring means 11 differs depending on the cause of the failure, the position of the failure can be acquired by the CPU 6 or the like from the measurement result of the drive circuit 100. The CPU 6 can use the measurement result of the drive circuit 100 to notify the user of information such as the presence or absence of a failure and the position of the failure, stop the operation of the vibrating actuator, and take other measures.

[Second Embodiment]
The drive circuit 600 of this embodiment will be described with reference to FIG. FIG. 6 is a block diagram illustrating the configuration of the drive circuit 600 of the present embodiment. The same configurations as those in the first embodiment are numbered the same in FIG. 6, and detailed description thereof will be omitted.

[Configuration of drive circuit 600]
The drive circuit 100 of the first embodiment is a circuit that applies an AC voltage to the first and second piezoelectric elements 1-a and 1-c. On the other hand, the drive circuit 600 of the present embodiment is connected to each of the piezoelectric elements 1-a, 1-b, 1-c, and 1-d of the vibration type actuator, and drives the vibration type actuator in a four-phase AC drive. Driven by voltage.

Driving circuit 600, similar to the drive circuit 100 of the first embodiment, the first oscillating unit 3, the first amplifying means 5, the first transformer 4, cable 2 (the first cable and the second cable ) , The electric wire 7, the current measuring means 11, the failure detecting means 10, and the CPU 6. Further driving circuit 600 has a second oscillating means 23, second amplification means 25, the second transformer 24,及beauty cable 22 (third cable and a fourth cable).

The drive circuit 600 is configured to output a four-phase AC drive voltage by two transformers 4 and 24 having a center tap. The drive circuit 600 applies four-phase AC drive voltages A1, B1, A2, and B2, which are 90 ° out of phase to the piezoelectric elements 1-a, 1-b, 1-c, and 1-d of the vibrating actuator, respectively. Apply. The CPU 6 sets the voltage amplitude, frequency, and phase difference between the four-phase signals of the first and second oscillation means 3 and 23 based on a drive command from a command means (not shown).

In addition to the parameter setting by the CPU 6, the first and second oscillation means 3 and 23 are provided with an input for turning off the output in an emergency. With such a configuration, the presence or absence of a failure is determined from the value of the current flowing through the center taps of the transformers 4 and 24, that is, the value of the current flowing through the electric wire 7, and the output of the oscillating means 3 is forcibly detected at the time of failure. Can be turned off. Since it is sufficient to determine that the current exceeds a predetermined range, it is possible to determine the failure with a relatively simple configuration without using the CPU 6.

Next, the functions of each part of FIG. 6 will be described.

The piezoelectric elements 1-a, 1-b, 1-c, and 1-d have an annular electrode structure shown in FIG. 3, and the back surface is a common electrode (not shown). When the electric-mechanical energy conversion means 1 having such a configuration is represented on the circuit diagram, four piezoelectric elements 1-a, 1-b, 1-c, 1 are centered on a common electrode on the back surface connected at one point. -D is shown in a radially connected configuration.

The second oscillating means 23 outputs an AC signal, and the AC signal is amplified by the second amplifying means 25. The amplified AC signal is input to the primary winding of the second transformer 24. The second transformer 24 has a primary winding 241 and a third secondary winding 242, and a fourth secondary winding 243, similarly to the first transformer 4. The secondary winding 242 of 3 and the 4th secondary winding 243 are connected by a center tap (second center tap). The third secondary winding 242 is connected in parallel with the third piezoelectric element 1-b, and the fourth secondary winding 243 is connected in parallel with the fourth piezoelectric element 1-d. There is.

The current measuring means 11 is a center tap on the secondary side of each of the first and second transformers 4 and 24 and the first to fourth piezoelectric elements 1-a, 1-b, 1-c and 1-d. Each is connected via an electric wire 7.

