Drive control device and ultrasonic motor system

Abstract

Provided is a drive control device and an ultrasonic motor system that can easily improve rotational efficiency. A drive control device (2) is a drive control device that drives an ultrasonic motor element (1) having a piezoelectric element, and includes: a resistance (R2) for a voltage dividing circuit portion that constitutes, together with a resistance (R1) for identification for identifying the ultrasonic motor element (1), a voltage dividing circuit portion (D); a control circuit portion (15) that is connected to the voltage dividing circuit portion (D) and sets a drive condition of the ultrasonic motor element (1) in accordance with a voltage of an identification signal for identifying the ultrasonic motor element (1); and a drive circuit portion (16) that applies a drive voltage to the piezoelectric element based on the drive condition set by the control circuit portion (15).

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 motor elements that vibrate a stator using piezoelectric elements have been proposed. For example, the ultrasonic motor element described in Patent Document 1 below has a stator including multiple piezoelectric elements and a rotor in contact with the stator. By applying signals of different phases to the multiple piezoelectric elements, the stator is vibrated. This vibration causes the rotor to rotate.

[0003] For example, a signal is input to the ultrasonic motor element using the drive circuit described in Patent Document 2. This drive circuit has two 8-bit D / A converters and a trapezoidal resistor network. The command value for the rotation speed at 16-bit resolution is input separately to the two 8-bit D / A converters. Thus, even if the internal A / D converter of the microcomputer is 8-bit, it is possible to control the rotation speed of the ultrasonic motor element based on 16-bit resolution.

[0004] Prior art literature

[0005] Patent documents

[0006] Patent Document 1: International Publication No. 2010 / 061508

[0007] Patent Document 2: Japanese Patent Application Publication No. 2000-078863 Summary of the Invention

[0008] The problem the invention aims to solve

[0009] 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 element, and the load applied to it. Therefore, it is difficult to improve the rotational efficiency of the ultrasonic motor element when the frequency of the input signal is kept constant. Furthermore, the piezoelectric element or metal component used in the ultrasonic motor element exhibits deviations due to individual differences. Therefore, to improve the rotational efficiency of the ultrasonic motor element, the frequency scanning range needs to be different for each ultrasonic motor element. However, even when using the ultrasonic motor element described in Patent Document 1 or the drive circuit described in Patent Document 2, deviations occur in the frequency scanning time for each ultrasonic motor element when the above-described measures are taken. Therefore, it is difficult to effectively improve the rotational efficiency of the ultrasonic motor element.

[0010] The purpose of this invention is to provide a drive control device and an ultrasonic motor system that can easily improve rotational efficiency.

[0011] means for solving problems

[0012] The drive control device of the present invention is a drive control device for driving an ultrasonic motor element having a piezoelectric element, comprising: a resistor for a voltage divider circuit section, which together with an identification resistor for identifying the ultrasonic motor element constitutes a voltage divider circuit section; a control circuit section connected to the voltage divider circuit section, which sets the drive conditions of the ultrasonic motor element according to the voltage of the identification signal for identifying the ultrasonic motor element; and a drive circuit section that applies a drive voltage to the piezoelectric element based on the drive conditions set by the control circuit section.

[0013] In a broad aspect of the ultrasonic motor system of the present invention, it comprises: a drive control device configured according to the present invention; and the ultrasonic motor element having the piezoelectric element and the identification resistor.

[0014] In another broad aspect of the ultrasonic motor system of the present invention, it comprises: a drive control device configured according to the present invention; and the ultrasonic motor element having a plurality of the piezoelectric elements and a plurality of the identification resistors.

[0015] In another broad aspect of the ultrasonic motor system of the present invention, it comprises: a drive control device configured according to the present invention; and a plurality of the ultrasonic motor elements, each having the piezoelectric element and the identification resistor.

[0016] Invention Effects

[0017] According to the present invention, a drive control device and an ultrasonic motor system that can easily improve rotational efficiency can be provided. Attached Figure Description

[0018] Figure 1 This is a connection diagram of the ultrasonic motor element and its drive control circuit in the first embodiment of the present invention.

[0019] Figure 2 This is a schematic control circuit diagram of the ultrasonic motor system according to the first embodiment of the present invention.

[0020] Figure 3 This is a bottom view of the stator in the first embodiment of the present invention.

[0021] Figure 4 This is a front cross-sectional view of the first piezoelectric element in the first embodiment of the present invention.

[0022] Figure 5 This is a flowchart illustrating the operation process of the drive control device in the first embodiment of the present invention.

[0023] Figure 6 This is a schematic control circuit diagram of an ultrasonic motor system according to a variation of the first embodiment of the present invention.

[0024] Figure 7 (a) to (c) are schematic bottom views for easy understanding of the stator of a traveling wave.

[0025] Figure 8 This is a schematic control circuit diagram of the ultrasonic motor system according to the second embodiment of the present invention.

[0026] Figure 9 This is a flowchart illustrating the operation process of the drive control device in the second embodiment of the present invention.

[0027] Figure 10 This is a schematic control circuit diagram of an ultrasonic motor system according to the third embodiment of the present invention.

[0028] Figure 11 This is a flowchart illustrating the operation process of the drive control device in the third embodiment of the present invention.

[0029] Figure 12 This is a schematic control circuit diagram of an ultrasonic motor system according to a variation of the third embodiment of the present invention.

[0030] Figure 13 This is a schematic control circuit diagram of an ultrasonic motor system according to the fourth embodiment of the present invention. Detailed Implementation

[0031] Hereinafter, specific embodiments of the present invention will be described with reference to the accompanying drawings, thereby making the present invention clear.

