Drive control device and ultrasonic motor system

Abstract

The present invention provides a drive control device capable of easily advancing miniaturization of an ultrasonic motor element. A drive control device (2) that vibrates a vibrating body (4) by applying signals of mutually different phases to a plurality of electrodes provided to a piezoelectric element on the vibrating body (4) is provided with: a signal application section (17) that selectively applies signals to electrodes of a portion of the plurality of electrodes; an amplitude detection section (15) (feedback signal reception section) that receives a feedback signal from an electrode of the plurality of electrodes that is different from the electrode to which the signal application section (17) selectively applies signals; and a signal condition control section (16) that controls a signal condition of the signals applied by the signal application section (17) based on the feedback signal.

Description

Technical Field

[0001] The present invention relates to a drive control device for driving a drive body having a piezoelectric element and an ultrasonic motor system having a piezoelectric element. Background Technology

[0002] Previously, various ultrasonic motors have been proposed that vibrate the stator using piezoelectric elements. For example, an ultrasonic motor has: a stator containing multiple piezoelectric elements polarized; and a rotor in contact with the stator. The stator vibrates by applying signals of different phases to the multiple piezoelectric elements. The rotor rotates due to this vibration.

[0003] The optimal frequency of the signal applied to the piezoelectric element varies depending on the contact pressure of the stator and rotor, the temperature of the ultrasonic motor, and the load applied to the ultrasonic motor. Therefore, by performing appropriate feedback control on the frequency of the aforementioned signal, the ultrasonic motor can be driven effectively.

[0004] In the ultrasonic motor described in Patent Document 1 below, a piezoelectric element and a feedback piezoelectric element are adhered to an elastomer. A feedback signal is output from the feedback piezoelectric element based on the vibration of the elastomer. The driving voltage signal applied to the piezoelectric element is controlled based on the feedback signal.

[0005] Prior art literature

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent No. 2683237 Summary of the Invention

[0008] The problem the invention aims to solve

[0009] In the ultrasonic motor described in Patent Document 1, a piezoelectric element for feedback needs to be placed in the elastomer. Therefore, it is difficult to reduce the number of parts and to make the ultrasonic motor smaller.

[0010] The object of the present invention is to provide a drive control device that can easily drive a miniaturized ultrasonic motor component, and an ultrasonic motor system using the drive control device.

[0011] Technical solutions for solving the problem

[0012] The drive control device of the present invention causes the vibrator to vibrate by applying signals with different phases to a plurality of electrodes provided on a piezoelectric element on the vibrator. The drive control device comprises: a signal application unit that selectively applies signals to a portion of the plurality of electrodes; a feedback signal receiving unit that receives feedback signals from an electrode of the plurality of electrodes that is different from the electrode selectively applied by the signal application unit; and a signal condition control unit that controls the signal conditions applied by the signal application unit based on the feedback signals.

[0013] The ultrasonic motor system of the present invention includes a drive control device configured according to the present invention, the vibrating body, and the plurality of electrodes provided on the piezoelectric element on the vibrating body, but does not have a feedback electrode.

[0014] Invention Effects

[0015] According to the drive control device of the present invention, miniaturization of ultrasonic motor components can be easily achieved. Furthermore, according to the ultrasonic motor system of the present invention, miniaturization can be easily achieved. Attached Figure Description

[0016] Figure 1 This is a connection diagram of the ultrasonic motor components and their drive control circuit in the first embodiment of the present invention.

[0017] Figure 2 This is a schematic control circuit diagram of an ultrasonic motor system according to the first embodiment of the present invention.

[0018] Figure 3 This is a bottom view of the stator in the first embodiment of the present invention.

[0019] Figure 4 This is a front sectional view of the first piezoelectric element in the first embodiment of the present invention.

[0020] Figure 5 This is a flowchart illustrating the operation process of the drive control device in the first embodiment of the present invention.

[0021] Figure 6 This is a graph illustrating an example of the relationship between frequency and feedback voltage.

[0022] Figure 7 (a)~ Figure 7 (c) is a schematic bottom view of the stator used to explain traveling waves in a simple and easy-to-understand way.

[0023] Figure 8 This is a schematic control circuit diagram of an ultrasonic motor system according to a first variation of the first embodiment of the present invention.

[0024] Figure 9 This is a schematic control circuit diagram of an ultrasonic motor system according to a second variation of the first embodiment of the present invention.

[0025] Figure 10 This is a schematic control circuit diagram of an ultrasonic motor system according to the second embodiment of the present invention.

[0026] Figure 11 This is a schematic control circuit diagram of an ultrasonic motor system according to a variation of the second embodiment of the present invention.

[0027] Figure 12 This is a schematic control circuit diagram of an ultrasonic motor system according to the third embodiment of the present invention.

[0028] Figure 13 This is a schematic control circuit diagram of an ultrasonic motor system according to a variation of the third embodiment of the present invention. Detailed Implementation

[0029] Hereinafter, specific embodiments of the present invention will be described with reference to the accompanying drawings, thereby clarifying the present invention.

[0030] In addition, it should be noted that the embodiments described in this specification are illustrative and that partial substitutions or combinations of structures can be made between different embodiments.