That is, cables 2, 22 and electric wires 7 are connected to the piezoelectric elements 1-a, 1-b, 1-c, and 1-d. The cables 2, 22 and the electric wire 7 are connected to the secondary windings of the first and second transformers 4, 24 having the center tap on the secondary side. Normally, each of the cables 2 and 22 is a twisted pair cable, and currents of the same magnitude and opposite phases flow through the paired electric wires to cancel each other's magnetic radiation.

The AC voltages A1, A2, B1 and B2 output by the transformers 4 and 24 are sine waves having the same amplitude with different phases by 90 ° as shown in FIG. 4 when the vibrating actuator is normally driven. The CPU 6 sets the phase difference of 90 ° between the AC voltages A1 and A2 and the AC voltages B1 and B2 in the oscillation means 3-b. The AC signals output by the first and second oscillating means 3 and 23 are power-amplified by the first and second amplifying means 5 and 25, and the primary windings 401 of the first and second transformers 4 and 24, respectively. , 241 is input.

Next, a part related to the measurement of the current flowing through the center taps of the first and second transformers 4 and 24 will be described. The configuration of the current measuring means 11 is substantially the same as that of the first embodiment. The resistor 8 measures the current flowing through the electric wire 7, and the differential amplifier 9 measures the potential difference between both ends of the resistor 8. The resistor 8 is inexpensive, small, and easy to use, but the current measurement method may be another method such as using a known current transformer.

The failure detecting means 10 determines a failure based on whether or not the output voltage of the differential amplifier 9 exceeds a predetermined range, and is configured to turn off the outputs of the oscillating means 3 and 23 when the failure occurs. Further, the failure detecting means 10 transmits information related to the failure site and the type of failure to the CPU 6.

[Failure detection]
Next, a failure detection method will be described. In the drive circuit 600, the current flowing through the center tap of the first transformer 4 (first center tap) and the second transformer 24 in center tap (second center tap), i.e. measuring the current flowing through the electric wire 7 Detects a failure. Regarding the behavior of the current flowing through the current 7, it is assumed that there is only one failure at a time, and under normal conditions, if the wire 7 is broken, the piezoelectric element 1-a and other parts from the other end of the first secondary winding 402 The case where the cable to the end (first cable) is broken and the case where the piezoelectric element 1-a is short-circuited will be described in order.

-Normal case and when the electric wire 7 is broken First, the secondary windings 402, 403, 242, and 243 of the first and second transformers 4 and 24 are ideally manufactured completely symmetrically, and the piezoelectric element. It is assumed that 1-a, 1-b, 1-c, and 1-d have exactly the same characteristics. Further, the contact resistance of each electric wire of the cables 2 and 22 connecting the transformer and the piezoelectric element and each connection pin of the connector (not shown) has the same characteristics. Then, the currents flowing through the piezoelectric elements 1-a and the piezoelectric element 1-c have the same magnitude and the opposite-phase currents flow, and the piezoelectric elements 1-b and the piezoelectric elements 1-d also have the same magnitude and the opposite-phase currents. .. Therefore, in an ideal state, no current flows through the electric wire 7. As described above, the ideal state is rare in practice, and a small amount of current flows through the electric wire 7 at normal times. However, the possibility of temporarily reaching the ideal state is not zero, and in that case, it becomes difficult to distinguish between the broken state and the normal state of the electric wire 7.

Therefore, in the present embodiment, as shown in FIG. 3, the number of electrodes of the fourth piezoelectric element 1-d is made smaller than the number of electrodes of the other piezoelectric elements to reduce the electrode area, thereby making the piezoelectric element 1-d equivalent. Set the capacitance to a value smaller than the others. With such a configuration, since a small amount of current flows through the electric wire 7 even in a normal state, the amplitude of the AC voltage output by the differential amplifier 9 becomes a value slightly larger than 0, which distinguishes it from the case where the electric wire 7 is disconnected. become able to.

The method of allowing the current to flow through the electric wire 7 in a normal state is not limited to the method of changing the equivalent capacitance of the piezoelectric element depending on the electrode area as described above, and other methods may be used. For example, as shown in FIG. 7, a method of changing the balance of the two secondary windings of the transformers 4 and 24 can be used. FIG. 7 is a schematic cross-sectional view of the winding of the transformer.