[0032] It should be noted that the embodiments described in this specification are illustrative, and it is indicated in advance that partial substitutions or combinations of structures can be made between different embodiments.

[0033] Figure 1 This is a connection diagram of the ultrasonic motor element and its drive control circuit in the first embodiment of the present invention.

[0034] The ultrasonic motor system 10 includes a drive control device 2 and an ultrasonic motor element 1. The ultrasonic motor element 1 includes a stator 3 and a rotor 8. In the ultrasonic motor system 10, a drive signal is applied from the drive control device 2 to the stator 3. As a result, the stator 3 vibrates, generating a traveling wave that revolves around the axis Z. Here, the stator 3 is in contact with the rotor 8. The traveling wave generated in the stator 3 causes the rotor 8 to rotate. The specific structure of the ultrasonic motor system 10 will be described below.

[0035] 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 the direction along the center of rotation. It should be noted that the shape of the vibrating body 4 is not limited to a circular plate. The shape of the vibrating body 4 as 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 includes a suitable metal. However, the vibrating body 4 does not necessarily have to include a metal. The vibrating body 4 can also be made of other elastomers such as ceramics, silicon materials, or synthetic resins.

[0036] Here, the piezoelectric element shown in the following embodiments is polarized into multiple piezoelectric elements. For example, one piezoelectric element may have a different polarization direction for each region. Alternatively, multiple piezoelectric elements with different polarization directions may be used as examples of piezoelectric elements.

[0037] Multiple piezoelectric elements, polarized in multiple ways, are disposed on the first principal surface 4a of the vibrating body 4. Specifically, multiple piezoelectric elements are disposed on the first principal surface 4a. The second principal surface 4b of the vibrating body 4 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. It should be noted that 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 hexagon, a regular octagon, or a regular decagon, etc., a regular polygon.

[0038] Figure 2 This is a schematic control circuit diagram of the ultrasonic motor system according to the first embodiment.

[0039] The ultrasonic motor element 1 has an identification resistor R1 for identifying the ultrasonic motor element. The identification resistor R1 can directly identify the ultrasonic motor element itself. Alternatively, the identification resistor R1 can indirectly identify the ultrasonic motor element by identifying a piezoelectric element. Specifically, the identification resistor R1 can identify a group of piezoelectric elements in the ultrasonic motor element, or it can identify individual piezoelectric elements. In this invention, the identification resistor is set with a resistance value according to each ultrasonic motor element, each group of piezoelectric elements, or each individual piezoelectric element. The ultrasonic motor element 1 is connected to the drive control device 2 via a connector 9. The connector 9 has identification signal wiring 9a and drive signal wiring 9b.

[0040] The drive control device 2 includes a power supply unit 13, a resistor R2 for the voltage divider circuit, an analog-to-digital converter 14, a control circuit 15, and a drive circuit 16. The resistor R2 for the voltage divider circuit, together with the identification resistor R1 of the ultrasonic motor element 1, constitutes the voltage divider circuit D. It should be noted that by using series or parallel connections for the identification resistor R1 and the voltage divider circuit resistor R2, the distribution of deviations in the combined resistance value can be improved.

[0041] More specifically, one end of the resistor R2 in the voltage divider circuit section is connected to the identification resistor R1 and the control circuit section 15. It should be noted that in this embodiment, the resistor R2 in the voltage divider circuit section is indirectly connected to the control circuit section 15 via the analog-to-digital converter 14. However, the analog-to-digital converter 14 may not be necessary. The resistor R2 in the voltage divider circuit section and the identification resistor R1 are connected via the identification signal wiring 9a of the connector 9. The other end of the resistor R2 in the voltage divider circuit section is connected to the power supply section 13. One end of the identification resistor R1 is connected to the resistor R2 in the voltage divider circuit section, and the other end is connected to ground potential. Thus, the voltage divider circuit section D is constructed. It should be noted that in this embodiment, the resistor R2 in the voltage divider circuit section is a bleeder resistor.

[0042] As described above, an analog-to-digital converter 14 is connected between the voltage divider circuit section D and the control circuit section 15. Furthermore, the control circuit section 15 is connected to the drive circuit section 16. The drive circuit section 16 is connected to the drive signal of the connector 9 via wiring 9b. It should be noted that the drive signal wiring 9b is connected to each piezoelectric element of the ultrasonic motor element 1. A drive voltage is applied to each piezoelectric element via the drive circuit section 16.

[0043] An identification signal for identifying the ultrasonic motor element 1 is sent from the voltage divider circuit section D to the control circuit section 15. More specifically, this signal is converted into a digital signal in the analog-to-digital converter section 14. The control circuit section 15 receives this converted signal. Here, the voltage of the identification signal sent from the voltage divider circuit section D is equivalent to a resistive voltage division determined by the resistance values ​​of the identification resistor R1 and the voltage divider circuit section resistor R2. Therefore, by measuring the voltage of the identification signal, the ultrasonic motor element 1 can be identified.

[0044] It should be noted that the power supply unit 13, the voltage divider circuit resistor R2, the analog-to-digital converter 14, the control circuit unit 15, and the drive circuit unit 16 are conceptually described separately to illustrate their respective functions, but they do not need to be physically separated. For example, the power supply unit 13, the voltage divider circuit resistor R2, the analog-to-digital converter 14, the control circuit unit 15, and the drive circuit unit 16 can also be included in the same microcomputer. However, the drive control device 2 may not include the power supply unit 13 and may be connected to an external power source.

