JP2017143602A - Control method for vibration type actuator, vibration type drive device and electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve controllability for driving a vibration type actuator.SOLUTION: A control device 140 for controlling drive of a vibration type actuator 10 has: a vibrator 15 comprising a piezoelectric element 14 and an elastic body 13 joined together; and a driven body 11 disposed in pressure contact with the vibration body 15. The control device excites vibration of the vibration body 15 by applying AC voltage to the piezoelectric element 14, detects the position of the driven body 11 moved by the excited vibration, and feedback-controls the position of the driven body 11 by using, as an operation parameter, the phase difference and frequency of an AC voltage applied to the piezoelectric element 14 on the basis of the detected position. When the driven body 11 is stopped and when it is driven at low speed, the control device 140 fixes the pulse width of a pulse signal for generating AC voltage to 25% and operates the phase difference thereof. When the driven body 11 is driven at high speed, the control device changes the pulse width of the pulse width for generating AC voltage in a range of 25% to 50% and operates the frequency thereof.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a control method for a vibration type actuator, a vibration type driving device, and an electronic apparatus.

  As a non-electromagnetic drive type actuator, a vibration type actuator is known in which a vibrating body and a driven body are brought into pressure contact, and the vibrating body and the driven body are relatively moved by vibration excited by the vibrating body. The vibrating body has, for example, a structure in which an electromechanical energy conversion element such as a piezoelectric element is bonded to an elastic body. In a vibration type actuator, an alternating drive voltage is applied to an electromechanical energy conversion element to generate high-frequency vibration in the vibrating body, and the generated vibration energy is converted into a mechanical movement called relative movement between the vibrating body and the driven body. Take out.

  Various techniques for improving the accuracy and improving the response in the control of the position and speed of the driven object in the drive mechanism using such a vibration type actuator have been proposed. Patent Document 1 proposes a control method for switching the drive voltage between when the vibration actuator is driven and when it is stopped. Specifically, speed control by frequency control is performed at the time of driving, and the driving voltage is changed to be small when stopped, and the phase difference is changed in a short time to reverse the driving direction. Patent Document 2 proposes a control method for simultaneously changing the frequency and the voltage amplitude so that an unstable operation caused by switching between the speed control based on the frequency control and the speed control based on the voltage amplitude control can be prevented. ing.

JP 2014-153497 A Japanese Patent No. 3437359

  However, it cannot be said that controllability and responsiveness are sufficient even by the application of the above-described conventional technology. For example, a mechanical resonance peak generated in a driving force transmission mechanism in the driving mechanism affects the controllability of the driving mechanism. Specifically, when the mass or inertia of the driven body is large, the mechanical resonance peak due to load fluctuation or vibration caused by insufficient rigidity or rattling of the connecting part of the vibrating body and the driven body It may occur in the vicinity of a high frequency in a control band for performing control and position control. In this case, the control gain cannot be increased sufficiently, and ringing or oscillation is likely to occur particularly during low-speed driving or when stopped.

  For example, when controlling the lens at high speed and with high accuracy in the lens driving mechanism of the camera, if the rigidity of the lens connecting portion is low, a resonance peak occurs in the vicinity of 100 to 200 Hz, which may reduce controllability. is there. In order to solve this problem, a method of reducing a resonance peak using a notch filter, a low-pass filter, or the like may be considered. However, when the resonance peak frequency is in a high-frequency range close to the control band of the vibration type actuator, if these filters are used, phase delay occurs, and as a whole, controllability cannot be improved.

  An object of this invention is to provide the technique which improves the controllability at the time of driving a vibration type actuator.

  The vibration type driving apparatus according to the present invention includes a vibration type actuator having a vibration body in which an electromechanical energy conversion element and an elastic body are joined, a driven body in pressure contact with the vibration body, and the vibration. A control device that controls the drive of the mold actuator, and the vibration device is excited by vibration excited by the vibration device by applying a plurality of AC voltages to the electro-mechanical energy conversion element by the control device. The vibration type driving device moves relative to the driven body, and the control device has a pulse width between a first pulse width and a second pulse width larger than the first pulse width. A generating unit that generates the AC voltage based on a changing pulse signal, and a relative position between the vibrating body and the driven body or the phase difference and frequency of the plurality of AC voltages as operation parameters Control means for feedback control of the degree, wherein the control means fixes the pulse width of the pulse signal to the first pulse width and stops the phase difference when the vibration type actuator is stopped and driven at a low speed. In operation, when the vibration actuator is driven at high speed, the pulse width of the pulse signal is changed in the range from the first pulse width to the second pulse width, and the frequency is operated.

  ADVANTAGE OF THE INVENTION According to this invention, the controllability at the time of driving a vibration type actuator can be improved, and especially the controllability at the time of a stop or low speed drive can be improved.

It is a block diagram which shows schematic structure of the vibration type drive device which concerns on embodiment of this invention. It is a figure explaining the schematic structure and drive mode of an example of the vibration type actuator which comprises the vibration type drive device which concerns on this embodiment. It is a block diagram which shows schematic structure of the drive part which the control apparatus which comprises the vibration type drive device which concerns on this embodiment has. It is a figure explaining the relationship between each output from the determination part and pulse width adjustment part which the control apparatus in FIG. 1 has, and the speed of a to-be-driven body. It is a flowchart of drive control of the vibration type actuator by the control apparatus in FIG. It is a figure which shows an example of the timing chart of drive control of the vibration type actuator by the control apparatus in FIG. It is a figure explaining the relationship between the pulse width of the alternating current signal output from the alternating current signal production | generation part which the control apparatus in FIG. 1 has, a fundamental wave, and a harmonic. It is a figure explaining the gain and phase delay of an open loop characteristic when a vibration type actuator is driven by each of the control device in FIG. 1 and a conventional control device. It is a figure which shows the drive current waveform corresponded to feed vibration, and its frequency analysis result when a vibration type actuator is driven by the control apparatus in FIG. It is a figure which shows the closed loop characteristic and open loop characteristic at the time of performing position feedback control with respect to a vibration type actuator with the control apparatus in FIG. It is a figure which shows the result of the positioning control at the time of the autofocus drive with the camera by each of the control apparatus in FIG. 1, and the conventional control apparatus. FIG. 3 is a diagram for explaining the gain and phase delay of the open loop characteristics when the drive control of the vibration type actuator shown in FIG. 2 is performed by changing the voltage or the drive frequency with a constant pulse width. It is a perspective view which shows schematic structure of the lens drive mechanism to which a vibration type drive device is applied. FIG. 2 is a plan view illustrating an appearance of an imaging apparatus to which a vibration type driving device is applied, and a diagram illustrating a schematic structure inside the imaging apparatus. It is an external appearance perspective view of the microscope to which a vibration type drive device is applied.

  FIG. 1 is a block diagram showing a schematic configuration of a vibration type driving apparatus 150 according to an embodiment of the present invention. The vibration type driving device 150 includes the vibration type actuator 10, a control device 140, and a position detection unit 145. The control device 140 includes a control unit 120 and a drive unit 130. The control unit 120 includes a command value generation unit 101, a control amount calculation unit 102, a pulse width adjustment unit 107, a subtractor 108 and a phase difference / frequency control unit 110. The phase difference-frequency control unit 110 includes a phase difference conversion unit 103, a frequency conversion unit 104, and a phase difference-frequency determination unit 106 (hereinafter referred to as "determination unit 106"). The drive unit 130 includes an AC signal generation unit 111 and a booster circuit 112.

