JP5627655B2 - Multi-degree-of-freedom drive - Google Patents

Description

  The present invention relates to a multi-degree-of-freedom driving device that moves a moving body in multiple directions using a plurality of vibrators.

  Conventionally, as a multi-degree-of-freedom driving device, a surface wave actuator that realizes driving in three directions of X, Y, and θ using a linear actuator has been proposed (see Patent Document 1).

  This surface wave actuator will be described with reference to FIG. FIG. 20 is a perspective view showing a conventional surface acoustic wave actuator partially cut away.

  As shown in FIG. 20, the surface wave actuator includes three sets of surface wave generation mechanisms 6a, 6b, and 6c that are attached to the upper base plate 2 and the lower base plate 3 and arranged to face each other. A driving voltage is applied to each of the surface wave generating mechanisms 6a, 6b, 6c, thereby generating a surface wave. The surface waves generated by the surface wave generating mechanisms 6a, 6b, and 6c act on the moving body plate 1 as a driving force for moving the moving body plate 1, respectively.

  Here, when the force components applied to the moving plate 1 by the surface waves generated by the surface wave generating mechanisms 6a, 6b, and 6c are represented by vectors M1a, M1b, and M1c, respectively, a vector obtained by combining the vectors M1a, M1b, and M1c is obtained. The moving body plate 1 is moved in the direction shown.

Japanese Patent Publication No. 07-034660

  However, in the surface wave actuator, if there is a difference in output characteristics between the surface wave generating mechanisms 6a, 6b, and 6c, the surface wave generating mechanisms 6a, 6b, and 6c are controlled to generate a predetermined driving force. May not be possible.

  Therefore, a method of selecting a predetermined number of surface wave generation mechanisms having substantially the same output characteristics from among a plurality of surface wave generation mechanisms whose output characteristics are known in advance, and incorporating the selected predetermined number of surface wave generation mechanisms Can be considered. However, even if a predetermined number of surface wave generation mechanisms having substantially the same output characteristics are incorporated in the apparatus, their attachment states, for example, contact forces between the surface wave generation mechanisms and the moving body plate 1 may be different. In such a case, the output characteristics of the surface wave generating mechanisms are not uniform, and the driving of each surface wave generating mechanism may not be stably controlled.

  An object of the present invention is to provide a multi-degree-of-freedom driving device capable of aligning the output characteristics of each vibrator in a state of being incorporated in the device.

In order to achieve the above object, a multi-degree-of-freedom drive device according to the present invention includes a plurality of vibrators driven by drive voltages generated based on values set in a plurality of parameters, and the plurality of vibrators. A movable body that is brought into contact with each of the vibrators so as to be movable in multiple directions, and the plurality of parameters are set to values that are variable according to driving of the corresponding vibrators. parameter and the phase difference is, and a second parameter different from the parameters of the first, of the plurality of voltages applied to the respective vibrators to generate a substantially equal rate to the plurality of transducers, the based on the value of the first parameter, and determining means for determining whether or not each of the output characteristics of the vibrator is matched, the respective output characteristics of the vibrator by the determination means does not coincide determine And changing means for changing a value set in the second parameter for at least one vibrator so that output characteristics of the driven vibrators coincide with each other. And

  According to the present invention, the output characteristics of the respective vibrators can be made uniform in the state of being incorporated in the apparatus.