[0045] This embodiment is characterized in that the ultrasonic motor element 1 has an identification resistor R1. Furthermore, this embodiment is characterized in that the drive control device 2 has a voltage divider circuit section resistor R2 that, together with the identification resistor R1, constitutes the voltage divider circuit section D, and a control circuit section 15 that sets the drive conditions of the piezoelectric element based on the voltage of the received identification signal. Therefore, frequency scanning suitable for each piezoelectric element can be performed, thus shortening the frequency scanning time and making it difficult for deviations to occur during that time. Therefore, it is easy to easily set the optimal frequency for each piezoelectric element, and the rotational efficiency of the ultrasonic motor element 1 can be easily improved. Hereinafter, these details will be described together with the detailed structure of this embodiment.

[0046] Figure 3 This is a bottom view of the stator in the first embodiment.

[0047] 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 attached to the vibrator 4 using an adhesive. For example, epoxy resin or polyethylene resin can be used as the adhesive.

[0048] Multiple piezoelectric elements, polarized in a plurality, are distributed along the circumferential direction of a traveling wave that surrounds an axis parallel to the Z-axis, thereby generating the traveling wave. When viewed from the Z-axis, the first piezoelectric element 5A and the second piezoelectric element 5B are opposite each other across the axis. The third piezoelectric element 5C and the fourth piezoelectric element 5D are opposite each other across the axis.

[0049] Figure 4 This is a front cross-sectional view of the first piezoelectric element in the first embodiment.

[0050] 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.

[0051] 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 elements 6 in the third piezoelectric element 5C and the fourth piezoelectric element 5D are also polarized in opposite directions. That is, the first piezoelectric element 5A, the second piezoelectric element 5B, the third piezoelectric element 5C, and the fourth piezoelectric element 5D are multiple piezoelectric elements. The multiple piezoelectric elements are electrically connected to the drive control device 2 via the drive signal wiring 9b.

[0052] Here, the resonant frequency of the piezoelectric element varies depending on the individual differences of the piezoelectric body or the thickness of the adhesive bonding the piezoelectric element to the vibrating body. Therefore, in this embodiment, the resonant frequency of each piezoelectric element in the stator 3 is measured. A resistor R1 for identifying the resistance value corresponding to this result is disposed in the ultrasonic motor element 1. In this embodiment, the first piezoelectric element 5A, the second piezoelectric element 5B, the third piezoelectric element 5C, and the fourth piezoelectric element 5D are a group of piezoelectric elements. A resistor R1 for identifying the resistance value corresponding to the above-mentioned group of piezoelectric elements is disposed in the ultrasonic motor element 1. However, multiple identification resistors corresponding to the resonant frequency of each piezoelectric element may also be disposed. The drive control device 2 is controlled by... Figure 5 The flowchart shown illustrates how the piezoelectric element vibrates, causing the stator 3 to vibrate.

[0053] Figure 5 This is a flowchart illustrating the operation process of the drive control device in the first embodiment.

[0054] like Figure 5 As shown, the operation begins in step S1. In step S2, the counter m is set to 0. The counting of the counter m is performed in the control circuit unit 15. More specifically, the control circuit unit 15 includes a measuring unit 15A, a storage unit 15B, and a control unit 15C. The counting of the counter m is performed in the control unit 15C.

[0055] In step S3, the voltage of the identification signal is measured. The identification signal is converted into a digital signal in the analog-to-digital converter 14. The voltage of the converted identification signal is measured in the measuring unit 15A of the control circuit unit 15. However, the measuring unit may be configured separately from the control circuit unit 15. In this case, the control circuit unit 15 may not include the measuring unit 15A.

[0056] In step S4, the counter m is incremented by 1. In step S5, it is determined whether a recognition signal voltage has been output. This determination is performed in the control unit 15C of the control circuit unit 15. If it is determined that no recognition signal voltage has been output, there may be a malfunction in the connection between the ultrasonic motor element 1 and the drive control device 2. In step S5, a check is performed to determine whether there is a malfunction in the connection. If it is determined that no recognition signal voltage has been output, the process proceeds to step T1.

[0057] In step T1, it is determined whether the counter m is less than the set value n. This determination is performed in the control unit 15C of the control circuit unit 15. The value of the set value n can also be arbitrarily set. If it is determined that m < n, the process returns to step S3. Then, in step S3, the voltage of the identification signal is measured again. After that, in step S4, the counter m is incremented by 1, and in step S5, it is determined whether the voltage of the identification signal is output. In this way, the check for any defects in the connection between the ultrasonic motor element 1 and the drive control device 2 is repeated. In step T1, if it is determined that m ≥ n, a connection error is detected. That is, the above check is basically repeated n times in steps S3 to S5, and if it is determined that the voltage of the identification signal is not output in any case, a connection error is detected.

[0058] It should be noted that, Figure 5 A connection error refers to a problem in the connection between the ultrasonic motor component 1 and the drive control device 2. For example, the cause may be a broken connector 9, the connector 9 becoming detached from the ultrasonic motor component 1 or the drive control device 2, or poor contact between the connector 9 and the ultrasonic motor component 1 or the drive control device 2.

[0059] In step S5, if it is determined that a voltage of the identification signal has been output, the process proceeds to step S6. In step S6, it is determined whether the voltage of the identification signal is within a predetermined value. This determination is performed in the control unit 15C of the control circuit unit 15. Specifically, "within the predetermined value" means within a set voltage value range; an upper limit and a lower limit can also be set. In this embodiment, the predetermined value is set for identifying a group of piezoelectric elements. Thus, the ultrasonic motor element 1 having the aforementioned group of piezoelectric elements is identified. The predetermined value is set based on the resistance voltage division determined by the resistance values ​​of the identification resistor R1 and the voltage divider circuit unit resistor R2. It should be noted that when multiple voltage divider circuit units are configured for identifying each piezoelectric element, the predetermined value can also be set for identifying each piezoelectric element. In step S6, if it is determined that the voltage of the identification signal is not within the predetermined value, the process proceeds to step T2.