  First, the schematic configuration and drive mode of the vibration type actuator 10 will be described. 2 is a linear vibration actuator that is an example of a vibration actuator that is subject to drive control by the control device 140. The vibration actuator 10 illustrated in FIG. FIG. 2A is a perspective view showing a schematic configuration of the vibration type actuator 10. FIG. 2B is a plan view for explaining an electrode pattern and a polarization region formed on the piezoelectric element 14 constituting the vibration type actuator 10. FIG. 2C is a diagram schematically illustrating the first vibration mode excited by the vibrating body 15 constituting the vibration type actuator 10. FIG. 2D is a diagram schematically illustrating the second vibration mode excited by the vibrating body 15 constituting the vibration type actuator 10. 2C and 2D exaggerately show how the vibrating body 15 is deformed.

  The vibration type actuator 10 includes a vibration body 15 and a driven body 11. The vibrating body 15 includes an elastic body 13, two protrusions 12, and a piezoelectric element 14. The elastic body 13 is a thin plate member made of, for example, a stainless material. The protrusion 12 is made of a stainless material or the like, and is formed integrally with the elastic body 13 on one surface of the elastic body 13 or joined by welding or the like. The piezoelectric element 14 that is an electro-mechanical energy conversion element is bonded to the surface of the elastic body 13 opposite to the surface on which the protrusions 12 are provided by an adhesive or the like. The vibrating body 15 and the driven body 11 are pressed against the upper surface of the protruding portion 12 by a pressing means (not shown) with the protruding direction of the protruding portion 12 (the Z direction shown in FIG. 2C) as the pressing direction. doing.

  The piezoelectric element 14 is formed with an electrode region equally divided into two in the direction X connecting the two protrusions 12, and the polarization direction in each electrode region is the same direction (+). Of the two electrode regions of the piezoelectric element 14, an AC drive voltage VA is applied to the left electrode region (A phase) in FIG. 2B, and an AC drive voltage is applied to the right electrode region (B phase). VB is applied. Thereby, the vibration body 15 is vibrated in the first vibration mode and the second vibration mode.

  Specifically, when the drive voltages VB and VA are set to have a frequency in the vicinity of the resonance frequency of the first vibration mode and the same phase, the entire piezoelectric element 14 expands at a certain moment and contracts at another moment. As a result, vibration in the first vibration mode is generated in the vibrating body 15. The first vibration mode is a vibration mode in which two nodal lines are generated substantially parallel to the direction connecting the two protrusions 12 (X direction). The protrusion 12 is provided in the vicinity of the position where the vibration is caused and vibrates (displaces) in the Z direction, which is the protrusion direction of the protrusion 12. Hereinafter, the vibration in the first vibration mode is referred to as “push-up vibration”. Further, when the drive voltages VB and VA are alternating voltages having a frequency near the resonance frequency of the second vibration mode and the phase is shifted by 180 degrees, the electrode region on the right side of the piezoelectric element 14 is contracted at a certain moment. The electrode region on the left extends, and the reverse relationship is observed at another moment. As a result, vibration of the second vibration mode is generated in the vibrating body 15. The second vibration mode is a vibration mode in which three nodal lines are generated substantially parallel to the Y direction orthogonal to the X direction and the Z direction. The protrusion 12 is provided in the vicinity of a position that becomes a node of the vibration, and is displaced in the X direction. Hereinafter, the vibration in the second vibration mode is referred to as “feed vibration”.

  Therefore, by applying the drive voltages VB and VA to the electrodes of the piezoelectric element 14 as alternating voltages having frequencies close to the resonance frequencies of the first vibration mode and the second vibration mode, the push-up vibration and the feed vibration are synthesized. Vibration can be excited. By combining the thrust vibration and the feed vibration, the protrusion 12 performs an elliptical motion in the ZX plane, and the driven body 11 and the vibrator 15 are relatively moved in the X direction by the elliptical motion. Can be moved. At this time, by changing the phase difference between the drive voltages VB and VA, the amplitude ratio between the push-up vibration and the feed vibration can be changed. "Speed") can be adjusted.

  Such a vibration type actuator 10 is used, for example, for lens drive of a focus lens in an imaging apparatus such as a camera. By connecting a holding member that holds the focus lens to the driven body 11, the holding member is made optical. It can be moved in the axial direction. At that time, since highly accurate positioning control is necessary for driving the lens, position feedback control using a position sensor is generally performed. By adjusting the frequency, phase difference, pulse width, and the like of the drive voltages VA and VB applied to the piezoelectric element 14, the speed of the driven body 11, that is, the speed of the focus lens can be controlled. For example, the control device 140 drives the vibration actuator 10 so that the focus lens accelerates from a stationary state to a predetermined speed, decelerates and stops at the target position as it approaches the target position after moving at a constant speed. Control. Here, when speed is desired for autofocus, it is necessary to move the focus lens at a high speed to reach the target position in a short time. In this case, it is important to suppress ringing after raising the control gain and improving the followability, and this is necessary for heavy lenses and lenses with high sensitivity (degree of movement distance of the image plane relative to movement distance). Remarkably required.

  The control device 140 has a configuration corresponding to such a need. Next, the configuration and operation of the control device 140 will be described in detail. In the following description, “drive the vibration type actuator 10” means that the driven body 11 and the vibration are controlled by controlling the vibration in the first vibration mode and the vibration in the second vibration mode that are excited by the vibration body 15. It refers to controlling the relative position change of the body 15. In the following description, for convenience, the vibrating body 15 is fixed to a fixing means (not shown), and the control device 140 moves the driven body 11 with respect to the vibrating body 15 as a moving body. The description will be made assuming that 10 is driven.

  The position detection unit 145 included in the vibration type driving device 150 includes a position sensor such as a linear encoder and an arithmetic circuit that detects the position of the driven body 11 based on an output signal from the position sensor. The position signal 141 output from the position detection unit 145 is input to the subtracter 108 included in the control unit 120. In the block diagram of FIG. 1, the position detection unit 145 is a component that is removed from the control device 140, but the control device 140 may of course be configured to include the position detection unit 145.

  The control unit 120 includes various electronic devices and electrical components such as a CPU, a PLD (including an ASIC), a ROM, a RAM, and an A / D converter, and controls the driving of the vibration actuator 10. A signal having the following information is generated. The command value generation unit 101 generates, for example, one command value related to the position of the driven body 11 and outputs it to the subtracter 108 at every control sampling (every time) of the position of the driven body 11. The “control sampling” refers to the acquisition of the deviation 142, which will be described later, the application of the driving voltages VA and VB to the vibrating body 15, the detection of the speed and position of the driven body 11, and immediately before the acquisition of the deviation 142 starts. 1 cycle. Then, in this one cycle, the position (or speed) of the driven body 11 is feedback-controlled. The “command value related to the position of the driven body 11” is a value related to the position of the driven body 11 output from the command value generation unit 101 every time. For example, one command value is output from the command value generation unit 101 for each control sampling.