The transformer has a bobbin 70 for winding a winding, a primary winding 71, a first secondary winding 72, and a second secondary winding 73. A primary winding 71 is wound on the innermost side of the bobbin 70, and an interlayer tape for insulation (not shown) is wound on the primary winding 71, and then a first secondary winding 72 is wound on the bobbin 70. Further, an interlayer tape is wound on the first secondary winding 72, and a second secondary winding 73 is wound. A transformer having such a configuration has a positional relationship between the primary winding 71 and the first secondary winding 72, a positional relationship between the primary winding 71 and the second secondary winding 73, and a positional relationship between the primary winding 71 and the second secondary winding 73. Is different. Therefore, the resistance, inductance, and coupling coefficient of the two secondary windings 72 and 73 with the primary winding 71 are different values. Therefore, a difference is generated between the current flowing through the first secondary winding 72 and the current flowing through the second secondary winding 73, and the current flows through the electric wire 7 even in a normal state.

Further, the number of windings of the first secondary winding 72 and the number of windings of the second secondary winding 73 are different from each other, so that each of the two secondary windings 72 and 73 and the primary winding are primary. The balance may be changed by setting the ratio of the number of windings to the side windings to a different value.

- the first cable from the other end of the secondary winding 402 to the other end of the first piezoelectric element 1-a (first cable) is between the first piezoelectric element 1-a and trans 4 when disconnected When the cable (first cable) is broken, there is no place for the current flowing through the second piezoelectric element 1-c, so that this current flows through the electric wire 7 which has hardly flowed so far. This current is significantly larger than the slight current that flows due to the difference between the capacitance of the fourth piezoelectric element 1-d and the capacitance of the other piezoelectric element. As a result, a large potential difference is generated across the resistor 8, and the output voltage of the differential amplifier 9 becomes a value larger than the voltage in the normal case.

-When the first piezoelectric element 1-a is short-circuited When the first piezoelectric element 1-a is short-circuited, the impedance of the first piezoelectric element 1-a becomes 0, and the shorted portion is flowing until then. A current larger than the current flows. Then, the current flowing in the short-circuited portion becomes larger than the current flowing in the second piezoelectric element 1-c, and the current that has lost its place flows in the electric wire 7. As a result, a larger potential difference is generated at both ends of the resistor 8 than when the cable is broken, and the output voltage of the differential amplifier 9 is also larger than when the cable is broken.

Therefore, the magnitude of the current flowing through the electric wire 7 is (disconnection of the electric wire 7) <(normal state) <(disconnection of the cable 2 or the cable 22 (1)) <(short circuit of the piezoelectric element). If properly determined, the failure detecting means 10 can detect the failure. When all four wires of the cables 2 and 22 are broken, the same decrease as that of the wire 7 is detected. However, cable 2 (the first cable and the second cable) or cable 22 (the third cable and a fourth cable) of any of the electric wire is normal if disconnected with two current Since the difference is small compared to the above, a detection error may occur.

In order to reduce such a detection error, the equivalent capacitances of the second piezoelectric element 1-c and the fourth piezoelectric element 1-d are set to the first piezoelectric element 1-a and the third piezoelectric element. It is preferable that the value is smaller than the equivalent capacitance of 1-b. That is, in a normal state, the equivalent capacitances of the first and third piezoelectric elements 1-a and 1-b and the equivalent capacitances of the second and fourth piezoelectric elements 1-c and 1-d. Is different. Therefore, in the electric wire 7, the difference current I, which is the difference between the current flowing through the first piezoelectric element 1-a and the current flowing through the second piezoelectric element 1-c, and the current flowing through the third piezoelectric element 1-b. A current that is a combination of the difference current II, which is the difference between the current flowing through the fourth piezoelectric element 1-d, and the current flowing through the fourth piezoelectric element 1-d flows.