[0060] In step T2, it is determined whether the counter m is less than the set value n. If m < n, the process returns to step S3. Then, in step S3, the voltage of the identification signal is measured again. After that, in step S4, the counter m is incremented by 1. In step S5, it is determined whether the voltage of the identification signal has been output. Then, in step S6, it is determined again whether the voltage of the identification signal is within the specified value. In this way, the check to determine whether the piezoelectric element is the target piezoelectric element is repeated. In step T2, if m ≥ n, a resistance inconsistency is detected. That is, basically, the above check is repeated n times in steps S3 to S6, and a resistance inconsistency is detected when the voltage of the identification signal is not within the specified value in any case. However, more strictly speaking, the number of checks is the sum of the number of times the action is repeated through step T1 or step T2.

[0061] It should be noted that, Figure 5 The inconsistency in resistance refers to the fact that the resistance value of the identification resistor R1 in the voltage divider circuit section D is inconsistent with the resistance value of the identification resistor R1 corresponding to the target piezoelectric element. Therefore, in the case of inconsistency in resistance, the piezoelectric element in the stator 3 is not the target piezoelectric element.

[0062] In step S6, if the voltage of the identification signal is determined to be within a specified value, the process proceeds to step S7. In step S7, driving conditions are set in the control circuit unit 15 based on the identification signal. Specifically, driving conditions refer to the driving frequency range, i.e., the range of the driving frequency scan. It should be noted that multiple driving conditions are stored in the storage unit 15B of the control circuit unit 15. In this embodiment, the multiple driving conditions are a combination pattern of the four piezoelectric elements related to the range of the driving frequency scan.

[0063] In step S7, the control unit 15C determines the driving condition corresponding to the voltage of the identification signal by referring to multiple driving conditions pre-stored in the storage unit 15B. This allows for setting appropriate driving conditions in the target piezoelectric element. It should be noted that multiple combinations of modes related to the range of the driving frequency scan can also be stored in the storage unit 15B. In this case, even if the predetermined value of the identification signal voltage differs, the same control circuit unit 15 can handle the situation. Furthermore, the optimal combination of modes can be selected based on the predetermined value.

[0064] In step S8, a drive frequency scan of the ultrasonic motor element 1 is performed based on the drive conditions set in the control circuit section 15. Specifically, a drive frequency scan is performed on each piezoelectric element in the ultrasonic motor element 1. Based on this drive frequency scan, the optimal frequency for each piezoelectric element is set in the control section 15C of the control circuit section 15.

[0065] Thus, based on the selection of the driving frequency scanning range in step S7, the above scanning is performed in step S8 to set the optimal frequency. Since the above scanning is performed within an appropriate range in each piezoelectric element, it is difficult to produce deviations in the scanning time of each piezoelectric element, and the scanning time can be shortened.

[0066] In step S9, the optimal frequency set in step S8 is applied to each piezoelectric element of the ultrasonic motor element 1. After executing step S9, the process returns to step S2. The drive control device 2 repeats the above-described operation. It should be noted that, depending on the application of the ultrasonic motor element 1, additional conditions can be set for returning from step S9 to step S2. Examples of such conditions include situations where the ultrasonic motor element 1 has rotated for a fixed time, or where an abnormality is detected. Alternatively, examples of such conditions include situations where a stop signal is applied after step S9 and a fixed time has elapsed after the stop.

[0067] In this embodiment, an identification resistor R1 corresponding to the resonant frequency of each piezoelectric element in the stator 3 is used. Therefore, the resistance value of the identification resistor R1 can be set to a value corresponding to the resonant frequency shifted by mounting each piezoelectric element on the vibrating body 4. This allows for more reliable and efficient drive frequency scanning, and makes it easy to set the optimal frequency for each piezoelectric element. Consequently, the rotational efficiency of the ultrasonic motor element 1 can be easily improved.

[0068] It should be noted that the resonant frequency of each piezoelectric element can also be measured after the stator 3 is mounted on the ultrasonic motor element 1. The resistance value of the identification resistor R1 can also be a resistance value corresponding to the measurement result. In this case, the resistance value of the identification resistor R1 can be set to the resistance value after the offset is generated by mounting each piezoelectric element on the ultrasonic motor element 1. Therefore, more reliable and efficient drive frequency scanning can be performed.

[0069] The following shows an example that differs from the first embodiment, where the resistor R2 in the voltage divider circuit is a bleed resistor.

[0070] Figure 6 This is a schematic control circuit diagram of an ultrasonic motor system, a variation of the first embodiment.

[0071] The difference between this modification and the first embodiment lies in the connection of the voltage divider circuit section to the ground potential side using resistor R2, and the structure of connector 19. More specifically, one end of the voltage divider circuit section using resistor R2 branches off as in the first embodiment, connecting to the identification resistor R1 and the control circuit section 15. In this modification, the other end of the voltage divider circuit section using resistor R2 is connected to the ground potential. One end of the identification resistor R1 is connected to the voltage divider circuit section using resistor R2, and the other end is connected to the power supply section 13. Thus, the voltage divider circuit section is constructed.

[0072] It should be noted that, in addition to the identification signal wiring 9a and the drive signal wiring 9b, the connector 19 in this modified example also has a power supply wiring 19a. The identification resistor R1 is connected to the power supply unit 13 via the power supply wiring 19a.

[0073] In this modified example, the resistor R2 in the voltage divider circuit is also a bleeder resistor. The drive control device 12 operates through the same mechanism as in the first embodiment. Figure 5 The flowchart shown demonstrates how the piezoelectric element vibrates, causing the stator 3 to vibrate. In this case, the rotational efficiency of the ultrasonic motor element 11 can also be easily improved.