[0031] Figure 1 This is a connection diagram of the ultrasonic motor components and their drive control circuit in the first embodiment of the present invention.

[0032] The ultrasonic motor system 1 includes a drive control device 2 and an ultrasonic motor element. The ultrasonic motor element has a stator 3 and a rotor 8. In the ultrasonic motor system 1, a drive signal is applied to the stator 3 from the drive control device 2. As a result, the stator 3 vibrates, generating a traveling wave that revolves around the axis Z. Here, the stator 3 and the rotor 8 are in contact. The rotor 8 is rotated by the traveling wave generated in the stator 3. The specific structure of the ultrasonic motor system 1 will be described below.

[0033] like Figure 1As shown, the stator 3 has a vibrating body 4. The vibrating body 4 is in the shape of a circular plate. The vibrating body 4 has a first main surface 4a and a second main surface 4b. The first main surface 4a and the second main surface 4b are opposite to each other. In this specification, the axis Z refers to the direction connecting the first main surface 4a and the second main surface 4b, and is along the direction of the center of rotation. In addition, the shape of the vibrating body 4 is not limited to a circular plate. The shape of the vibrating body 4 viewed from the axis Z can also be, for example, a regular polygon such as a regular hexagon, a regular octagon, or a regular decagon. The vibrating body 4 contains a suitable metal. However, the vibrating body 4 does not necessarily contain a metal. The vibrating body 4 can also be made of other elastomers such as ceramics, silicon materials, or synthetic resins.

[0034] Here, the piezoelectric element shown in the following embodiments is polarized into multiple piezoelectric elements. For example, one piezoelectric element with a different polarization direction for each region can be listed as a multiple piezoelectric element. Alternatively, multiple piezoelectric elements with different polarization directions can be listed as a multiple piezoelectric element. In the first embodiment, the case where multiple piezoelectric elements are polarized is shown.

[0035] A plurality of piezoelectric elements polarized are disposed on the first principal surface 4a of the vibrating body 4. More specifically, a plurality of piezoelectric elements with different polarization directions are disposed. The second principal surface 4b is in contact with the rotor 8. The rotor 8 has a rotor body 8a and a rotating shaft 8b. The rotor body 8a is in the shape of a circular plate. One end of the rotating shaft 8b is connected to the rotor body 8a. The rotor body 8a is in contact with the second principal surface 4b of the vibrating body 4. In addition, the shape of the rotor body 8a is not limited to a circular plate. The shape of the rotor body 8a viewed from the Z-axis can also be, for example, a regular polygon such as a regular hexagon, a regular octagon, or a regular decagon.

[0036] Signals are applied from the drive control device 2 to the piezoelectric elements, which are polarized into multiple components. This causes the vibrating body 4 of the stator 3 to vibrate. Additionally, the drive control device 2 receives feedback signals from the stator 3. Based on these feedback signals, the drive control device 2 controls the vibration of the stator 3 and the rotational speed of the ultrasonic motor components.

[0037] Figure 2 This is a schematic control circuit diagram of an ultrasonic motor system according to the first embodiment of the present invention.

[0038] The drive control device 2 includes a switching switch 13, a filter unit 14, an amplitude detection unit 15, a signal condition control unit 16, a signal application unit 17, and a switching control unit 18. The filter unit 14, amplitude detection unit 15, and signal condition control unit 16 are sequentially connected between the switching switch 13 and the signal application unit 17. Multiple electrodes are provided on a piezoelectric element that is polarized into multiple electrodes. The switching switch 13 selects the received feedback signal by selecting the connected electrode among the multiple electrodes. The filter unit 14 filters the feedback signal. The amplitude detection unit 15 detects the amplitude of the vibrating body 4 based on the feedback voltage. The amplitude detection unit 15 is the "feedback signal receiving unit" in this invention. The signal condition control unit 16 sets the frequency of the signal applied to each electrode of the piezoelectric element based on the detected amplitude of the vibrating body 4, etc. The signal application unit 17 applies signals to the multiple electrodes. Furthermore, it is possible to selectively apply signals to a subset of the multiple electrodes. More specifically, the signal application unit 17 sends a signal to a selected electrode among the multiple electrodes of the piezoelectric element that is polarized into a plurality of electrodes, causing the piezoelectric element to vibrate. In addition, the switching control unit 18 controls the selection of the electrode of the piezoelectric element connected in the switching switch 13 and the selection of the piezoelectric element that causes it to vibrate in the signal application unit 17.

[0039] Furthermore, the filter unit 14, amplitude detection unit 15, signal condition control unit 16, signal application unit 17, and switching control unit 18 are conceptually divided and described to illustrate their respective functions, but they do not need to be physically separated. For example, the amplitude detection unit 15, signal condition control unit 16, signal application unit 17, and switching control unit 18 may be included in the same microcomputer. In addition, the filter unit 14 is not limited to being composed of filter circuit components, and may be configured as a digital filter within the microcomputer in the same way as the amplitude detection unit 15, etc.