1 is a plan view showing a multi-degree-of-freedom drive device according to a first embodiment of the present invention. It is a side view of the multi-degree-of-freedom drive device of FIG. (A) is a longitudinal sectional view showing the configuration of the vibrator 11, and (b) is a plan view showing electrode regions formed in the piezoelectric element of the vibrator 11 of FIG. 3 (a). It is a figure which shows the vibration mode (A mode and B mode) which generate | occur | produces in the vibrator | oscillator 11 of FIG. It is a block diagram which shows the structure of the control system for controlling the drive of the vibrators 11-13 in the multi-degree-of-freedom drive device of FIG. FIG. 6 is a block diagram illustrating a configuration of the switching circuit of FIG. 5. It is a figure which shows the driving force of each vibrator | oscillator 11-13 when moving the moving body 10 straightly to a X direction. It is a figure which shows the driving force of each vibrator | oscillator 11-13 when moving the moving body 10 straightly to a Y direction. It is a figure which shows the driving force of each vibrator | oscillator 11-13 when rotating the mobile body 10 to (theta) direction. The figure which shows the case where the drive force (vector Ms) which synthesize | combined the drive force of each vibrator | oscillator 12 and 13 at the time of moving the moving body 10 to X direction linearly, and the drive force (vector M1) of the vibrator | oscillator 11 do not correspond. It is. FIG. 11 is a diagram illustrating a relationship between a frequency of a driving voltage applied to each vibrator 12 and 13 and a moving speed of a moving body 10 in a driving force generation state illustrated in FIG. 10. FIG. 6 is a diagram showing the relationship between the frequency of the drive voltage and the moving speed of the moving body when the output characteristics of the vibrators are matched by changing the voltage value of the drive voltage applied to the vibrator. In the second embodiment of the present invention, each vibrator 11 controlled when the vibrators 11 to 13 are driven by the drive voltages VA and VB having the frequency f3 and the voltage value V3 to rotate the moving body 10 in the θ direction. It is a figure which shows the phase difference between the drive voltages VA and VB of -13. It is a figure which shows the relationship between the phase difference between the drive voltages VA and VB applied to each vibrator | oscillator 11-13, and speed. It is a figure which shows the relationship between the frequency and the speed between drive voltage VA and VB which are each applied to each vibrator | oscillator 11-13. The phase difference between the drive voltages VA and VB having the frequency f3 and the voltage value V3 applied to the vibrators 11 and 12 and the phase difference between the drive voltages VA and VB having the frequency f4 and the voltage value V3 applied to the vibrator 13 are shown. FIG. The drive state of each vibrator | oscillator 11-13 at the time of determining whether the output characteristics of each vibrator | oscillator 12 and 13 correspond in the multi-degree-of-freedom drive device which concerns on the 3rd Embodiment of this invention is shown. FIG. FIG. 6 is a diagram illustrating control amounts of phase differences between drive voltages VA and VB applied to vibrators 12 and 13, respectively. The drive state of each vibrator | oscillator 11-13 at the time of determining whether the output characteristics of each vibrator | oscillator 12 and 13 correspond in the multi-degree-of-freedom drive device which concerns on the 4th Embodiment of this invention is shown. FIG. It is a perspective view which partially fractures and shows the conventional surface wave actuator.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a plan view showing a multi-degree-of-freedom drive device according to the first embodiment of the present invention. FIG. 2 is a side view of the multi-degree-of-freedom driving device of FIG.

  As shown in FIGS. 1 and 2, the multi-degree-of-freedom drive device includes a base plate 9. Three vibrators 11, 12, and 13 are attached to the base plate 9 to move the moving body 10 in three directions of X, Y, and θ on a predetermined plane in cooperation with each other. ing. Here, the X direction and the Y direction are directions orthogonal to each other on the plane, and the θ direction is a rotation direction around an axis orthogonal to the plane. The vibrators 11, 12, and 13 are arranged at an angular interval of 2π / 3 (rad) along a circumferential direction around a predetermined O point on the base plate 9.

  The base plate 9 includes a position sensor 21 for detecting the amount of movement of the moving body 10 in the X direction and two position sensors 22 and 23 for detecting the amount of movement of the moving body 10 in the Y direction. Is attached. The position sensor 21 is arranged at a position separated from the point O by a distance d. Each of the position sensors 22 and 23 is disposed at a distance d from the point O so as to face each other.

  As shown in FIG. 2, three scale parts 31, 32, and 33 are attached to the moving body 10. Each scale part 31, 32, 33 is arranged so as to face the corresponding position sensor 21, 22, 23. The position sensor 21 detects the amount of movement of the scale unit 31 in the X direction (the amount of movement of the moving body 10 in the X direction), and outputs a signal indicating the detected amount of movement. Each position sensor 22, 23 detects the amount of movement of the corresponding scale unit 32, 33 in the Y direction (the amount of movement of the moving body 10 in the Y direction), and outputs a signal indicating the detected amount of movement. .