[0074] The generation of traveling waves will now be explained. It should be noted that, for example, WO2010 / 061508A1 discloses a structure in which multiple piezoelectric elements are distributed in the circumferential direction in the stator 3 and a traveling wave is generated by driving them. Detailed descriptions are omitted here by referencing the structure described in WO2010 / 061508A1.

[0075] Figure 7 Images (a) through (c) are schematic bottom views used to easily illustrate the traveling wave stator. It should be noted that... Figure 7 In (a) to (c), in grayscale, it is shown 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.

[0076] exist Figure 7 (a) shows the standing wave X of three waves, in Figure 7(b) shows a standing wave Y of three waves. First piezoelectric elements 5A, 5B, 5C, and 5D are arranged at a 90° interval between their central angles. In this case, since the standing waves X and Y of the three waves are excited, the central angle relative to the wavelength of the traveling wave becomes 120°. The central angle is determined by multiplying the angle of one wave (120°) by 3 / 4 to obtain an angle of 90°. The first piezoelectric element 13A is positioned at a predetermined location where the amplitude of the standing wave X of the three waves is larger, and the first piezoelectric elements 5A, 5B, 5C, and 5D are arranged at 90° intervals between their central angles. In this case, the standing waves X and Y of the three waves, whose vibrations are 90° out of phase, are excited, and the two are combined to produce... Figure 7 The traveling wave shown in (c).

[0077] It should be noted that, Figure 7 In (a) to (c), A+, A-, B+, and B- represent the polarization directions of the piezoelectric element 6. + indicates polarization in the thickness direction from the third principal surface 6a toward the fourth principal surface 6b. - indicates polarization in the opposite direction. A represents the first piezoelectric element 5A and the second piezoelectric element 5B, and B represents the third piezoelectric element 5C and the fourth piezoelectric element 5D.

[0078] As described above, by causing the vibrator 4 to generate a traveling wave that travels in the circumferential direction, the rotor 8, which is in contact with the second main surface 4b of the vibrator 4, rotates around the axis Z. It should be noted that, in this invention, the structure for generating the traveling wave is not limited to the structure of this embodiment, and various conventionally known structures for generating traveling waves can be used.

[0079] Alternatively, friction material can be fixed on the surface of the stator 3 side in the rotor body 8a. This increases the frictional force applied between the vibrating body 4 of the stator 3 and the rotor 8.

[0080] 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.

[0081] Figure 8 This is a schematic control circuit diagram of the ultrasonic motor system according to the second embodiment.

[0082] The difference between this embodiment and the first embodiment is that the resistor R2 in the voltage divider circuit is a pull-up resistor, and a switch is provided in the connector 29. The switch is used to switch the pull-up resistor on or off. Furthermore, the difference between this embodiment and the first embodiment is that the power supply unit 13, the resistor R2 in the voltage divider circuit, the analog-to-digital converter 14, and the control circuit unit 15 are all contained within a microcomputer 27. Apart from the above aspects, the ultrasonic motor system 20 of this embodiment has the same structure as the ultrasonic motor system 10 of the first embodiment.

[0083] In this embodiment, the voltage divider circuit section D21 is formed together with the resistor R2 for identifying the ultrasonic motor element 1. The drive control device 22... Figure 9 The flowchart shown illustrates how the piezoelectric element vibrates, causing the stator 3 to vibrate. It should be noted that the flowchart in the drive control device 22 is the same as in the first embodiment, except for the connection and disconnection of the pull-up resistor.

[0084] Figure 9 This is a flowchart illustrating the operation process of the drive control device in the second embodiment.

[0085] like Figure 9 As shown, the operation begins in step S21. In step S22, the counter m is set to 0. In step S23, the pull-up resistor is turned on. In this specification, turning the pull-up resistor on means electrically connecting the identification resistor R1 to the voltage divider circuit resistor R2. On the other hand, turning the pull-up resistor off means electrically isolating the identification resistor R1 from the voltage divider circuit resistor R2. In step S24, the voltage of the identification signal is measured. In step S25, the counter m is incremented by 1. In step S26, it is determined whether the voltage of the identification signal has been output. If it is determined that the voltage of the identification signal has not been output, the process proceeds to step T1.

[0086] In step T1, it is determined whether the counter m is less than the set value n. If m < n, the process returns to step S24. On the other hand, if m ≥ n in step T1, a connection error is detected.

[0087] In step S26, if it is determined that a voltage of the identification signal has been output, proceed to step S27. In step S27, determine whether the voltage of the identification signal is within a specified value. In step S27, if it is determined that the voltage of the identification signal is not within a specified value, proceed to step T2.

[0088] In step T2, it is determined whether the counter m is less than the set value n. If m < n, the process returns to step S24. On the other hand, in step T2, if m ≥ n, a resistance inconsistency is detected.

[0089] In step S27, if the voltage of the identification signal is determined to be within a specified value, the process proceeds to step S28. In step S28, the pull-up resistor is set to open. In step S29, the drive conditions are set in the control circuit section 15 based on the identification signal. In step S2A, the drive frequency of the ultrasonic motor element 1 is scanned based on the drive conditions set in the control circuit section 15. Based on this drive frequency scan, the optimal frequency for each piezoelectric element is set in the control section 15C of the control circuit section 15. In step S2B, the optimal frequency set in step S2A is applied to each piezoelectric element of the ultrasonic motor element 1. After executing step S2B, the process returns to step S22. The drive control device 22 repeatedly performs the above-described operations.