[0040] The feature of this embodiment is that the ultrasonic motor system 1 has multiple electrodes provided with piezoelectric elements on the vibrating body 4 and a drive control device 2, but does not have a feedback electrode. Furthermore, the feature of this embodiment is that the drive control device 2 has a switching switch 13, a signal application unit 17, and an amplitude detection unit 15. The switching switch 13 switches to connect an electrode different from the electrode selectively applied by the signal application unit 17 and the amplitude detection unit 15. Because the ultrasonic motor system 1 has a drive control device 2, the ultrasonic motor system 1 does not require a piezoelectric element and its electrodes for feedback. Therefore, miniaturization of the ultrasonic motor element can be easily achieved. Hereinafter, this detail will be described together with the details of the structure of this embodiment.

[0041] Figure 3 This is a bottom view of the stator in the first embodiment.

[0042] In this embodiment, the piezoelectric elements polarized into multiple components are a first piezoelectric element 5A, a second piezoelectric element 5B, a third piezoelectric element 5C, and a fourth piezoelectric element 5D. The multiple piezoelectric elements are adhered to the vibrator 4 using an adhesive. For example, epoxy resin, polyethylene resin, etc., can be used as the adhesive.

[0043] Multiple piezoelectric elements, polarized in a plurality, are distributed along the circumferential direction of the traveling wave, thereby generating the traveling wave which circumferentially revolves around an axis parallel to the Z-axis. When viewed from the Z-axis, the first piezoelectric element 5A and the second piezoelectric element 5B are positioned opposite each other across the axis. The third piezoelectric element 5C and the fourth piezoelectric element 5D are also positioned opposite each other across the axis.

[0044] Figure 4 This is a front sectional view of the first piezoelectric element in the first embodiment.

[0045] The first piezoelectric element 5A has a piezoelectric body 6. The piezoelectric body 6 has a third main surface 6a and a fourth main surface 6b. The third main surface 6a and the fourth main surface 6b are opposite to each other. The first piezoelectric element 5A has a first electrode 7A and a second electrode 7B. The piezoelectric body 6 is polarized from the third main surface 6a toward the fourth main surface 6b. The first electrode 7A is provided on the third main surface 6a of the piezoelectric body 6, and the second electrode 7B is provided on the fourth main surface 6b.

[0046] The second piezoelectric element 5B, the third piezoelectric element 5C, and the fourth piezoelectric element 5D are constructed in the same manner as the first piezoelectric element 5A. However, the piezoelectric element 6 in the first piezoelectric element 5A and the piezoelectric element 6 in the second piezoelectric element 5B are polarized in opposite directions. Therefore, when the same signal is applied to the first piezoelectric element 5A and the second piezoelectric element 5B, they vibrate in opposite phases. The piezoelectric element 6 in the third piezoelectric element 5C and the piezoelectric element 6 in the fourth piezoelectric element 5D are also polarized in opposite directions. That is, the multiple first, second, third, and fourth piezoelectric elements 5A, 5B, 5C, and 5D are piezoelectric elements that are polarized in multiple ways.

[0047] Multiple piezoelectric elements, polarized into a plurality of units, are electrically connected to the aforementioned drive control device 2. The drive control device 2 causes the multiple piezoelectric elements to vibrate at different phases. Here, one of the different phases is designated as phase A, and the other as phase B. In this embodiment, the phase difference between phase A and phase B is 90°. Furthermore, one of the phases in phase A that are 180° apart is designated as phase A+, and the other as phase A-. Similarly, one of the phases in phase B that are 180° apart is designated as phase B+, and the other as phase B-. In addition, the following embodiment shows an example of control using only phases A and B, but the technology of the present invention can also be applied to cases where control is performed using three phases: phase A, phase B, and phase C.

[0048] like Figure 2 As shown, the same signal is applied from the drive control device 2 to both the first piezoelectric element 5A and the second piezoelectric element 5B. In this embodiment, the first piezoelectric element 5A vibrates in phase A+, and the second piezoelectric element 5B vibrates in phase A-. Furthermore, different signals are applied to the first piezoelectric element 5A and the third piezoelectric element 5C. Moreover, the same signal is applied to the third piezoelectric element 5C and the fourth piezoelectric element 5D. The third piezoelectric element 5C vibrates in phase B+, and the fourth piezoelectric element 5D vibrates in phase B-. Hereinafter, the piezoelectric element vibrating in phase A will sometimes be referred to as piezoelectric element phase A. The piezoelectric element vibrating in phase B will sometimes be referred to as piezoelectric element phase B.

[0049] Additionally, a signal is applied to the first electrode of the piezoelectric element from the drive control device 2. Therefore, the plurality of first electrodes of the piezoelectric element include an A-phase electrode to which a signal of phase A is applied and a B-phase electrode to which a signal of phase B is applied. The first electrode of phase A of the piezoelectric element is the A-phase electrode, and the first electrode of phase B of the piezoelectric element is the B-phase electrode. However, each second electrode of each piezoelectric element can also be either an A-phase electrode or a B-phase electrode. The drive control device 2... Figure 5 The process shown causes stator 3 to vibrate.

[0050] Figure 5 This is a flowchart illustrating the operation process of the drive control device in the first embodiment. Figure 6 This is a graph illustrating an example of the relationship between frequency and feedback voltage. The feedback voltage is the voltage of the feedback signal.