When the two wires of the cable 2 are broken, only the difference current II flows through the wire 7, and when the two wires of the cable 22 are broken, only the difference current I flows through the wire 7. Therefore, the current value is smaller than the sum of the difference current I and the difference current II in the normal state. Therefore, the magnitude of the current flowing through the electric wire 7 is (the disconnection of the electric wire 7 or the disconnection of the electric wires of the cables 2 and 22 (4)) <(the disconnection of any of the wires 2 and 22 (2) <(normal). Time) <(Breakage of either the electric wire of the cables 2 and 22 (1)) <(Short circuit of the piezoelectric element). Therefore, a failure can be detected by appropriately setting the threshold value.

In the above description, it is assumed that a disconnection or a short circuit occurs while driving the vibrating actuator, but in normal driving, a cable or a piezoelectric element is used before driving the vibrating actuator. The operation of evaluating whether or not there is a failure may be performed. For example, the CPU 6 sets the voltage amplitude and frequency of the AC signals from the first and second oscillating means 3 and 23 to the values at the time of normal startup. At that time, the CPU 6 commands the second oscillating means 23 to have a phase difference of 0 ° so as not to rotate the rotor 203 (first step). Then, the signals S1, S2, and S3 are input to confirm the presence or absence of a failure (second step), and if there is no failure, a phase difference of 90 ° is set in the oscillating means 3-b, which is normal. It starts up and stops driving if there is a failure (third step). Further, in the above description, the voltage amplitude and the frequency are set to the values at the time of normal startup, but the voltage amplitude may be made smaller than usual, or the frequency may be set to a different value.

As described above, the drive circuit 600 of the present embodiment can make the current flowing through the electric wire 7 smaller than the conventional one by determining the presence or absence of a failure by using the measurement result of the current measuring means 11. As a result, according to the drive circuit 600, the power consumption is reduced as compared with the conventional case in the drive circuit capable of detecting the failure of the vibration type actuator such as the disconnection of the drive wire connected to the vibration type actuator and the short circuit of the piezoelectric element. can do.

Further, if one current measuring means 11 is provided, it is possible to detect the failure of a plurality of cables, which can contribute to the miniaturization of the circuit scale and the cost reduction.

Further, in the case of a failure due to a disconnection or a short circuit, a larger current flows than in the normal state, so that the failure can be easily determined.

According to the drive circuit 600, since the value detected by the current measuring means 11 differs depending on the cause of the failure, the position of the failure can be acquired by the CPU 6 or the like from the measurement result of the drive circuit 600. The CPU 6 can use the measurement result of the drive circuit 600 to notify the user of information such as the presence or absence of a failure and the position of the failure, stop the operation of the vibrating actuator, and take other measures.

(Third Embodiment)
The drive circuit 800 of this embodiment will be described with reference to FIG. FIG. 8 is a schematic diagram illustrating the configuration of the drive circuit 800.

The drive circuit 800 uses a method of making the balance of the loads connected to the two secondary windings sandwiching the center tap of the transformer asymmetrical as a method of allowing a current to flow through the electric wire 7 in a normal state. Specifically, in the drive circuit 800, two passive elements 81 and 82 are connected in parallel to each of the secondary windings of the transformer 4. The passive elements 81 and 82 are passive elements having a load impedance, and the load balance can be changed by connecting elements having different load impedance values. With such a configuration, the balance of the output voltage of the transformer 4 can be slightly changed, and a current can flow through the electric wire 7 in a normal state. In the present embodiment, the passive elements 81 and 82 are connected in parallel with the transformer 4, but they may be connected in parallel or in series.

Further, as a modification of the drive circuit 800, the drive circuit 801 as shown in FIG. 8B can also be used. FIG. 8B is a block diagram illustrating an example of the configuration of the drive circuit 901.

In the drive circuit 800, the load impedance is configured by using the passive elements 81 and 82, and the load balance is made asymmetric by changing the value. On the other hand, in the drive circuit 801, the inductor elements 83 and 84 are used as passive elements to form the load impedance, and the switch 85 is used to switch between a state in which the load balance is the same and a state in which the load is different. Since the other configurations are the same as those of the drive circuit 800 shown in FIG. 8A, the same reference numerals are given and detailed description thereof will be omitted.