[0090] In this embodiment, similar to the first embodiment, a frequency scan suitable for each piezoelectric element can be performed. Therefore, the frequency scan time can be shortened, and deviations are less likely to occur during this time. Consequently, an optimal frequency can be easily set for each piezoelectric element, and the rotational efficiency of the ultrasonic motor element 1 can be easily improved.

[0091] Figure 10 This is a schematic control circuit diagram of the ultrasonic motor system according to the third embodiment.

[0092] The difference between this embodiment and the first embodiment is that it includes multiple sets of identification resistors, multiple sets of voltage converter resistors, a power supply unit, and an analog-to-digital converter. Apart from the above, the ultrasonic motor system 30 of this embodiment has the same structure as the ultrasonic motor system 10 of the first embodiment.

[0093] The ultrasonic motor element 31 is equipped with a first identification resistor R31 and a second identification resistor R33. The resistance value of the first identification resistor R31 is, for example, the resistance value corresponding to a piezoelectric element to which a signal of the same phase is applied. The second identification resistor R33 is the same. More specifically, in this embodiment, the resistance value of the first identification resistor R31 is the resistance value corresponding to the first piezoelectric element 5A and the second piezoelectric element 5B. The resistance value of the second identification resistor R33 is the resistance value corresponding to the third piezoelectric element 5C and the fourth piezoelectric element 5D. However, it is not limited to the above; the resistance values ​​of the first identification resistor R31 and the second identification resistor R33 may also be the resistance values ​​corresponding to piezoelectric elements to which a signal of the opposite phase is applied.

[0094] It should be noted that the system structure shown in this illustration includes two identification resistors, but more than three identification resistors can also be provided.

[0095] In this embodiment, the first identification resistor R31 and the second identification resistor R33 are provided for identifying the ultrasonic motor element 31. More specifically, the first identification resistor R31 is provided for identifying one set of piezoelectric elements in the ultrasonic motor element 31, and the second identification resistor R33 is provided for identifying the other set of piezoelectric elements. Thus, the identification resistors can also be provided for identifying one set of piezoelectric elements in a stator comprising multiple sets of piezoelectric elements. Furthermore, multiple identification resistors can be provided for identifying an ultrasonic motor element having multiple sets of piezoelectric elements.

[0096] The drive control device 32 includes a first power supply unit 33A and a second power supply unit 33B, a resistor R32 for a first voltage divider circuit and a resistor R34 for a second voltage divider circuit, and a first analog-to-digital converter 34A and a second analog-to-digital converter 34B. The connector 39 includes a first identification signal wiring 39A and a second identification signal wiring 39B.

[0097] The first voltage divider circuit section is constructed using resistor R32 and first identification resistor R31. This first voltage divider circuit section is constructed similarly to the voltage divider circuit section D in the first embodiment. More specifically, the first voltage divider circuit section using resistor R32 and the first identification resistor R31 are connected via a first identification signal wiring 39A. Furthermore, the first voltage divider circuit section using resistor R32 is connected to the first power supply section 33A. The first voltage divider circuit section is also connected to the first analog-to-digital converter section 34A. The first voltage divider circuit section outputs a first identification signal.

[0098] The second voltage divider circuit section is constructed using resistor R34 and second identification resistor R33. This second voltage divider circuit section is constructed similarly to the voltage divider circuit section D in the first embodiment. More specifically, the second voltage divider circuit section using resistor R34 and second identification resistor R33 are connected via second identification signal wiring 39B. Furthermore, the second voltage divider circuit section using resistor R34 is connected to the second power supply section 33B. The second voltage divider circuit section is also connected to the second analog-to-digital converter section 34B. The second voltage divider circuit section outputs a second identification signal.

[0099] The first analog-to-digital converter 34A and the second analog-to-digital converter 34B are connected to the control circuit section 15. The drive control device 32 is connected via... Figure 11 The flowchart shown illustrates how the piezoelectric element vibrates, causing the stator 3 to vibrate. It should be noted that the flowchart in the drive control device 32 is the same as in the first embodiment, except for the operation of measuring the voltages of the first and second identification signals respectively.

[0100] Figure 11 This is a flowchart illustrating the operation process of the drive control device in the third embodiment.

[0101] like Figure 11 As shown, the operation begins in step S31. In step S32, the counter m is set to 0. In step S33, the voltage of the first identification signal output from the first voltage divider circuit is measured. In step S34, the voltage of the second identification signal output from the second voltage divider circuit is measured. In step S35, the counter m is incremented by 1. In step S36, it is determined whether an identification signal voltage has been output. More specifically, it is determined whether the voltages of both the first and second identification signals have been output. If it is determined that neither the voltage of the first nor the second identification signal has been output, the process proceeds to step T1.

[0102] In step T1, it is determined whether the counter m is less than the set value n. If m < n, the process returns to step S33. On the other hand, if m ≥ n in step T1, a connection error is detected.

[0103] In step S36, if it is determined that the voltages of both the first identification signal and the second identification signal have been output, the process proceeds to step S37. In step S37, it is determined whether the voltage of the identification signal is within a specified value. More specifically, it is determined whether the voltages of both the first identification signal and the second identification signal are within a specified value.

[0104] The predetermined values ​​for the voltage of the first identification signal and the voltage of the second identification signal are each set separately. In this embodiment, each predetermined value is set for identifying one set of piezoelectric elements among multiple sets of piezoelectric elements included in a stator 3. Thus, the ultrasonic motor element 31 having the aforementioned multiple sets of piezoelectric elements is identified. The predetermined value for the voltage of the first identification signal is set based on a resistive voltage division determined by the resistance values ​​of the first identification resistor R31 and the first voltage divider circuit resistor R32. The predetermined value for the voltage of the second identification signal is set based on a resistive voltage division determined by the resistance values ​​of the second identification resistor R33 and the second voltage divider circuit resistor R34. In step S37, if it is determined that the voltage of the first identification signal is not within the predetermined value or if it is determined that the voltage of the second identification signal is not within the predetermined value, the process proceeds to step T2.