[0051] like Figure 5 As shown, the operation begins in step S1. In step S2, frequency scanning is performed only on phase A of the piezoelectric element. At this time, the signal application unit 17 is controlled by the switching control unit 18, thereby sending a signal from the signal application unit 17 only to phase A of the piezoelectric element. Furthermore, the switching control unit 18 controls the switching switch 13, thereby connecting the switching switch 13 only to the electrode of phase B of the piezoelectric element. In this way, the switching control unit 18 controls the switching switch 13 and the signal application unit 17, so that the piezoelectric element selected by the switching switch 13 among the multiple piezoelectric elements is different from the piezoelectric element vibrating by the signal application unit 17. As a result, during frequency scanning in phase A of the piezoelectric element, a feedback signal from phase B of the piezoelectric element is received. This feedback signal is filtered by the filter unit 14. Then, the feedback voltage of phase B of the piezoelectric element, corresponding to the frequency of the signal applied to phase A of the piezoelectric element, is measured. From this, the following is derived: Figure 6The relationship between the frequency and the feedback voltage is shown. Furthermore, based on the feedback voltage passing through the filter unit 14, the amplitude of the vibrating body 4 is detected by the amplitude detection unit 15. Based on these relationships and the target voltage, the most suitable frequency for the signal transmitted to phase A of the piezoelectric element is calculated in the signal condition control unit 16.

[0052] Furthermore, the target voltage is specifically a target voltage relative to the feedback voltage. The target voltage is stored in the signal condition control unit 16. The target voltage can also be determined, for example, based on the application of the ultrasonic motor component, the required displacement of the vibrating body 4, the rotational speed of the ultrasonic motor component, etc. Similarly, the most suitable frequency can also be based on, for example... Figure 6 The relationship shown and the target voltage are determined based on the required displacement of the vibrating body 4, the rotational speed of the ultrasonic motor components, etc.

[0053] In step S3, phase A of the piezoelectric element is excited, and the excitation of phase B of the piezoelectric element is stopped. In step S3, similar to step S2, the signal application unit 17 is controlled by the switching control unit 18. More specifically, the signal application unit 17 sends a signal only to phase A of the piezoelectric element. At this time, the signal application unit 17 selects the vibration condition for phase A from the vibration conditions for phases A and B, and applies a signal to the phase A electrode of the piezoelectric element. Furthermore, the frequency of the signal is set in the signal condition control unit 16. The frequency of vibration of each piezoelectric element caused by the signal application unit 17 is controlled by the signal condition control unit 16.

[0054] When selecting the phase condition in the signal application unit 17, i.e., selecting phase A or phase B, the selection can be made under the control of the signal condition control unit 16. However, it is not limited to this; the phase condition can also be selected under the control of the signal application unit 17 itself. In this case, the signal application unit 17 may also have a built-in control unit for selecting the phase. Which phase, phase A or phase B, is applied based on the electrodes of the piezoelectric element to which the signal is applied can also be programmed in the signal application unit 17.

[0055] In step S4, the feedback voltage of phase B of the piezoelectric element is measured. In step S4, similar to step S2, the switching control unit 18 controls the switching switch 13. More specifically, the switching switch 13 is connected only to the phase B electrode of the piezoelectric element. Thus, only the phase B electrode and the amplitude detection unit 15 are connected.

[0056] In step S5, frequency scanning is performed only on phase B of the piezoelectric element. At this time, the signal application unit 17 is controlled by the switching control unit 18, thereby sending a signal from the signal application unit 17 only to phase B of the piezoelectric element. Furthermore, the switching control unit 18 controls the switching switch 13, thereby connecting the switching switch 13 only to the electrode of phase A of the piezoelectric element. Then, during frequency scanning in phase B of the piezoelectric element, the feedback voltage from phase A of the piezoelectric element is measured. Therefore, the optimal frequency of the signal sent to phase A of the piezoelectric element is calculated.

[0057] In step S6, the B phase of the piezoelectric element is excited, and the excitation of the A phase of the piezoelectric element is stopped. In step S6, similar to step S5, the signal application unit 17 is controlled by the switching control unit 18. More specifically, the signal application unit 17 sends a signal only to the B phase of the piezoelectric element. At this time, the signal application unit 17 selects the vibration condition of the B phase from the vibration conditions of the A phase and the B phase, and applies a signal to the B phase electrode of the piezoelectric element.

[0058] In step S7, the feedback voltage of phase A of the piezoelectric element is measured. In step S7, similar to step S5, the switching control unit 18 controls the switching switch 13. More specifically, the switching switch 13 is connected only to the phase A electrode of the piezoelectric element. Thus, only the phase A electrode and the amplitude detection unit 15 are connected.

[0059] In step S8, it is determined whether the lower side of the feedback voltage of piezoelectric element phase A and piezoelectric element phase B is above the target voltage. If the feedback voltage is above the target voltage, proceed to step S9. Otherwise, if the feedback voltage is below the target voltage, return to step S2.

[0060] In step S9, the frequency of the signal applied to the piezoelectric element of the stator 3 is calculated based on the target voltage. Specifically, based on the relationship derived in step S2 or step S5, the amplitude of the vibrating body 4 detected in the amplitude detection unit 15, and the target voltage, the most suitable frequency of the signal applied to phase A or phase B of the piezoelectric element is calculated.