In FIG. 8B, the inductor elements 83 and 84 are inductor elements corresponding to the passive elements 81 and 82 of the drive circuit 800. However, the inductor elements 83 and 84 have the same inductor value, unlike the passive elements 81 and 82 described above.

Further, the drive circuit 801 has a switch 85. The switch 85 is controlled by the CPU 6 and can be switched ON / OFF. The switch 85 can switch between a state in which the inductor elements 83 and 84 and the secondary winding of the transformer 4 are connected in parallel and a state in which they are not connected. As a result, it is possible to switch between a state in which the load impedance balance is the same and a state in which the load impedance is different. It is preferable that the threshold value used by the failure detecting means 10 for determining the failure is changed in conjunction with the switching by the switch 85.

Next, the operation of the CPU 6 will be described. The CPU 6 controls the switch 85 to be turned off for a short time only when the vibrating actuator is activated, and detects a disconnection of the electric wire 7. If the electric wire 7 is not broken, the CPU 6 switches the switch 85 to ON to make the load impedance balance the same, and then normally drives the vibration type actuator. With such a configuration, the balance of the load impedance does not always become asymmetrical, and the balance of the drive voltage amplitude to the vibrating actuator does not have to be always disturbed.

In the above-mentioned drive circuit 801, the switch 85 is turned off for a certain period of time when the vibration type actuator is started, but the drive method of the drive circuit 801 is not limited to the above-mentioned method. For example, during the normal drive of the vibrating actuator, the switch 85 may be periodically turned off for a short time.

As described above, the drive circuits 800 and 801 of the present embodiment can reduce the current flowing through the electric wire 7 in the normal state by determining the presence or absence of a failure by using the measurement result of the current measuring means 11. .. As a result, according to the drive circuits 800 and 801, the power consumption of the drive circuit capable of detecting the failure of the vibration type actuator such as the disconnection of the drive wire connected to the vibration type actuator and the short circuit of the piezoelectric element is higher than before. Can also be reduced.

Further, in the case of a failure due to a disconnection or a short circuit, a larger current flows than in the normal state, so that the failure can be easily determined.

Further, according to the drive circuits 800 and 801, since the value detected by the current measuring means 11 differs depending on the cause of the failure, the position of the failure can be acquired by the CPU 6 or the like from the measurement result in the drive circuit. .. The CPU 6 can take measures such as notifying the user of a failure or stopping the operation of the vibrating actuator by using the measurement result in the drive circuit.

In the drive circuits 800 and 801 of the present embodiment, the electric wire 7 is configured so that a small amount of current flows during normal operation, so that the electric wire 7 of the vibrating actuator is disconnected and the electric wire 7 is normal. It can be determined more easily. Further, in the drive circuit 801, the impedance balance can be changed at an arbitrary timing by providing a switch. Therefore, when determining the presence or absence of a failure of the electric wire connected to the vibrating actuator and the drive circuit, it is possible to allow the current to flow through the electric wire 7 in the normal state.

(Fourth Embodiment)
The drive circuit 900 of this embodiment will be described with reference to FIG. 9A. FIG. 9A is a block diagram showing the configuration of the drive circuit 900. In the present embodiment, a configuration for protecting the resistor 8 of the current measuring means 11 is added to the drive circuit of the vibration type actuator. Further, in order to adjust the balance of the load impedance, inductor elements 91 and 92 having different inductor values are connected in series with the secondary winding of the transformer 4.

The drive circuit 900 has diodes 93 and 94. The diodes 93 and 94 are connected in parallel with the resistor 8. By providing the diodes 93 and 94, it is possible to protect the resistor 8 from burning when a disconnection or a short circuit occurs and a current flows through the resistor 8.