[0105] In step T2, it is determined whether the counter m is less than the set value n. If m < n, the process returns to step S33. On the other hand, in step T2, if m ≥ n, a resistance inconsistency is detected.

[0106] In step S37, if it is determined that the voltage of the first identification signal is within a predetermined value and the voltage of the second identification signal is within a predetermined value, the process proceeds to step S38. In step S38, driving conditions are set in the control circuit unit 15 based on the identification signals. In this embodiment, the storage unit 15B of the control circuit unit 15 stores multiple combination patterns related to the range of driving frequency scanning in the two piezoelectric elements. In step S38, based on the multiple driving conditions pre-stored in the storage unit 15B, a driving condition corresponding to the voltage of the first identification signal is selected in the control unit 15C. This allows appropriate driving conditions to be set in the first piezoelectric element 5A and the second piezoelectric element 5B. Similarly, based on the multiple driving conditions pre-stored in the storage unit 15B, a driving condition corresponding to the voltage of the second identification signal is selected in the control unit 15C. This allows appropriate driving conditions to be set in the third piezoelectric element 5C and the fourth piezoelectric element 5D.

[0107] In step S39, a drive frequency scan of the ultrasonic motor element 31 is performed based on the drive conditions set in the control circuit unit 15. Based on this drive frequency scan, the optimal frequency for each piezoelectric element is set in the control unit 15C of the control circuit unit 15. In step S3A, the optimal frequency set in step S39 is applied to each piezoelectric element of the ultrasonic motor element 31. After executing step S3A, the process returns to step S32. The drive control device 32 repeatedly performs the above-described operation.

[0108] In this embodiment, similar to the first embodiment, a frequency scan suitable for each piezoelectric element can be performed. Therefore, the frequency scan time can be shortened, and deviations are less likely to occur during this time. Consequently, an optimal frequency can be easily set for each piezoelectric element, and the rotational efficiency of the ultrasonic motor element 31 can be easily improved.

[0109] In the third embodiment, a first analog-to-digital converter 34A is connected between the first voltage divider circuit section and the control circuit section 15. A second analog-to-digital converter 34B is connected between the second voltage divider circuit section and the control circuit section 15. However, if multiple voltage divider circuit sections are provided, only one analog-to-digital converter may be provided. An example is shown below.

[0110] Figure 12 This is a schematic control circuit diagram of an ultrasonic motor system according to a variation of the third embodiment.

[0111] In this modified example, a switching switch 35 is provided between the first voltage divider circuit section, the second voltage divider circuit section, and the control circuit section 15. The switching switch 35 switches the connection between the multiple voltage divider circuit sections and the control circuit section 15. An analog-to-digital converter 14 is connected between the switching switch 35 and the control circuit section 15. In this modified example, the same method as in the third embodiment is used... Figure 11 The flowchart shown demonstrates how the piezoelectric element vibrates, causing the stator 3 to vibrate. In this case, the rotational efficiency of the ultrasonic motor element 31 can also be easily improved.

[0112] In the third embodiment, an example with two voltage divider circuit sections is shown. However, it is not limited to this; three or more voltage divider circuit sections may be provided depending on the number of piezoelectric elements or groups.

[0113] Figure 13 This is a schematic control circuit diagram of the ultrasonic motor system according to the fourth embodiment.

[0114] The ultrasonic motor system 40 includes an ultrasonic motor element 1 and an ultrasonic motor element 41. The ultrasonic motor element 1 and ultrasonic motor element 41 have the same structure as the ultrasonic motor element 1 in the first embodiment. The drive control device 32 in the ultrasonic motor system 40 drives the plurality of ultrasonic motor elements. The drive control device 32 has the same structure as the drive control device 32 in the third embodiment. In this embodiment, the drive control device 32 is connected to a plurality of connectors 9. The drive control device 32 is connected to the plurality of ultrasonic motor elements via the plurality of connectors 9.

[0115] The resistance value of the identification resistor R1 for ultrasonic motor element 1 is different from the resistance value of the identification resistor R43 for ultrasonic motor element 41. The identification resistor R1 is provided for identifying ultrasonic motor element 1. More specifically, the identification resistor R1 for ultrasonic motor element 1 is provided for identifying the group of piezoelectric elements in ultrasonic motor element 1. Similarly, the identification resistor R43 is provided for identifying ultrasonic motor element 41. More specifically, the identification resistor R43 for ultrasonic motor element 41 is provided for identifying the group of piezoelectric elements in ultrasonic motor element 41.

[0116] The identification resistor R1 for ultrasonic motor element 1, together with the resistor R32 in the first voltage divider circuit of the drive control device 32, constitutes the first voltage divider circuit. Conversely, the identification resistor R43 for ultrasonic motor element 41, together with the resistor R34 in the second voltage divider circuit of the drive control device 32, constitutes the second voltage divider circuit. The first voltage divider circuit outputs a first identification signal, and the second voltage divider circuit outputs a second identification signal. In the ultrasonic motor system 40, the piezoelectric element in each ultrasonic motor element can be identified. Therefore, each ultrasonic motor element can be identified.

[0117] In this embodiment, the same method as in the third embodiment is also used. Figure 11 The flowchart shown illustrates how piezoelectric elements vibrate, causing the stators of each ultrasonic motor element to vibrate. In this case, an optimal frequency can be easily set for each piezoelectric element of each ultrasonic element. Therefore, the rotational efficiency of multiple ultrasonic motor elements can be easily improved.