[0061] In step S10, a signal of the most suitable frequency is applied to the piezoelectric element of the stator 3. Here, in step S10, the signal application unit 17 applies signals to both phase A and phase B of the piezoelectric element. Thus, the signal application by the signal application unit 17 is not always selective. Furthermore, the signal application unit 17 applies the phase A signal to the phase A electrode of the phase A piezoelectric element and the phase B signal to the phase B electrode of the phase B piezoelectric element. After step S10 is executed, the process returns to step S2. The drive control device 2 repeats the above operation.

[0062] Alternatively, depending on the application of the ultrasonic motor component, the conditions for returning from step S10 to step S2 can be set separately. Examples of such conditions include situations where the ultrasonic motor component rotates for a certain period of time, or where an anomaly is detected. Alternatively, examples could include situations where a stop signal is applied after step S10 and a certain period of time has elapsed after the stop.

[0063] As described above, the drive control device 2 in this embodiment receives feedback signals from either phase A or phase B of the piezoelectric element. This controls the rotation of the ultrasonic motor element. Therefore, a piezoelectric element for feedback is not required. This facilitates the miniaturization of the ultrasonic motor element. Furthermore, by measuring the feedback voltage of each of the multiple polarized piezoelectric elements, abnormalities in the ultrasonic motor system 1 as a whole can be detected. In addition, by vibrating each piezoelectric element based on the measurement of the feedback voltage, the ultrasonic motor element can be stably controlled for factors such as the contact pressure between the stator 3 and rotor 8, and the temperature of the ultrasonic motor element. Since each piezoelectric element can vibrate efficiently, heat generation from each piezoelectric element can also be suppressed.

[0064] As in this embodiment, the drive control device 2 preferably includes a filter section 14. This allows for more accurate feedback. A low-pass filter is more preferably used for the filter section 14. The passband of the filter section 14 is further preferably a frequency band less than three times the resonant frequency of the piezoelectric elements polarized into a plurality of elements. In these cases, noise can be sufficiently removed, and the relationship between frequency and feedback voltage can be fully understood. Therefore, more accurate feedback is possible.

[0065] Figure 7 (a)~ Figure 7 (c) is a schematic bottom view of the stator used to explain traveling waves in a simple and easy-to-understand way. Additionally, in Figure 7 (a)~ Figure 7 In (c), the gray scale shows that the closer to black, the greater the stress in one direction, and the closer to white, the greater the stress in the other direction.

[0066] In this embodiment, in step S3, excitation is performed in phase A of the piezoelectric element, and excitation in phase B of the piezoelectric element is stopped. At this time, the following occurs: Figure 7 The standing wave X of the three waves shown in (a). On the other hand, in step S6, excitation is performed in phase B of the piezoelectric element, and excitation in phase A of the piezoelectric element is stopped. At this time, as shown in (a), a standing wave X of the three waves is generated. Figure 7 The three-wave standing wave Y shown in (b) is generated by exciting three-wave standing waves X and Y with a 90° phase difference, and then combining the two. Figure 7The traveling wave is shown in (c). Furthermore, although a three-wave example is shown, it is not a limitation. Similarly, in the case of nine waves, two standing waves with a 90° phase difference are excited, and a traveling wave is generated through their combination. As described above, by generating a traveling wave in the circumferential direction in the vibrating body 4, the rotor 8, which is in contact with the second principal surface 4b of the vibrating body 4, will rotate around the axial center Z. Furthermore, in this invention, the structure for generating the traveling wave is not limited to the structure of this embodiment; various conventionally known structures for generating traveling waves can be used.

[0067] Alternatively, friction material can be fixed to the surface of the stator 3 in the rotor body 8a. This increases the frictional force between the vibrating body 4 applied to the stator 3 and the rotor 8.

[0068] In this embodiment, the center of the traveling wave coincides with the center of the stator 3 and the center of the vibrating body 4. However, the center of the traveling wave does not necessarily have to coincide with the center of the stator 3 and the center of the vibrating body 4.

[0069] The switch 13 has an A-phase connection portion 13a, a B-phase connection portion 13c, and a neutral portion 13e. The A-phase connection portion 13a is electrically connected to the electrode of the A-phase piezoelectric element. The B-phase connection portion 13c is electrically connected to the electrode of the B-phase piezoelectric element. The neutral portion 13e is not electrically connected to either the A-phase or B-phase piezoelectric element. By selecting the connection between the switch 13 and the A-phase connection portion 13a or the B-phase connection portion 13c, the switch 13 selects the electrode of the piezoelectric element to be connected. The operation of the drive control device 2 may also include a step of setting the switch 13 to be connected to the neutral portion 13e. In this case, signal imbalances in the ultrasonic motor system 1 can be suppressed.

[0070] In this embodiment, the feedback signal of phase A of the piezoelectric element is simultaneously selected by the switching switch 13. Furthermore, for each phase A of the piezoelectric element, the same signal is simultaneously transmitted by the signal application unit 17. The same applies to phase B of the piezoelectric element. However, this is not a limitation; each piezoelectric element can also be selected independently by the switching switch 13 and the signal application unit 17. An example of this is shown below.