The configuration for protecting the resistor 8 is not limited to this, and a resistor element 95 having a positive temperature characteristic may be connected in series with the resistor 8 as in the drive circuit 901 shown in FIG. 9B. As a result, the value of the current flowing through the resistor 8 when the piezoelectric element is short-circuited can be reduced. As the resistance element 95, for example, a known PTC thermistor, polyswitch, or the like can be used.

As described above, the drive circuits 900 and 901 of the present embodiment can reduce the current flowing through the electric wire 7 in the normal state by determining the presence or absence of a failure by using the measurement result of the current measuring means 11. .. As a result, according to the drive circuits 800 and 801, the power consumption of the drive circuit capable of detecting the failure of the vibration type actuator such as the disconnection of the drive wire connected to the vibration type actuator and the short circuit of the piezoelectric element is higher than before. Can also be reduced.

Further, in the case of a failure due to a disconnection or a short circuit, a larger current flows than in the normal state, so that the failure can be easily determined. Further, the current measuring means 11 can be protected.

(Fifth Embodiment)
In the present embodiment, the robot arm 54, which is a device incorporating a vibration type actuator, will be described with reference to FIG. FIG. 11 is a schematic diagram illustrating a configuration of a system having a robot arm 54.

The system having the robot arm 54 of the present embodiment includes a controller 50, a robot arm 54, a swivel base 59, and cables (electric wires) 60 and 61. The robot arm 54 has vibrating bodies 51, 52, 53 of a vibrating actuator and a hand unit 55. The vibrating body 51 is incorporated in the joint portion of the robot arm 54, and the vibrating bodies 52 and 53 are incorporated in the grip portion of the hand unit 55. An AC voltage is applied to the vibrating bodies 51, 52, and 53 to excite the vibration, thereby driving the joint portion and the grip portion of the robot arm 54.

Each of the vibrating bodies 51, 52, and 53 is connected to the controller 50 by cables 60 and 61, and is controlled by the controller 50. It is preferable that the drive circuits of the vibrating bodies 51, 52, and 53 are included in the controller 50. The swivel base 59 changes the direction of the robot arm 54. The hand unit 56 is a unit for exchanging with the robot hand unit 55, and the gripping mechanisms 57 and 58 can be exchanged depending on the application. At that time, it is electrically connected to the controller 50 by the connector 62.

The drive circuit of the vibrating actuator in the robot arm of the present embodiment determines the presence or absence of a failure by using the measurement result of the current measuring means, and the power consumption can be reduced as compared with the conventional case.

As described above, the vibrating bodies 51, 52, and 53 of the robot hand 56 are connected to the controller 50 via the cables 60 and 61, and are arranged apart from the controller 50. Therefore, since the cables 60 and 61 are repeatedly bent and twisted, the fatigue of the electric wires is likely to proceed, and the risk of disconnection and short circuit increases. By using the drive circuit of the present embodiment, it is possible to detect failures such as disconnection and short circuit, and it is possible to reduce power consumption as compared with the conventional case. In addition, it is possible to notify the control device 6 such as a CPU or the operator of information such as a failure or failure and its position, or to operate a safety mechanism (not shown) in an emergency, when a failure is detected. Appropriate measures can be taken according to the situation.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and modifications can be made within the scope of the gist thereof.

For example, in the above-described embodiment, an annular vibrating actuator driven by a four-phase AC voltage is used as the vibrating actuator. The configuration of the vibrating actuator is not limited to this, and any vibrating actuator that is driven by an AC voltage having a phase of 180 ° may be used.

An example of the vibration type actuator is shown in FIG. 10 (a). The vibrating actuator shown in FIG. 10A has a vibrating body 40 having an electric-mechanical energy converting means 41 and a substrate 42.

The vibrating body 40 is vibrated by the electric-mechanical energy conversion means 41. As the electric-mechanical energy conversion means 41, for example, a laminated piezoelectric element sandwiched between two vibrating bodies 40 can be used. When the vibrating body 40 is vibrated by the electric-mechanical energy conversion means 41, elliptical vibration is formed on the upper surface of the vibrating body 40. The rotor 43 is a driven body that rotates due to a frictional force generated between the rotor 43 and the elliptical vibration formed on the upper surface of the vibrating body 40. The substrate 42 is a flexible substrate for supplying power to the electric-mechanical energy conversion means 41.