  The vibrators 11, 12, and 13 will be described in detail with reference to FIGS. FIG. 3A is a longitudinal sectional view showing the configuration of the vibrator 11, and FIG. 3B is a plan view showing electrode regions formed in the piezoelectric element of the vibrator 11 of FIG. . FIG. 4 is a diagram showing vibration modes (A mode and B mode) generated in the vibrator 11 of FIG. Here, since the vibrators 11, 12, and 13 have the same configuration, the configuration of the vibrator 11 will be described.

  As shown in FIG. 3A, the vibrator 11 includes a vibrating body 18 made of a flat plate-like elastic member such as stainless steel. A projecting portion 19 is provided on one surface of the vibrating body 18, and the projecting portion 19 and the moving body 10 are in pressure contact with a pressurizing member (not shown) such as a spring member. A piezoelectric element (electromechanical energy conversion element) 17 is bonded to the other surface of the vibrating body 18.

  As shown in FIG. 3B, the piezoelectric element 17 is formed with two electrode regions 17a and 17b arranged along the longitudinal direction (X direction). The polarization directions in the electrode regions 17a and 17b are the same direction (+). Of each of the electrode regions 17a and 17b, the drive voltage VA is applied to the electrode region 17a, and the drive voltage VB is applied to the electrode region 17b.

  Here, the drive voltages VA and VB are alternating voltages having a frequency near the resonance frequency of the A mode and having a π (rad) phase difference. When the drive voltages VA and VB are applied to the corresponding electrode regions 17a and 17b, at a certain moment, the electrode region 17a of the piezoelectric element 17 contracts and the electrode region 17b expands. In other moments, the relationship is reversed. As a result, vibration in the A mode shown in FIG. 4A is generated in the vibrator 11 (vibrating body 18).

  When the drive voltages VA and VB have frequencies close to the B-mode resonance frequency and have the same phase, the entire piezoelectric element 17 (two electrode regions 17a and 17b) extends at a certain moment. It will shrink at other moments. As a result, B-mode vibration shown in FIG. 4B is generated in the vibrator 11 (vibrating body 18).

  The A-mode vibration and the B-mode vibration are combined, and a driving force for driving the moving body 10 is generated by the combined vibration. In the case of the vibrator 11, the vibrator 11 generates a driving force that moves the moving body 10 in the X direction. Further, by changing the phase difference between the drive voltages VA and VB input to the electrode regions 17a and 17b, the generation ratio of the A-mode vibration and the B-mode vibration can be changed. By controlling the vibration generation ratio of each mode, it is possible to control the driving force (the moving speed of the moving body 10 in the X direction) at which the vibrator 11 drives the moving body 10. Similarly, the vibrators 12 and 13 generate a driving force for driving the moving body 10.

  Next, a drive control system for performing drive control of the vibrators 11 to 13 will be described with reference to FIGS. FIG. 5 is a block diagram showing a configuration of a control system for controlling the driving of the vibrators 11 to 13 in the multi-degree-of-freedom driving device of FIG. FIG. 6 is a block diagram showing the configuration of the switching circuit of FIG.

  As shown in FIG. 5, the control system for controlling the driving of the vibrators 11 to 13 includes a control unit 50 including a CPU, a ROM, a RAM (not shown), and the like. The control unit 50 controls the moving body 10 (a reference position provided in the moving body 10) to move from the current position to the target position. Here, the target position indicates the position of the moving body 10 or the position of the object moved in conjunction with the movement of the moving body 10 (position on the XY coordinates), for example, an operation unit (not shown). It is input from. And the control part 50 produces | generates the control signals S11-S13 for moving the mobile body 10 to the said target position. The control signals S11 to S13 are control signals for controlling the driving of the corresponding transducers 11 to 13, respectively, and are output to the corresponding drive pulse generators 53 to 55 of the drive unit 51. Each control signal S11-S13 includes parameters α11-α13, β11-β13. The values of the parameters α11 to α13 are values that define the frequencies of the drive voltages VA and VB applied to the vibrators 11 to 13, respectively. The values of the parameters β11 to β13 are values that define the phase difference between the drive voltages VA and VB applied to the vibrators 11 to 13 (phase difference between the A and B phases).