  The subtractor 108 calculates a difference between the position signal 141 related to the driven body 11 detected by the position detection unit 145 and the command value as a deviation 142, and outputs the calculated deviation 142 to the control amount calculation unit 102. The control amount calculation unit 102 calculates the control amount 143 using the deviation 142, and outputs the calculated control amount 143 to the phase difference conversion unit 103 and the frequency conversion unit 104 constituting the phase difference-frequency control unit 110. The control amount calculation unit 102 calculates the control amount 143 using, for example, a PID compensator. The PID compensator is obtained by adding the outputs of compensators having proportional (P), integral (I), and derivative (D) functions, and compensates for the phase delay and gain of the controlled object, and is stable. Moreover, it is generally used to construct a highly accurate control system.

  The phase difference-frequency control unit 110 plays a role of controlling the amplitude and amplitude ratio of the push-up vibration and the feed vibration based on the control amount 143. The phase difference conversion unit 103 and the frequency conversion unit 104 each have a control amount 143 as a phase difference and a frequency that are operation parameters of an AC signal that is a pulse wave for generating drive voltages VA and VB supplied to the vibration actuator 10. To each control amount. The phase difference conversion unit 103 outputs the generated phase difference control amount θ to the determination unit 106 and the pulse width adjustment unit 107, and the frequency conversion unit 104 outputs the generated frequency control amount F to the determination unit 106 and the pulse width adjustment. Output to the unit 107.

  The pulse width adjustment unit 107 determines a pulse width (PW) based on the phase difference control amount θ and the frequency control amount F using a look-up table, an arithmetic expression, or the like, and determines the determined pulse width as a drive unit. It outputs to 130 alternating current signal production | generation part 111. FIG. The pulse width is controlled in accordance with changes in the phase difference control amount θ and the frequency control amount F, with the first pulse width (PW1) being the lower limit value and the second pulse width (PW2) being the upper limit value. Updated every sampling. Specific examples thereof will be described later. Based on the phase difference control amount θ and the frequency control amount F, the determination unit 106 generates a frequency and phase difference control amount for controlling the speed and driving direction of the driven body 11, and the AC of the driving unit 130. Output to the signal generator 111.

  The AC signal generation unit 111 includes, for example, a CPU, a function generator, a switching circuit, and the like. The AC signal generation unit 111 generates a rectangular wave AC signal based on the control amounts of the phase difference and the frequency input from the determination unit 106 and the information on the pulse width input from the pulse width adjustment unit 107. . The AC signal generation unit 111 outputs the generated two-phase AC signal to the booster circuit 112. The booster circuit 112 boosts the AC signal input from the AC signal generator 111 to a predetermined voltage value to generate AC drive voltages VA and VB, and applies the generated drive voltage to the piezoelectric element 14 of the vibrating body 15. To do. Thereby, the driven body 11 is frictionally driven by the vibrating body 15, and the driven body 11 can be moved at a predetermined speed in a predetermined direction. As described above, the position of the driven body 11 is detected by the position detector 145, and the position signal 141 output from the position detector 145 is input to the subtractor 108 and then fed back to the control amount calculator 102 as a deviation 142. Is done. In this way, the vibration type actuator 10 is feedback controlled so as to follow the command value for each time.

  Here, the configuration of the drive unit 130 will be described in detail. Note that, in the drive unit 130, the configuration used for generating the drive voltages VA and VB applied to the piezoelectric element 14 is the same, and therefore, the portion used for generating the drive voltage VA will be described here.

  FIG. 3A is a block diagram illustrating a schematic configuration of the AC signal generation unit 111 and the booster circuit 112. The AC signal generation unit 111 includes a pulse signal generation unit 165 and a switching circuit 160. Further, the booster circuit 112 includes a coil 162 and a transformer 163. The pulse signal generation unit 165 includes a rectangular A-phase pulse signal having phase difference, frequency, and pulse width information corresponding to information from the determination unit 106 and the pulse width adjustment unit 107, and the phase of the A-phase pulse signal is 180. A phase-inverted pulse signal shifted by a degree is generated. FIG. 3B is a diagram illustrating a pulse signal generated by the pulse signal generation unit 165. The A-phase pulse signal and the A-phase inverted pulse signal generated by the pulse signal generation unit 165 are input to the switching circuit 160. The switching circuit 160 switches the DC voltage supplied from the power supply 161 at the timing of the input pulse signal, and generates a rectangular wave AC signal. When the pulse width of the pulse signal generated by the pulse signal generation unit 165 is represented by a duty ratio, the pulse width of the AC signal generated by the AC signal generation unit 111 is also represented by the same duty ratio.

  The AC signal output from the AC signal generation unit 111 is input to the booster circuit 112 and boosted to a predetermined voltage value to be converted into a sin-wave drive voltage VA. One electrode (A phase) of the piezoelectric element 14 ). The B-phase pulse signal used to generate the drive voltage VB applied to the other electrode (B-phase) of the piezoelectric element 14 is information on the phase difference output from the determination unit 106 with respect to the A-phase pulse signal. To have a predetermined phase difference based on The B-phase inversion pulse signal is generated so that the phase is 180 degrees out of phase with the B-phase pulse signal. The sin wave drive voltage VB is generated in the same manner as the drive voltage VA.

  Next, a method for controlling the vibration type actuator 10 by the control device 140 will be described. FIG. 4 is a diagram for explaining the relationship between the outputs of the determination unit 106 and the pulse width adjustment unit 107 and the speed of the driven body 11. FIG. 4A shows the relationship between the drive frequency and the speed of the driven body 11. At the upper limit f0 of the drive frequency, feedback control for low-speed drive by phase difference control is performed. At that time, in the range of the speed from −V1 to + V1 (including driving stop), the pulse width output from the pulse width adjustment unit 107 is, for example, 25% (the duty ratio is 25%, and so on) The same applies to the ratio of PW1). That is, when the control amount θ of the phase difference changes, the pulse width is fixed at PW1. On the other hand, when the speed is in the range of + V1 to + V2 and in the range of −V1 to −V2, high-speed drive feedback control by frequency control is performed. At that time, the drive frequency is operated in the range of the upper limit value f0 to the lower limit value f1, and the pulse width output from the pulse width adjustment unit 107 is between PW1 and a larger width PW2 (for example, 50%). The range is adjusted according to the operation amount of the drive frequency. That is, when the frequency control amount F changes, the pulse width output from the pulse width adjustment unit 107 is changed in a range between PW1 and PW2 in accordance with the frequency control amount F. The drive control that efficiently uses the speed that can be generated in the motor 11 is possible. When the deviation 142 in the feedback control becomes zero as in the case where the driven body 11 is maintained in a stopped state, the frequency control amount F does not change. In this case, even if the phase difference control amount θ does not change, the pulse width output from the pulse width adjustment unit 107 is fixed to PW1.

  FIG. 4B shows the relationship among the control amount 143, the output from the control unit 120, and the speed of the driven body 11. The determination unit 106 sets a region where the absolute value of the control amount 143 is small as a phase difference control region in which the phase difference between the two-phase drive voltages VA and VB for driving the vibration actuator 10 is changed. To control. On the other hand, the determination unit 106 controls the drive frequency and the phase difference as a frequency control region in which the drive frequency of the two-phase drive voltages VA and VB is changed in a region where the absolute value of the control amount 143 is large. Thus, the determination unit 106 switches between phase difference control and frequency control according to the control amount 143.