[0071] Figure 8 This is a schematic control circuit diagram of an ultrasonic motor system according to a first variation of the first embodiment. Additionally, in Figure 8 In this diagram, the symbol A+ indicates a piezoelectric element vibrating in phase A+, and A- indicates a piezoelectric element vibrating in phase A-. Similarly, B+ indicates a piezoelectric element vibrating in phase B+, and B- indicates a piezoelectric element vibrating in phase B-. Figure 8 The same applies to subsequent schematic control circuit diagrams.

[0072] In this modified example, the switching switch 23 of the drive control circuit 22A has a first A-phase connection portion 23a, a second A-phase connection portion 23b, a first B-phase connection portion 23c, a second B-phase connection portion 23d, and a neutral portion 13e. The first A-phase connection portion 23a is connected to the electrode of the piezoelectric element that vibrates under A-phase+. The second A-phase connection portion 23b is connected to the electrode of the piezoelectric element that vibrates under A-phase-. The first B-phase connection portion 23c is connected to the electrode of the piezoelectric element that vibrates under B-phase+. The second B-phase connection portion 23d is connected to the electrode of the piezoelectric element that vibrates under B-phase-. Under the control of the switching control unit 18, the switching switch 23 selects the piezoelectric element to be connected by selecting the connection with each of the above-mentioned connection portions.

[0073] The piezoelectric element vibrating under phase A+, phase A-, phase B+, and phase B- is independently connected to the signal application unit 17. Under the control of the switching control unit 18, the signal application unit 17 selects the piezoelectric element that is polarized into a plurality of piezoelectric elements to cause it to vibrate.

[0074] Figure 9 This is a schematic control circuit diagram of an ultrasonic motor system according to a second variation of the first embodiment.

[0075] In this modified example, no switching switch is provided in the drive control circuit 22B. The drive control circuit 22B has a filter section 24A and a filter section 24B. The passband of the filter section 24A is suitable for filtering the signal from phase A of the piezoelectric element. The passband of the filter section 24B is suitable for filtering the signal from phase B of the piezoelectric element. Alternatively, the filter sections 24A and 24B can also be configured as a single unit.

[0076] The switching control unit 18 instructs the amplitude detection unit 15 to switch the electrodes receiving feedback signals, thereby enabling the amplitude detection unit 15 to switch itself. This reduces the number of components, reduces noise caused by the switching switch, and eliminates impedance mismatch between phase A and phase B. In this way, by eliminating the use of a switching switch, the stability of the electrical connection between the piezoelectric element electrodes and the amplitude detection unit 15 can be improved, thus enhancing loop stability.

[0077] In this modified example, for instance, the electrodes of the piezoelectric element are connected to the input / output terminals of a microcomputer including the amplitude detection unit 15. This microcomputer may also include at least two of the following: filter units 24A and 24B of the drive control circuit 22B, the amplitude detection unit 15, the signal condition control unit 16, the signal application unit 17, and the switching control unit 18. When the microcomputer includes filter units 24A and 24B, the filter units 24A and 24B may be digital filters. Preferably, the microcomputer includes all of the filter units 24A and 24B, the amplitude detection unit 15, the signal condition control unit 16, the signal application unit 17, and the switching control unit 18. In this case, the entire drive control circuit 22B can be configured as a single microcomputer. This further reduces the number of components and further reduces noise.

[0078] Figure 10 This is a schematic control circuit diagram of the ultrasonic motor system according to the second embodiment. Figure 10 In the diagram, the piezoelectric element is shown using shaded lines. (This will be discussed later.) Figure 11 The same applies to China.

[0079] The structure of the piezoelectric element 35 connected to the drive control device 2 in this embodiment differs from that in the first embodiment. Apart from the aspects described above, the ultrasonic motor system of this embodiment has the same structure as the ultrasonic motor system 1 of the first embodiment.

[0080] The piezoelectric element 35 is a single piezoelectric element that has been polarized into multiple regions. Details of the piezoelectric element 35 are described below. The piezoelectric element 35 is annular. The piezoelectric element 35 has multiple regions. The piezoelectric element 35 has a different polarization direction for each region. Thus, the piezoelectric element 35 vibrates in different regions at different phases. The multiple regions are arranged in a circumferential direction within the piezoelectric element 35. More specifically, the multiple regions include multiple first A-phase regions, multiple second A-phase regions, multiple first B-phase regions, and multiple second B-phase regions. The piezoelectric element 35 vibrates in the first A-phase regions at A-phase+ and in the second A-phase regions at A-phase-. The piezoelectric element 35 vibrates in the first B-phase regions at B-phase+ and in the second B-phase regions at B-phase-.

[0081] As described above, each region in the piezoelectric element 35 vibrates at different phases. The piezoelectric element 35 includes three of each of the aforementioned regions. Alternatively, the piezoelectric element 35 may include at least one of each of the aforementioned regions.

[0082] The piezoelectric element 35 has a plurality of first electrodes. Each first electrode is arc-shaped. The first electrodes disposed in adjacent regions of the piezoelectric element 35 do not contact each other. In this embodiment, the piezoelectric body of the piezoelectric element 35 is polarized in opposite directions in the first A-phase region and the second A-phase region. Similarly, the piezoelectric body of the piezoelectric element 35 is polarized in opposite directions in the first B-phase region and the second B-phase region. That is, the piezoelectric element 35 is a piezoelectric element that is polarized in multiple ways.