[0118] In the fourth embodiment, an example is shown where the ultrasonic motor system 40 includes two ultrasonic motor elements. However, it is not limited to this; the ultrasonic motor system 40 may also include three or more ultrasonic motor elements. Depending on the number of ultrasonic motor elements, the number of piezoelectric elements, or the number of groups of piezoelectric elements, three or more voltage divider circuit sections may also be provided.

[0119] Explanation of reference numerals in the attached figures

[0120] 1…Ultrasonic motor components;

[0121] 2…drive control device;

[0122] 3…Stator;

[0123] 4…vibrating body;

[0124] 4a, 4b... First main face, second main face;

[0125] 5A~5D…First piezoelectric element~Fourth piezoelectric element;

[0126] 6…piezoelectric elements;

[0127] 6a, 6b... Third principal face, fourth principal face;

[0128] 7A, 7B… First electrode, second electrode;

[0129] 8…rotor;

[0130] 8a…rotor body;

[0131] 8b…rotation axis;

[0132] 9… connectors;

[0133] 9a… Wiring for identifying signals;

[0134] 9b… Wiring for drive signals;

[0135] 10… Ultrasonic motor system;

[0136] 11…Ultrasonic motor components;

[0137] 12… Drive control device;

[0138] 13…Power Supply Section;

[0139] 14…Analog-to-digital converter;

[0140] 15…Control Circuit Section;

[0141] 15A… Measurement Section;

[0142] 15B…Storage Section;

[0143] 15C…Control Unit;

[0144] 16…Drive circuit section;

[0145] 19… connectors;

[0146] 19a…Power supply wiring;

[0147] 20… Ultrasonic motor system;

[0148] 22…drive control device;

[0149] 27…microcomputers;

[0150] 29… connectors;

[0151] 30… Ultrasonic motor system;

[0152] 31…Ultrasonic motor components;

[0153] 32… Drive control device;

[0154] 33A, 33B... First power supply section, second power supply section;

[0155] 34A, 34B... First analog-to-digital converter, second analog-to-digital converter;

[0156] 35… toggle switch;

[0157] 39… connector;

[0158] 39A, 39B... Wiring for the first identification signal, wiring for the second identification signal;

[0159] 40… Ultrasonic motor system;

[0160] 41…Ultrasonic motor components;

[0161] D, D21… Voltage divider circuit section;

[0162] R1…Identification resistor;

[0163] R2…Resistor used in voltage divider circuit section;

[0164] R31… First identification resistor;

[0165] R32…Resistor used in the first voltage divider circuit;

[0166] R33…Second identification resistor;

[0167] R34…Resistor used in the second voltage divider circuit;

[0168] R43…Identification resistor.

Claims

1. A drive control device for driving an ultrasonic motor element having a piezoelectric element, wherein, The drive control device includes: The voltage divider circuit section uses a resistor, which together with the identification resistor used to identify the ultrasonic motor element constitutes the voltage divider circuit section. The control circuit section is connected to the voltage divider circuit section and sets the driving conditions of the ultrasonic motor element according to the voltage of the identification signal used to identify the ultrasonic motor element. as well as The drive circuit section applies a drive voltage to the piezoelectric element based on the drive conditions set by the control circuit section. The control circuit set the scanning range of the driving frequency of the piezoelectric element, the driving circuit scans the driving frequency of the piezoelectric element within the scanning range of the driving frequency set by the control circuit, and the control circuit sets the driving conditions based on the result of the driving frequency scanning.

2. The drive control device according to claim 1, wherein, The control circuit section includes: A storage unit that stores multiple modes of the scan range of the driving frequency; and The control unit selects the scanning range of the drive frequency from the plurality of modes and sets the drive conditions.

3. The drive control device according to claim 1 or 2, wherein, One end of the resistor in the voltage divider circuit is connected to the identification resistor and the control circuit, while the other end is connected to the power supply.

4. The drive control device according to claim 1 or 2, wherein, One end of the resistor in the voltage divider circuit is connected to the identification resistor and the control circuit, while the other end is connected to the ground potential.

5. The drive control device according to claim 3, wherein, The resistor used in the voltage divider circuit is a pull-up resistor. The drive control device also includes a switch that toggles the connection between the voltage divider circuit resistor and the identification resistor.

6. The drive control device according to claim 1 or 2, wherein, The drive control device includes a plurality of resistors for the voltage divider circuit section, which together with the plurality of identification resistors constitute the voltage divider circuit section.

7. The drive control device according to claim 6, wherein, The drive control device also includes a switching switch, which is configured between the plurality of voltage divider circuit sections and the control circuit section to switch the connection between the plurality of voltage divider circuit sections and the control circuit section.

8. The drive control device according to claim 7, wherein, The drive control device also includes an analog-to-digital converter connected between the switching switch and the control circuit to perform digital conversion on the identification signal.

9. The drive control device according to claim 1 or 2, wherein, The drive control device also includes an analog-to-digital converter connected between the voltage divider circuit and the control circuit to perform digital conversion on the identification signal.

10. An ultrasonic motor system, comprising: The drive control device according to any one of claims 1 to 5; and The ultrasonic motor element has the piezoelectric element and the identification resistor.

11. An ultrasonic motor system, comprising: The drive control device according to any one of claims 6 to 9; and The ultrasonic motor element has a plurality of the piezoelectric elements and a plurality of the identification resistors.

12. An ultrasonic motor system, comprising: The drive control device according to any one of claims 6 to 9; and The plurality of ultrasonic motor elements each have the piezoelectric element and the identification resistor.

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