  Specifically, in the phase difference control region, the drive frequency is fixed to the upper limit value f0, and the phase difference between the two-phase drive voltages VA and VB is changed between the upper limit value and the lower limit value. The movement direction is reversed and stopped, and the speed of the driven body 11 in the low-speed drive region is controlled. In the meantime, the pulse width adjustment unit 107 always outputs PW1, which is a small pulse width. Further, the control range of the phase difference control amount θ may be, for example, a range of −90 degrees to +90 degrees, but is not limited thereto, and is in a range of −60 degrees to +60 degrees or −120 degrees to +120 degrees. It is good also as the range. As shown in the lower part of FIG. 4B, the speed of the driven body 11 changes according to the control amount 143, but in the low speed driving region of −V1 to + V1 (for example, −50 to +50 mm / s). Phase difference control is performed. In the phase difference control, by controlling the phase difference between the two-phase drive voltages VA and VB, the ellipticity of the elliptical motion of the protrusion 12 provided on the vibrating body 15 is changed, and the sign of the phase difference is inverted. To reverse the direction of the elliptical motion. Note that when the movement locus of the protrusion 12 becomes a vertically long shape and the ellipticity ratio becomes zero, the speed of the driven body 11 becomes zero.

  On the other hand, in the frequency control region, which is a high-speed drive region, the phase difference control amount θ is fixed to the lower limit value or the upper limit value, and the drive frequency is between the upper limit value f0 (for example, 90 kHz) and the lower limit value f1 (for example, 88 kHz). As a result, the speed of the driven body 11 is controlled. As shown in the lower part of FIG. 4B, frequency control is performed in a high-speed drive region where the speed of the driven body 11 is + V1 to + V2, −V1 to −V2 (for example, 50 to 100 mm / s). In the frequency control, by controlling the driving frequency, the ellipticity of the elliptical motion of the protrusion 12 provided on the vibrating body 15 is made constant, and the elliptical amplitude is changed. In such control, the phase difference-frequency control unit 110 sets the phase difference and the frequency so that the speed is as linear as possible with respect to the control amount 143. Note that when the pulse width output from the pulse width adjustment unit 107 in frequency control increases, the open loop response gain increases. Therefore, in frequency control, the control gain can be reduced by that amount compared to phase difference control. desirable.

  FIG. 5 is a flowchart of drive control of the vibration type actuator 10 (position feedback control of the driven body 11) by the control device 140. As described above, the control unit 120 includes a CPU, a ROM, a RAM, and the like, and each process in the flowchart of FIG. 5 is performed by the CPU developing a program stored in the ROM in the RAM, This is realized by controlling the operation.

  When the power source of the control device 140 is turned on, in step S1, the CPU sets the frequency, phase difference, and pulse width of the AC signal for generating the two-phase drive voltages VA and VB to initial values. In step S <b> 2, the CPU detects the current position of the driven body 11 using the position detection unit 145, and calculates a deviation 142 between the generated position signal 141 and the command value output from the command value generation unit 101. In step S <b> 3, the CPU calculates the phase difference control amount θ and the frequency control amount F based on the deviation 142 by the phase difference conversion unit 103 and the frequency conversion unit 104. In step S4, the CPU determines whether or not the calculated control amount θ of the phase difference is within a predetermined threshold range. The threshold value is set to ± 90 degrees, for example, but is not limited to this, and may be another value such as ± 80 degrees or ± 100 degrees. If the phase difference control amount θ is within the threshold range (YES in S4), the CPU proceeds the process to step S5, and if the phase difference control amount θ is not within the threshold range (NO in S4), The process proceeds to step S8.

  In steps S5 to S7, phase difference control is executed. In step S5, the CPU sets the drive frequency of the AC signal generated by the AC signal generation unit 111 to the upper limit value f0. In step S6, the CPU sets the pulse width of the AC signal (pulse signal generated by the pulse signal generation unit 165) generated by the AC signal generation unit 111 to PW1. In step S <b> 7, the CPU changes the phase difference of the AC signal generated by the AC signal generation unit 111 based on the control amount θ of the phase difference. Thereafter, the process proceeds to step S10. Note that the processes in steps S5 to S7 are performed simultaneously.

  In steps S8 to S9, frequency control is executed. In step S8, the CPU sets the control amount θ of the phase difference as a threshold value. In step S9, the CPU simultaneously changes the pulse width and drive frequency of the AC signal generated by the AC signal generation unit 111 based on the frequency control amount F, and then advances the process to step S10. Here, in step S9, the pulse width of the AC signal is changed in the range of PW1 to PW2, the drive frequency is changed in the range of the upper limit value f0 to the lower limit value f1, and basically the pulse is lowered as the drive frequency is lowered. The width is controlled to increase (see FIG. 4). In step S9, PW1 has a smaller duty ratio than PW2 and a higher ratio of harmonics to the fundamental wave. As the pulse width changing method based on the frequency control amount F, for example, table data or an arithmetic expression can be used, and the pulse width may be changed continuously or discretely. .

  In step S <b> 10, the CPU determines whether or not the driven body 11 has reached the target position based on whether or not a stop command is input after a predetermined settling time. When the stop command is not input (NO in S10), the CPU returns the process to step S2, whereby the position feedback control by phase difference control or frequency control is repeated for each control sampling toward the target position. On the other hand, when the stop command is input (YES in S10), the CPU advances the process to step S11. In step S11, the CPU sets the pulse width to PW1 or less. Thereby, the drive control of the vibration type actuator 10 is completed.

  FIG. 6 is an example of a timing chart of drive control by the control device 140. The command value is position information set every time by the command value generation unit 101, and is output from the drive start position of the driven body 11 to the target position, for example, by drawing an S-shaped curve. The driving of the vibration type actuator 10 is controlled so as to follow a command value that changes with time. At times t0 to t1 immediately after the start of driving, for the driving voltages VA and VB for driving the vibration type actuator 10, the driving frequency is set to the upper limit value f0, and the phase difference is operated from 0 degree to +90 degrees. Thereby, the driven body 11 is accelerated, and the speed of the driven body 11 reaches speed + V1 (for example, 50 mm / s) at time t1. Between times t0 and t1, in the AC signal (first pulse signal) generated by the AC signal generation unit 111, the pulse width (pulse width of the pulse signal generated by the pulse signal generation unit 165) is PW1 (25 %).

  From time t1 to time t2, the speed of the driven body 11 reaches speed + V1 to + V2 (for example, 100 mm / s). Meanwhile, the drive frequency is operated from the upper limit value f0 to the lower limit value f1, and the AC signal generated by the AC signal generation unit 111 according to the operation amount of the drive frequency is the first with a pulse width of 25% (PW1). The pulse signal is changed to a second pulse signal of 50% (PW2). At times t2 to t3, the drive frequency is returned to the upper limit value f0, and the pulse width is also returned to PW1, whereby the speed of the driven body 11 is reduced from + V2 to + V1. The phase difference is fixed at +90 degrees between times t1 to t3 when the drive frequency is operated. At times t3 to t4 before the driven body 11 reaches the target position, the driving frequency is operated from the upper limit f0 and the phase difference from +90 degrees to 0 degrees. As a result, at time t4, the driven body 11 is stopped at a speed of zero. Ideally, the phase difference is 0 degree and the speed is zero. However, depending on the individual difference of the vibration actuator 10 and the environment, the phase difference is a value near 0 degree and the speed is zero. That is, the condition for stopping the driven body 11 depends on the value of the deviation 142 of the position feedback control.