[0083] The A-phase connection portion 13a of the switch 13 in the drive control device 2 is electrically connected to the electrodes of a plurality of first A-phase regions and a plurality of second A-phase regions. On the other hand, the B-phase connection portion 13c is electrically connected to the electrodes of a plurality of first B-phase regions and a plurality of second B-phase regions. Therefore, under the control of the switching control unit 18, the switch 13 selects the electrodes of the region to be connected by selecting the connection with either the A-phase connection portion 13a or the B-phase connection portion 13c.

[0084] Electrodes from multiple first A-phase regions and multiple second A-phase regions are commonly connected to the signal application unit 17. Similarly, multiple first B-phase regions and multiple second B-phase regions are commonly connected to the signal application unit 17. Under the control of the switching control unit 18, the signal application unit 17 selects one of the multiple piezoelectric elements that is polarized to cause it to vibrate.

[0085] In this embodiment, the operation process of the drive control device 2 is also related to... Figure 5 The process is the same. The drive control device 2 receives feedback signals from the first A-phase region and the second A-phase region, or the first B-phase region and the second B-phase region, of the piezoelectric element 35. This controls the rotation of the ultrasonic motor. Therefore, a piezoelectric element for feedback is not required. Thus, similar to the first embodiment, miniaturization of the ultrasonic motor components can be easily achieved.

[0086] Figure 11 This is a schematic control circuit diagram of an ultrasonic motor system according to a variation of the second embodiment.

[0087] In this modified example, the switching switch 23 has the same structure as the first modified example of the first embodiment. The first A-phase connection portion 23a is connected to the electrode of the first A-phase region. The second A-phase connection portion 23b is connected to the electrode of the second A-phase region. The first B-phase connection portion 23c is connected to the electrode of the first B-phase region. The second B-phase connection portion 23d is connected to the electrode of the second B-phase region. Under the control of the switching control unit 18, the switching switch 23 selects the electrode of the region to be connected among the electrodes of the plurality of regions of the piezoelectric element 35 by selecting the connection to each of the above-mentioned connection portions.

[0088] The electrodes of the first A-phase region, the second A-phase region, the first B-phase region, and the second B-phase region are each independently connected to the signal application unit 17. Under the control of the switching control unit 18, the signal application unit 17 selects the region among the multiple regions of the piezoelectric element 35 that causes it to vibrate. In this modified example, similar to the second embodiment, miniaturization of the ultrasonic motor element can be easily promoted.

[0089] Furthermore, the drive control device of the present invention can also be used in ultrasonic linear motors. An example is shown below.

[0090] Figure 12 This is a schematic control circuit diagram of the ultrasonic motor system according to the third embodiment.

[0091] The ultrasonic motor element in the ultrasonic motor system 41 of this embodiment is an ultrasonic linear motor. The ultrasonic motor system 41 has an oscillator 43. The oscillator 43 has a cuboid-shaped vibrating body 44. Multiple piezoelectric elements are disposed on the vibrating body 44. More specifically, the oscillator 43 has two piezoelectric element phases A and two piezoelectric element phases B. Furthermore, one piezoelectric element phase A vibrates at phase A+, and the other piezoelectric element phase A vibrates at phase A-. One piezoelectric element phase B vibrates at phase B+, and the other piezoelectric element phase B vibrates at phase B-.

[0092] exist Figure 12 In the diagram, the symbol A+ represents the piezoelectric element oscillating in phase A+, and the symbol A- represents the piezoelectric element oscillating in phase A-. Furthermore, in... Figure 12 In the diagram, the piezoelectric element phase B vibrating under phase B+ is indicated by the symbol B+, and the piezoelectric element phase B vibrating under phase B- is indicated by the symbol B-. Multiple piezoelectric elements are arranged along the length of the vibrating body 44. Piezoelectric element phases A and B are arranged alternately. More specifically, piezoelectric element phase A vibrating under phase A+, piezoelectric element phase B vibrating under phase B+, piezoelectric element phase A vibrating under phase A-, and piezoelectric element phase B vibrating under phase B- are arranged sequentially.

[0093] The ultrasonic motor system 41 has the same drive control device 2 as in the first embodiment. The A-phase connection portion 13a of the switch 13 in the drive control device 2 is electrically connected to the A-phase electrodes of a plurality of piezoelectric elements. On the other hand, the B-phase connection portion 13c is electrically connected to the B-phase electrodes of a plurality of piezoelectric elements. Therefore, under the control of the switching control unit 18, the switch 13 selects the electrode of the piezoelectric element to be connected by choosing either the connection to the A-phase connection portion 13a or the B-phase connection portion 13c.

[0094] The electrodes of multiple piezoelectric elements in phase A are connected to the signal application unit 17. Similarly, the electrodes of multiple piezoelectric elements in phase B are connected to the signal application unit 17. Under the control of the switching control unit 18, the signal application unit 17 selects the piezoelectric element among the multiple piezoelectric elements to cause it to vibrate.