What kind of vibration is generated by the vibration type actuator shown in FIG. 10 (a) will be described with reference to FIGS. 10 (b) and 10 (c). FIG. 10 (c) is a schematic diagram of an electrode pattern for power supply formed in the electric-mechanical energy conversion means 41. The feeding electrode formed in the electric-mechanical energy conversion means 41 is divided into four compartments (41-a, 41-b, 41-c, 41-d). That is, the electric-mechanical energy conversion means 41 of the present embodiment has four electric-mechanical energy conversion elements (41-a, 41-b, 41-c, 41-d).

Four-phase AC drive voltages A1, B1, A2, and B2 shown in FIG. 4 having different phases by 90 ° are applied to each section. When an AC drive voltage is applied to the electric-mechanical energy conversion means 41, two bending vibrations orthogonal to the rod-shaped vibrating actuator are formed. By giving a phase shift of 90 ° to the two bending vibrations, as shown in FIG. 10B, the upper portion of the vibrating body 40 having a constriction is rotationally vibrated so as to swing around. As a result, elliptical vibration is formed on the upper part of the vibrating body 40, and the driving force is transmitted to the rotor 43 which is in pressure contact.

In the above-described embodiment, the oscillating means for outputting a sine wave is used as the oscillating means (waveform generating means) 3 and 23, but the pulse generating means for outputting a pulse signal may also be used. Even in that case, due to the nature of the low-pass filter composed of the leakage inductance of the transformers 4 and 24 and the braking capacitance of the piezoelectric element, the waveform of the AC voltage output by the transformers 4 and 24 can be obtained in a pseudo-sine wave. Can be done.

Further, in the above-described embodiment, as the vibrating body 20, a body in which a piezoelectric element is attached to an elastic body is used, but the vibrating body 20 is not limited to this configuration, and only the piezoelectric element, that is, electro-mechanical energy conversion. It may be composed of only means 1.

Further, the passive element of the third embodiment, the configuration for protecting the resistor 8 of the current measuring means 11 of the fourth embodiment, and the like can be applied to the drive circuit of the second embodiment, if necessary.

1-a 1st electric-mechanical energy conversion element 1-c 2nd electric-mechanical energy conversion element 3 Waveform generating means 4 Transformer 11 Current measuring means 401 Primary side winding 402 1st secondary side winding 403 1st 2 secondary winding

Claims (20)