  After the driven body 11 reaches the vicinity of the target position at time t4, positioning control is performed while repeating the advance operation and the return operation at a predetermined settling time. After the driven body 11 is set to the target position with a predetermined accuracy, the driven body 11 is held at the target position. There is no limitation on the method of holding the driven body 11 at the target position. For example, the pulse width of the AC signal generated by the AC signal generation unit 111 is set to zero and the power supply to the piezoelectric element 14 is turned off to save power. Can be achieved. Further, the pulse width of the AC signal generated by the AC signal generation unit 111 may be changed without changing or in the range of 0 to 25% and the phase difference may be set to 0 degree. At time t5 to t6, the driven body 11 is driven from the target position to the start position. However, the drive control at that time is only different in the driving direction of the driven body 11, and at the time t0 to t4 described above. Since it is performed in the same manner as the drive control of the driven body 11, a detailed description thereof is omitted.

  Prior to describing in more detail the characteristics of the drive control of the vibration type actuator 10 by the control device 140 described above, the fundamental wave and the harmonics of the AC signal output from the AC signal generation unit 111 will be described. FIG. 7 is a diagram illustrating the relationship between the pulse width of the pulse signal output from the pulse signal generation unit 165 of the AC signal generation unit 111, the fundamental wave, and the harmonics. FIG. 7A shows temporal changes of the A-phase pulse signal and the B-phase pulse signal when the pulse width is 50%. Between time t10 and t14 is one cycle of the driving frequency for driving the vibration type actuator 10, and the A phase pulse signal and the B phase pulse signal are output at the Hi level for a time corresponding to 50% of the cycle. It is a pulse signal. Further, when the phase difference between the A-phase pulse signal and the B-phase pulse signal is set to +90 degrees, the rising edges of the A-phase pulse signal and the B-phase pulse signal are shifted by a quarter cycle (time t10 and time t11). Is output.

  FIG. 7B shows temporal changes in the A-phase pulse signal and the B-phase pulse signal when the pulse width is 25%. From time t15 to t19 is one cycle of the driving frequency for driving the vibration type actuator 10, and the A phase pulse signal and the B phase pulse signal are pulses whose time corresponding to 25% of the cycle is output at the Hi level. Signal. When the phase difference between the A-phase pulse signal and the B-phase pulse signal is +90 degrees, the rise of the A-phase pulse signal and the B-phase pulse signal is shifted by a quarter period (time t15 and time t16). Is output.

  FIG. 7C shows a result obtained by calculating the relationship between the pulse width, the fundamental wave, the second harmonic, and the voltage amplitude of the second harmonic. As the pulse width is reduced, the ratio of harmonics to the fundamental wave increases. FIG. 7D shows the relationship between the pulse width and the voltage amplitude ratio between the harmonic and the fundamental wave. The voltage amplitude ratio here is the voltage amplitude of the second harmonic and the third harmonic. It is a value obtained by dividing the average value by the voltage amplitude of the fundamental wave. When the pulse width is 25% or less, since the voltage amplitude ratio of the harmonic to the fundamental wave is 50% or more, it can be seen that the influence of the harmonic is large.

  FIG. 8 is a diagram for explaining the gain and phase delay of the open loop characteristic when the vibration type actuator 10 is driven by the control device 140 and the conventional control device, respectively. FIGS. 8A and 8B show the results (frequency response) of the gain and the phase delay of the open loop characteristic when the speed of the driven body 11 is controlled by changing the pulse width by the control device 140. It is shown. Here, the temporal phase difference of the sine wave drive voltage applied to the piezoelectric element 14 of the vibration type actuator 10 is 90 degrees (a change in amplitude includes a quarter cycle shift). It can be seen that as the pulse width of the AC signal generated by the AC signal generation unit 111 is lowered from 50%, the high-frequency peak near 120 Hz is reduced and the phase delay is improved, and the pulse width is 25% or less. It can be seen that a large improvement effect can be obtained. From this result, in this embodiment, by reducing the pulse width so as to increase the ratio of harmonics, the effect of reducing the mechanical resonance peak can be obtained, and furthermore, good response characteristics with little phase delay can be obtained. It turns out that it is obtained. The reason why the gain is reduced when the pulse width is reduced is that the amplitude of the fundamental wave of the AC voltage is reduced and the speed of the driven body 11 is reduced.

  FIGS. 8C and 8D show the results of gain and phase delay when the speed of the driven body 11 of the vibration type actuator 10 is controlled by a conventional control device. Here, the pulse width of the AC signal for generating the drive voltage is fixed to 50%, and the temporal phase difference of the sin wave drive voltage applied to the piezoelectric element 14 of the vibration actuator 10 is 10 degrees to 90 degrees. The range has been changed. Thereby, the frequency responsiveness by the difference in the ellipticity ratio which arises in the projection part 12 of the vibrating body 15 can be compared. As for the gain, as shown in FIG. 8C, the peak near 120 Hz tends to decrease as the phase difference decreases, but this peak shifts to the high frequency side. That is, the mode of occurrence of peaks in the high frequency range differs depending on the amplitude ratio of the push-up vibration and the feed vibration. Regarding the phase lag, as shown in FIG. 8D, it can be seen that the phase lag increases as the phase difference increases. Therefore, when the conventional phase difference control is performed with the pulse width set to 50%, it is easily affected by the peak appearing in the high frequency region when the driven body 11 is stopped or driven at a low speed, and the controllability is lowered. On the other hand, as described above, in the drive control of the vibration type actuator 10 by the control device 140, the pulse width is set to a value smaller than 50% (for example, 25%) in the high frequency region. The occurrence of problems can be avoided.

  8E and 8F, the temporal phase of the sin wave driving voltage applied to the piezoelectric element 14 of the vibration type actuator 10 is changed in the range of 10 degrees to 90 degrees, and the driven body 11 The results of gain and phase delay when the speed is controlled by the control device 140 are shown. Here, the pulse width of the AC signal generated by the AC signal generator 111 is fixed at 25%. In this case, as shown in FIG. 8 (e), in the gain, it can be seen that no peak occurs in the high frequency region (near 120 Hz) at any phase difference. Further, with respect to the phase delay, as shown in FIG. 8F, it can be seen that the effect of the phase difference on the change in the phase delay is small and good characteristics are obtained. In other words, by setting the pulse width to 25% during stop and low speed driving as in this embodiment, it is possible to suppress the peak from appearing in the high frequency range without stopping the controllability. It can be seen that low-speed driving can be performed. As will be described later, such an effect cannot be obtained simply by lowering the driving voltage applied to the piezoelectric element 14, but by changing the voltage amplitude ratio of the harmonic to the fundamental by controlling the pulse width. Can be obtained for the first time.