[0095] In this embodiment, the operation process of the drive control device 2 is also related to... Figure 5 The process shown is the same. The drive control device 2 receives feedback signals from either phase A or phase B of the piezoelectric element. This controls the rotation of the ultrasonic motor. Therefore, the piezoelectric element and its electrodes for feedback are not required. Thus, similar to the first embodiment, miniaturization of the ultrasonic motor components can be easily achieved.

[0096] Figure 13 This is a schematic control circuit diagram of an ultrasonic motor system according to a variation of the third embodiment.

[0097] In this modified example, the switch 23 has the same structure as the first modified example of the first embodiment. The first A-phase connection portion 23a is connected to the electrode of the piezoelectric element phase A, which vibrates under A-phase+. The second A-phase connection portion 23b is connected to the electrode of the piezoelectric element phase A, which vibrates under A-phase-. The first B-phase connection portion 23c is connected to the electrode of the piezoelectric element phase B, which vibrates under B-phase+. The second B-phase connection portion 23d is connected to the electrode of the piezoelectric element phase B, which vibrates under B-phase-. Under the control of the switching control unit 18, the switch 23 selects the electrode of the piezoelectric element to be connected by selecting the connection to each of the above-mentioned connection portions.

[0098] Each piezoelectric element's electrode is independently connected to the signal application unit 17. The signal application unit 17 selects the piezoelectric element to vibrate under the control of the switching control unit 18. In this modified example, similar to the third embodiment, miniaturization of the ultrasonic motor element can be easily achieved.

[0099] Symbol Explanation

[0100] 1...Ultrasonic motor system;

[0101] 2...Drive control device;

[0102] 3...Stator;

[0103] 4...vibrating body;

[0104] 4a, 4b... First and second main faces;

[0105] 5A~5D...First to fourth piezoelectric elements;

[0106] 6...piezoelectric elements;

[0107] 6a, 6b... Third and fourth principal faces;

[0108] 7A, 7B... First and second electrodes;

[0109] 8... rotor;

[0110] 8a...rotor body;

[0111] 8b... Rotation axis;

[0112] 13... toggle switch;

[0113] 13a...A phase connection part;

[0114] 13c...B phase connection;

[0115] 13e... Neutral part;

[0116] 14...Filter section;

[0117] 15...Amplitude detection unit (feedback signal receiving unit);

[0118] 16...Signal Condition Control Unit;

[0119] 17...Signal application section;

[0120] 18...Switching control unit;

[0121] 22A, 22B... drive control circuit;

[0122] 23... toggle switch;

[0123] 23a, 23b... Connection between the first and second A phases;

[0124] 23c, 23d... Connection between the first and second B phases;

[0125] Filter sections 24A, 24B...

[0126] 35... Piezoelectric elements;

[0127] 41...Ultrasonic motor system;

[0128] 43... Oscillator;

[0129] 44... Vibrating body.

Claims

1. A drive control device comprising a plurality of piezoelectric elements on a vibrating body, each having electrodes, wherein the vibrating body is vibrated by applying signals of different phases to the plurality of electrodes, wherein... The drive control device includes: The signal application unit selectively applies a signal to a portion of the plurality of electrodes or applies a signal to all of the plurality of electrodes; The feedback signal receiving unit receives feedback signals from an electrode among the plurality of electrodes that is different from the electrode to which the signal applying unit selectively applied the signal; and The signal condition control unit controls the signal conditions applied by the signal application unit based on the feedback signal. The vibrating body is in the shape of a circular plate. The drive control device also includes a rotor that contacts the vibrating body. The plurality of piezoelectric elements are distributed on the vibrating body to generate a traveling wave. The signal application unit applies a signal to all of the plurality of electrodes based on the control of the signal condition control unit, thereby generating the traveling wave. The signals applied to the plurality of electrodes by the signal application unit include phase A signals and phase B signals. The plurality of electrodes includes an A-phase electrode to which the A-phase signal is applied and a B-phase electrode to which the B-phase signal is applied. When the signal application unit applies the B-phase signal to the B-phase electrode but does not apply a signal to the A-phase electrode, the feedback signal received by the feedback signal receiving unit is the signal from the A-phase electrode.

2. The drive control device according to claim 1, wherein, It also includes a filter section connected between the plurality of electrodes and the feedback signal receiving section, which filters the feedback signal.

3. The drive control device according to claim 1 or 2, wherein, It also includes: a switching control unit that instructs the switching connection of the feedback signal receiving unit, such that an electrode among the plurality of electrodes that is different from the electrode to which the signal applying unit has selectively applied is connected to the feedback signal receiving unit.

4. The drive control device according to claim 1 or 2, wherein, It also includes a switching switch to switch the connection so that an electrode among the plurality of electrodes that is different from the electrode to which the signal application unit selectively applies the signal is connected to the feedback signal receiving unit.

5. The drive control device according to claim 1 or 2, wherein, Repeat the following actions: measure the voltage of the feedback signal; determine whether the voltage of the feedback signal is above the target voltage; set the vibration conditions of the piezoelectric element; and apply a signal to the piezoelectric element.

6. An ultrasonic motor system, comprising: The drive control device according to any one of claims 1 to 5; The vibrating body; and The plurality of electrodes, and the piezoelectric element disposed on the vibrating body. The ultrasonic motor system does not have a feedback electrode.

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