A drive circuit that applies AC voltages with different phases to the first electric-mechanical energy conversion element and the second electric-mechanical energy conversion element of the vibrating body.
Waveform generation means to generate AC signals and
It has a primary winding, a first secondary winding and a second secondary winding to which a second AC signal based on the first AC signal generated from the waveform generating means is input. A transformer in which one end of the first secondary winding and one end of the second secondary winding are connected by a center tap.
A current measuring means in which one end of the first electric-mechanical energy conversion element and one end of the second electric-mechanical energy conversion element are connected to each other, and the other end is connected to the center tap. ,
A first cable connecting the other end of the first secondary winding and the other end of the first electro-mechanical energy conversion element, and
It has a second cable connecting the other end of the second secondary winding and the other end of the second electro-mechanical energy conversion element .
A drive circuit characterized in that the current measured by the current measuring means is larger when either the first cable or the second cable is broken than when it is normal. Said current measuring means, said first electric - to claim 1, wherein the Ru connect one end between one end of the mechanical energy conversion element Tei - end and the second electrical energy conversion element The drive circuit described. The current measuring means is characterized in that it measures a current flowing through an electric wire connecting each of the first electric-mechanical energy conversion element and the second electric-mechanical energy conversion element and the current measuring means. The drive circuit according to claim 1 or 2. Wherein the other end of the first secondary winding first electrical - and between said second secondary winding and the other end to the second electric the other end of the mechanical energy conversion element - machinery driving circuit according to any one of claims 1 to 3, characterized in that it comprises a passive element that is connected in parallel or in series in at least one way between the other end of the energy conversion element. The drive circuit according to claim 4, further comprising a switch for switching the connection with the passive element. Driving before Symbol according to any one of claims 1 to 3, a first secondary winding turns number and of a winding number of the second secondary winding are different from each other circuit. A claim characterized in that the coupling coefficient between the first secondary winding and the primary winding and the coupling coefficient between the second secondary winding and the primary winding are different. The drive circuit according to any one of items 1 to 3. A claim characterized in that the positional relationship between the first secondary winding and the primary winding and the positional relationship between the second secondary winding and the primary winding are different. Item 7. The drive circuit according to item 7. The drive circuit according to any one of claims 1 to 3, wherein the impedance of the first electric-mechanical energy conversion element and the impedance of the second electric-mechanical energy conversion element are different. .. Assuming that the waveform generating means is the first waveform generating means, the primary winding is the first primary winding, the transformer is the first transformer , and the center tap is the first center tap .
The vibrating body has a third electric-mechanical energy conversion element and a fourth electric-mechanical energy conversion element.
A second waveform generating means for generating an AC signal,
A second primary winding of a fourth AC signal based on the third alternating current signal generated from said second waveform generating means is input, a third secondary winding, and a fourth two- A transformer having a secondary winding and one end of the third secondary winding and one end of the fourth secondary winding connected by a second center tap.
A current in which one end of the third electric-mechanical energy conversion element and one end of the fourth electric-mechanical energy conversion element are connected to each other, and the other end is connected to the second center tap. Measuring means and
A third cable connecting the other end of the third secondary winding and the other end of the third electro-mechanical energy conversion element, and
It has a fourth cable connecting the other end of the fourth secondary winding and the other end of the fourth electro-mechanical energy conversion element .
Driving circuit according to any one of claims 1 to 9, and the center tap of the second transformer and the center tap of the first transformer is characterized in that it connects. Wherein the third end of the secondary winding third electrical - between the other end of the mechanical energy conversion element and the fourth secondary winding the other end and the fourth electrical - mechanical The drive circuit according to claim 10, further comprising a passive element connected in parallel or in series to at least one of the energy conversion elements. The drive circuit according to claim 10, wherein the number of windings of the third secondary winding and the number of windings of the fourth secondary winding are different. A claim characterized in that the coupling coefficient between the third secondary winding and the primary winding and the coupling coefficient between the fourth secondary winding and the primary winding are different. Item 10. The drive circuit according to item 10. The current measuring means includes a resistor and a measuring means for measuring the terminal voltage of the resistor.
The first electrical - end and said second electrical energy conversion element - has a between one end of the mechanical energy conversion element, wherein a resistor, a resistance element connected in series between,
The drive circuit according to any one of claims 1 to 13, wherein the resistance element has a positive temperature characteristic. The drive circuit according to any one of claims 1 to 14, further comprising a determination means for determining a state of the drive circuit based on a measurement result of the current measuring means. The drive circuit according to claim 15, wherein when the determination means determines that the drive circuit or the vibrating body is out of order, the output of the waveform generation means is stopped. The drive circuit according to claim 15, further comprising an output means for outputting failure information when the determination means determines that the drive circuit or the vibrating body has failed. The invention according to any one of claims 1 to 17, wherein an AC voltage having a 180 ° phase difference is applied to the first electric-mechanical energy conversion element and the second electric-mechanical energy conversion element. Drive circuit. With the vibrating body
The drive circuit according to any one of claims 1 to 18, wherein AC voltages having different phases are applied to the first electric-mechanical energy conversion element and the second electric-mechanical energy conversion element of the vibrating body. A vibrating actuator characterized by having and. The vibrating actuator according to claim 19,
A device comprising: a driven body driven by a vibration wave excited by the vibrating body of the vibrating actuator.

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