  FIG. 9 is a diagram showing a drive current waveform corresponding to the feed vibration and the frequency analysis result when the vibration type actuator 10 is driven by the control device 140. In FIG. 9A, the drive current waveform corresponding to the feed vibration when the drive frequency is 92 kHz and the pulse width of the AC signal generated by the AC signal generation unit 111 is 25% or 50% is compared. ing. Here, the drive current corresponding to the feed vibration is the capacitance current of the piezoelectric element 14 based on the difference between the drive current of one electrode (A phase) of the piezoelectric element 14 and the drive current of the other electrode (B phase). Calculated by subtracting. The harmonic distortion is large in the drive current waveform corresponding to the feed vibration when the pulse width is 50%, whereas the harmonic distortion is small in the drive current waveform corresponding to the feed vibration when the pulse width is 25%. ing. FIG. 9B shows the frequency analysis result of the drive current corresponding to the feed vibration when the pulse width of the AC signal generated by the AC signal generation unit 111 is 25% and 50%, respectively. . When the pulse width is 50%, the harmonic component is large, especially the triple harmonic component is large. However, when the pulse width is 25%, the harmonic component is reduced. Recognize. From this, when the pulse width is 25%, it is considered that the harmonic vibration is similarly reduced in the elliptical vibration of the protrusion 12.

  The harmonic component contained in the rectangular pulse wave that is an AC signal generated by the AC signal generation unit 111 is larger when the pulse width is 25% than when the pulse width is 50%. However, the result shown in FIG. 9 indicates that the harmonic component contained in the feed vibration generated in the vibrating body 15 can be reduced by driving using a rectangular pulse wave having a large harmonic component. As a result, in the drive using a rectangular pulse wave having a large harmonic component, the phase relationship between the feed vibration generated in the vibrating body 15 and the push-up vibration is compensated by the harmonic, and the contact state in which the vibration of the harmonic component hardly occurs reversely. It is thought that has changed. That is, the protrusion 12 of the vibrating body 15 changes its contact state due to the reaction force received from the driven body 11 during driving and the fine unevenness of the contact surface, and the phase relationship between the feed vibration and the thrust vibration is particularly high. Although it is easy to change, it is considered that the phase relationship is compensated by the action of harmonics. In addition, it is desirable that the protrusion 12 of the vibrating body 15 does not generate harmonic vibration as much as possible. Therefore, it is possible to stabilize the vibration state by reducing the pulse width and reducing the harmonic vibration, and it is possible to drive the vibration type actuator 10 less susceptible to mechanical load fluctuations and disturbances. Become.

  FIG. 10 is a diagram illustrating a closed loop characteristic and an open loop characteristic when position feedback control is performed on the vibration actuator 10 by the control device 140. Here, the position feedback control is performed while changing the command frequency in the range of 10 Hz to 300 Hz with the amplitude of the command value generated by the command value generating unit 101 being ± 50 μm. In the phase difference control, the pulse width of the AC signal generated by the AC signal generation unit 111 is set to 14%, and in the frequency control, the pulse width is changed in the range of 14% to 50% according to the operation amount of the drive frequency. This is shown as an example. For comparison, the results of performing phase difference control and frequency control with the pulse width fixed at 50% are also shown in FIG. 10 as a conventional example.

  FIG. 10A shows the relationship between the gain and the frequency of the closed loop characteristic. In the conventional example, a resonance peak exceeding 0 dB is observed in the vicinity of 120 Hz, but in the example, the peak is greatly reduced, and it can be seen that a reduction effect of about 10 dB is obtained. FIG. 10B shows the relationship between the phase delay of the closed loop characteristic and the frequency. Compared to the conventional example, the embodiment shows an improvement in the phase delay in the vicinity of 120 Hz. FIG. 10C shows the relationship between the gain and frequency of the open loop characteristic. It can be seen that the gain in the low frequency region (for example, near 10 Hz) is larger in the embodiment than in the conventional example, and the gain in the high frequency region (for example, near 120 Hz) is reduced. Therefore, in the embodiment, the control gain can be made larger than in the conventional example. FIG. 10 (d) shows the relationship between the phase delay of the open loop characteristic and the drive frequency, and it can be seen that the phase delay is also improved in the embodiment. Thus, by using the control method of the embodiment, it is possible to afford the setting conditions of various parameters used for control, and the resonance peak on the high frequency region side can be greatly reduced without narrowing the control band. Controllability can be improved.

  FIG. 11 is a diagram illustrating a result of positioning control during autofocus driving with a camera by each of the control device 140 and a conventional control device. FIG. 11A shows the result of positioning performed by performing phase difference control and frequency control with a pulse width of an AC signal for generating a drive voltage fixed to 50% by a conventional control device (comparison). Example). In FIG. 11B, the control device 140 performs phase difference control with a pulse width of 20%, and performs frequency control while changing the pulse width in the range of 20% to 50% according to the operation amount of the drive frequency. The result (Example) of having performed positioning by is shown. The autofocus lens is connected to the driven body 11 of the vibration type actuator 10, and the actual position of the autofocus lens is detected using a position sensor (optical sensor) provided in the camera. That is, instead of detecting the position of the driven body 11 of the vibration type actuator 10, the position of the autofocus lens is detected.

  In each of FIGS. 11A and 11B, time is plotted on the horizontal axis and position is plotted on the vertical axis, and the command value and the actual lens position are plotted. In the conventional example shown in FIG. 11A, ringing of about 50 μm occurs in the deceleration region and the stop region, which is considered to be affected by the resonance peak on the high frequency region side. On the other hand, in the example, the occurrence of ringing in the deceleration region and the stop region is suppressed, and it can be seen that better controllability is obtained compared to the conventional example. In the embodiment, the control gain in the frequency control is lower than the control gain in the phase difference control, so that the range of setting conditions of various parameters used for control can be expanded without lowering the maximum speed. . Furthermore, in the frequency control in the embodiment, since the ellipticity ratio is changed without changing the ellipticity ratio generated in the protrusion 12 of the vibrating body 15, the influence of the peak in the high frequency region can be avoided.

  FIG. 12 shows the gain and phase of the open loop characteristic when the drive control of the vibration type actuator 10 is performed by fixing the pulse width of the AC signal for generating the drive voltage to 50% and changing the voltage or the drive frequency. It is a figure explaining each result (frequency responsiveness) of delay. The result shown in FIG. 12 is a comparative example for the present invention, and the sin wave drive voltage applied to the piezoelectric element 14 of the vibration type actuator 10 over time is similar to the conditions for obtaining the result shown in FIG. The phase difference is set to 90 degrees.

  12A and 12B show the open loop characteristics when the driving frequency is 92 kHz, the power supply voltage (voltage of the power supply 161) is 3.0 V and 2.0 V, respectively, and the speed of the driven body 11 is controlled. Gain and phase lag results are shown. Since the power supply voltage is lowered, the voltage applied to the piezoelectric element 14 is reduced to about 67%. When the voltage amplitude is lowered, the amplitude of the elliptical vibration generated in the protrusion 12 of the vibrating body 15 is small. Become. However, as seen in FIG. 12A, a peak occurs in the vicinity of 120 Hz, and the phase delay is not improved as seen in FIG. 12B. Thus, the effect which the said Example show | plays cannot be acquired only by reducing a drive voltage.

  12C and 12D show the gain of the open loop characteristic when the power supply voltage is set to 3.0 V, the speed of the driven body 11 is controlled by changing the drive frequency in the range of 93 kHz to 96 kHz. The result of phase delay is shown. Increasing the drive frequency means moving away from the resonance frequency of the vibrating body 15, so that the amplitude of elliptical vibration generated in the protrusion 12 of the vibrating body 15 is reduced. However, as seen in FIG. 12C, a peak occurs in the vicinity of 120 Hz, and the phase delay is not improved as seen in FIG. Thus, the effect which the said Example show | plays cannot be acquired only by adjusting a drive frequency.

  As described above, in the present embodiment, in the drive control of the vibration type actuator 10, the phase difference control in the high frequency region is used during low speed driving, and the frequency control is used during high speed driving. At this time, by setting the pulse width small in the phase difference control and changing the pulse width in accordance with the driving frequency in the frequency control, the mechanical resonance peak can be reduced and the phase delay can be improved. Thus, good controllability can be obtained without causing a reduction in speed.

  Next, an electronic device to which the vibration type driving device 150 is applied will be described. FIG. 13 is a perspective view showing a schematic configuration of a lens driving mechanism 700 to which the vibration type driving device 150 is applied. The lens driving mechanism 700 includes a vibrating body 701, a lens holding member 702, a first guide bar 703, a second guide bar 704, a pressure magnet 705, and a lens 706. The vibrating body 701 corresponds to the vibrating body 15 shown in FIG. 2, and the second guide bar 704 corresponds to the driven body 11 shown in FIG. In FIG. 13, the control device 140 is not shown.

  The first guide bar 703 and the second guide bar 704 are held by a base (not shown) so as to be parallel to each other and so that the longitudinal direction thereof is parallel to the optical axis direction of the lens 706. The lens holding member 702 includes a cylindrical holder portion 702a that holds the lens 706, a holding portion 702b that holds the vibrating body 701 and the pressing magnet 705, and a guide portion 702c through which the first guide bar 703 is inserted. A first guide portion is formed by inserting a guide portion 702c through the first guide bar 703 so as to be movable.

  A magnetic circuit is formed between the pressure magnet 705, which is a permanent magnet, and the second guide bar 704, and an attractive force is generated between these members, whereby the pressure magnet 705, the second guide bar 704, The vibrating body 701 disposed between the two is pressed against the second guide bar 704. As a result, the two protrusions (corresponding to the protrusion 12 of the vibration member 15 in FIG. 2) of the vibration member are brought into pressure contact with the second guide bar 704 to form the second guide portion. In addition, since the second guide portion forms a guide mechanism using magnetic attraction, when the external force is received, the vibrating body 701 and the second guide bar 704 are separated from each other. It is expected that. As a countermeasure, in the lens driving mechanism 700, the lens holding member 702 (vibrating body 701) returns to a predetermined position by the drop-off preventing portion 702d provided on the lens holding member 702 coming into contact with the second guide bar 704. It is configured.

  When a predetermined drive voltage is supplied from the control device 140 (not shown) to the vibrating body 701, the vibrating body 701 frictionally drives the second guide bar 704, whereby the lens holding member 702 is driven in the optical axis direction of the lens 706. Is done. Here, the lens driving mechanism 700 in which the vibrating body 701 moves in the optical axis direction together with the lens holding member 702 is taken up. However, the lens driving mechanism is configured such that the holding member holding the lens with respect to the fixed vibrating body is covered. The driving body may be configured to move in the optical axis direction.

  Next, an example in which the vibration type driving device 150 is applied to an image blur correction mechanism in an imaging device such as a single-lens reflex camera will be described. FIG. 14A is a plan view (top view) showing the appearance of the imaging apparatus 800. FIG. FIG. 14B is a diagram illustrating a schematic structure inside the imaging apparatus 800. The imaging apparatus 800 generally includes a main body 810 and a lens barrel 820 that can be attached to and detached from the main body 810. The main body 810 includes an image pickup device 830 such as a CCD sensor or a CMOS sensor that converts an optical image formed by the light passing through the lens barrel 820 into an image signal, and a camera control microcomputer that controls the overall operation of the image pickup apparatus 800. 840. The main body 810 is provided with a control device 140 that operates under the control of the camera control microcomputer 840.

  In the lens barrel 820, a plurality of lenses L such as a focus lens and a zoom lens are arranged at predetermined positions. The lens barrel 820 incorporates an image blur correction device 850. The image blur correction device 850 includes a disk member 851, a driven member 11 provided on the disk member 851, and a disk. An image blur correction lens 852 is disposed in a hole formed in the center of the member 851. The image blur correction device 850 is arranged so that the image blur correction lens 852 can be moved in a plane orthogonal to the optical axis of the lens barrel 820 (a chain line in FIG. 14B).

  By driving the vibrating body 15 by the control device 140, the driven body 11 and the disk member 851 move relative to the vibrating body 15 fixed to the lens barrel 820 within a plane orthogonal to the optical axis. The correction lens 852 is driven. Here, the image blur correction apparatus that drives the correction lens 852 has been described. However, the present invention is not limited to this, and the image blur correction apparatus may be configured by driving the image sensor 830 in a direction parallel to the imaging plane. it can. Further, by fixing the vibrating body 15 to the disk member 851 and fixing the driven body 11 to the lens barrel 820, the vibrating body 15 and the disk member 851 move relatively in a plane orthogonal to the optical axis, The correction lens 852 may be driven.

  An example in which the vibration type driving device 150 is applied to positioning of a stage on which an observation object is placed in a positioning stage device will be described. FIG. 15 is an external perspective view of a microscope 900 including the vibration type driving device 150. The microscope 900 includes an imaging unit 930 including an imaging element and an optical system, and an automatic stage unit 910 having a stage 920 that can be moved in an XY plane on a base.

  The control device 140 constituting the vibration type driving device 150 is disposed on the base plate 940, but is not limited thereto, and may be provided in the imaging unit 930, for example. At least two vibrating bodies 15 constituting the vibration type actuator 10 (not shown) are used. At least one vibrating body 15 is used for driving the stage 920 corresponding to the driven body 11 in the X direction, and is arranged so that the X direction of the vibrating body 15 coincides with the X direction of the stage 920. In addition, at least one other vibrating body 15 is used for Y-direction driving of the stage 920 as a driven body, and is arranged so that the X direction of the vibrating body 15 coincides with the Y direction of the stage 920.

  When the observation object is placed on the upper surface of the stage 920 and an enlarged image is captured by the imaging unit 930, when the observation range becomes wide, the automatic stage unit 910 is driven to move the stage 920 in the X direction and the Y direction. Move the object to be observed. As a result, a large number of captured images are captured, and the captured images are combined by image processing with a computer (not shown), thereby obtaining a single image with a wide observation range and high definition.

  The imaging device and the positioning stage device to which the vibration type driving device 150 is applied have been described with reference to FIGS. 13 to 15, but specific application examples of the vibration type driving device 150 are not limited to these. Absent. The vibration type driving device 150 can be widely applied to electronic devices including components that require positioning by driving the vibration type actuator 10.

  Although the present invention has been described in detail based on preferred embodiments thereof, the present invention is not limited to these specific embodiments, and various forms within the scope of the present invention are also included in the present invention. included. For example, in the above embodiment, the vibration body 15 is fixed and the driven body 11 is moved as a moving body. Conversely, the driven body 11 is fixed and the vibration body 15 is moved as a moving body. Even the configuration does not change the effect. Further, the command value generation unit 101 obtains the command value related to the position of the driven body 11 based on the position signal 141 from the position detection unit 145, but is not limited thereto, and detects the speed of the driven body 11. Alternatively, it may be obtained from the detected speed. As long as the control part 120 and the drive part 130 can implement | achieve the function mentioned above, the structure (the electronic device and electric component currently used) is not limited. Further, as the control device 140, the configuration of the two-phase drive in which the piezoelectric element 14 is driven in two phases is taken up. However, the present invention is not limited to the two-phase drive vibration type actuator, and more than three phases are used. The present invention can also be applied to a vibration type actuator that is driven by a plurality of AC voltages.

  The present invention supplies a program that realizes one or more functions of the above-described embodiments to a system or apparatus via a network or a storage medium, and one or more processors in a computer of the system or apparatus read the program. It can also be realized by processing to be executed. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

DESCRIPTION OF SYMBOLS 10 Vibration type actuator 11 Driven body 14 Piezoelectric element 15 Vibrating body 102 Control amount calculation part 106 Determination part (Phase difference-frequency determination part)
Reference Signs List 107 pulse width adjustment unit 111 AC signal generation unit 120 control unit 130 drive unit 140 control unit 145 position detection unit 150 vibration type drive unit 165 pulse signal generation unit 700 lens drive mechanism 800 imaging device 900 microscope

Claims (13)

A vibration type actuator having a vibrating body in which an electro-mechanical energy conversion element and an elastic body are joined, and a driven body in pressure contact with the vibrating body;
A control device for controlling the driving of the vibration type actuator,
A vibration type driving device in which the vibration body and the driven body move relatively by vibration excited by the vibration body by applying a plurality of AC voltages to the electro-mechanical energy conversion element by the control device. Because
The controller is
Generating means for generating the AC voltage based on a pulse signal whose pulse width varies between a first pulse width and a second pulse width greater than the first pulse width;
Control means for feedback-controlling the relative position or speed of the vibrating body and the driven body using the phase difference and frequency of the plurality of AC voltages as operation parameters;
The control means operates the phase difference by fixing the pulse width of the pulse signal to the first pulse width when the vibration actuator is stopped and driven at low speed, and at the time of high speed driving of the vibration actuator, A vibration type driving device characterized in that the pulse width of the pulse signal is changed in the range from the first pulse width to the second pulse width and the frequency is manipulated.   The pulse signal having the first pulse width has a ratio of the second harmonic or the third harmonic to the fundamental wave larger than that of the pulse signal having the second pulse width. Vibration type drive device. The pulse signal is a rectangular wave,
3. The vibration type driving device according to claim 1, wherein the pulse signal having the first pulse width has a duty ratio of 25% or less. 4.   2. The control means according to claim 1, wherein the control gain when the pulse width of the pulse signal is the first pulse width is larger than the control gain when the second pulse width is used. 4. The vibration type driving device according to any one of items 1 to 3.   5. The vibration type driving apparatus according to claim 1, wherein the control unit increases a control gain of a phase difference more than a control gain of a frequency of the plurality of AC voltages. A vibration type actuator having a vibrating body in which an electro-mechanical energy conversion element and an elastic body are joined, and a driven body in pressure contact with the vibrating body;
A control device for controlling the driving of the vibration type actuator,
A vibration type driving device in which the vibration body and the driven body move relatively by vibration excited by the vibration body by applying a plurality of AC voltages to the electro-mechanical energy conversion element by the control device. Because
The controller is
Generating means for generating the AC voltage based on a first pulse signal and a second pulse signal having different harmonic ratios relative to the fundamental wave;
Control means for feedback-controlling the relative position or speed of the vibrating body and the driven body using the phase difference and frequency of the plurality of AC voltages as operation parameters;
The first pulse signal has a higher ratio of harmonics to the fundamental than the second pulse signal,
The control means uses the first pulse signal and operates the phase difference when the vibration actuator is stopped and driven at a low speed, and operates the phase difference between the first pulse signal and the vibration actuator when the vibration actuator is driven at a high speed. A vibration type driving apparatus characterized by using a pulse signal whose harmonic ratio is changed in the range of the second pulse signal and operating the frequency thereof.   The vibration type driving apparatus according to claim 6, wherein the harmonic is a second harmonic or a third harmonic.   8. The vibration type driving device according to claim 6, wherein a ratio of a harmonic to a fundamental wave in the first pulse signal is 50% or more.   The vibration excited by the vibrating body includes a pushing-up vibration in a pressurizing direction that pressurizes and contacts the vibrating body and the driven body, and a feed vibration in a direction orthogonal to the pressurizing direction. The vibration type driving device according to claim 1, wherein the vibration type driving device is a vibration type driving device.   10. The vibration type driving device according to claim 1, further comprising a position detecting unit configured to detect a relative position between the vibrating body and the driven body. A control method for a vibration type actuator comprising: a vibrating body in which an electromechanical energy conversion element and an elastic body are joined; and a driven body in pressure contact with the vibrating body,
A driving step of moving one of the vibrating body and the driven body relative to the other as a moving body by vibration excited on the vibrating body by applying a plurality of alternating voltages to the electromechanical energy conversion element When,
A detecting step for detecting the position of the moving body;
And a control step for feedback control of the position or speed of the moving body in the driving step based on the phase difference and frequency of the plurality of AC voltages based on the position of the moving body detected in the detecting step. And
In the control step, the AC voltage is generated based on a pulse signal whose pulse width changes in a range of a first pulse width and a second pulse width larger than the first pulse width, and the vibration actuator When stopping and driving at low speed, the pulse width of the pulse signal is fixed to the first pulse width and the phase difference is manipulated. When driving the vibration actuator at high speed, the pulse width of the pulse signal is set to the first pulse width. A control method for a vibration type actuator, wherein the frequency is changed within the range of the pulse width of the second pulse width and the frequency is manipulated. A control method for a vibration type actuator comprising: a vibrating body in which an electromechanical energy conversion element and an elastic body are joined; and a driven body in pressure contact with the vibrating body,
A driving step of moving one of the vibrating body and the driven body relative to the other as a moving body by vibration excited on the vibrating body by applying a plurality of alternating voltages to the electromechanical energy conversion element When,
A detecting step for detecting the position of the moving body;
And a control step for feedback control of the position or speed of the moving body in the driving step based on the phase difference and frequency of the plurality of AC voltages based on the position of the moving body detected in the detecting step. And
In the control step, the AC voltage is generated based on a first pulse signal and a second pulse signal in which a ratio of harmonics to a fundamental wave is smaller than the first pulse signal, and the vibration type actuator is stopped. When driving at low speed, the first pulse signal is used and the phase difference is manipulated. When the vibration actuator is driven at high speed, harmonics are generated in the range of the first pulse signal and the second pulse signal. A control method of a vibration type actuator characterized by using a pulse signal with a changed ratio and operating the frequency thereof. A vibration type driving device according to any one of claims 1 to 10,
An electronic device comprising: a component positioned by driving of a vibration type actuator included in the vibration type driving device.