  In addition, the control unit 50 generates three control signals S14 to S15 for controlling the voltage values of the three DC voltages Vc11 to Vc13 generated by the power supply circuit 59 of the drive unit 59, and outputs them to the power supply circuit 59. . Each control signal S14 to S15 includes corresponding parameters γ11 to γ13. The values of the parameters γ11 to γ13 are values that define the voltage values of the three DC voltages Vc11 to Vc13 generated by the power supply circuit 59.

  The control unit 50 varies the values of the parameters α11 to α13 and β11 to β13, so that the frequencies of the drive voltages VA and VB applied to the vibrators 11 to 13 and the phase difference between the drive voltages VA and VB (A , B phase difference). Further, the control unit 50 controls the voltage values of the drive voltages VA and VB applied to the vibrators 11 to 13 by changing the values of the parameters γ11 to γ13. In normal times, the drive voltages VA and VB applied to the vibrators 11 to 13 are held at the corresponding values, and the drive voltages VA to be applied to the vibrators 11 to 13 are maintained. , VB are controlled in phase difference. And the driving force of each vibrator | oscillator 11-13 is controlled by control of the phase difference between drive voltage VA and VB.

  The drive unit 51 includes a power supply circuit 59, an oscillator 52, three drive pulse generators 53 to 55, and three switching circuits 56 to 58. The power supply circuit 59 generates DC voltages Vc11 to Vc13 having voltage values defined by the parameters γ11 to γ13 included in the control signals S14 to S15 from an input power supply (not shown), respectively. . The DC voltages Vc11 to Vc13 are supplied to the switching circuits 56 to 58.

  The oscillator 52 generates a reference clock. The drive pulse generator 53 generates the A-phase pulse, the A-phase pulse, the B-phase pulse, and the / B-phase pulse based on the control signal S11, and stops the generation of each pulse. Here, the A-phase pulse and the / A-phase pulse are pulses having a phase difference of π (rad) and the same pulse width. Similarly, the B-phase pulse and the / B-phase pulse are pulses having a phase difference of π (rad) and the same pulse width. The A-phase pulse, the A-phase pulse, the B-phase pulse, and the / B-phase pulse are generated based on the value of the parameter α11 and the value of the parameter β11 with reference to the reference clock of the oscillator 52.

  Similarly to drive pulse generator 53, drive pulse generators 54 and 55 generate A-phase pulses, A-phase pulses, B-phase pulses, and / B-phase pulses based on control signals S12 and S13. Make that stop. The A-phase pulse, the / A-phase pulse, the B-phase pulse, and the / B-phase pulse generated by the drive pulse generators 54 and 55 are based on the reference clock of the oscillator 52 and the values and parameters of the parameters α12 and α13. It is generated based on the values of β12 and β13.

  The A-phase pulse, the / A-phase pulse, the B-phase pulse and the / B-phase pulse generated by the drive pulse generators 53 to 55 are input to the corresponding switching circuits 56 to 58, respectively.

  As illustrated in FIG. 6, the switching circuit 56 includes a plurality of FETs 151 to 158 that are switching elements. Corresponding A-phase pulse, / A-phase pulse, B-phase pulse, and / B-phase pulse are input to the FETs 151 to 158, respectively. For example, when the A phase pulse becomes H (High), the FETs 151 and 154 are turned on, and a current flows from the A phase to the / A phase. On the contrary, when the / A phase pulse becomes H, the FETs 153 and 152 are turned on, and a current flows from the / A phase to the A phase. As described above, regarding the A phase, the ON operation of the FETs 151 to 154 is controlled by the A phase pulse and the / A phase pulse, and the DC voltage Vc11 is converted into the drive voltage VA having a frequency corresponding to the vibrator 11 and applied. The The voltage value of the DC voltage Vc11 is a voltage value defined by the value of the parameter γ11.

  Similarly, regarding the B phase, the ON operation of the FETs 155 to 158 is controlled by the B phase pulse and the / B phase pulse, and the DC voltage Vc11 corresponds to the frequency corresponding to the vibrator 11 and the driving voltage VA. A drive voltage VB having a phase difference is converted and applied.

  In this way, the drive voltages VA and VB having the frequency, phase difference, and voltage value respectively defined by the values of the parameters α11, β11, and γ11 are applied to the vibrator 11.

  Further, an impedance element 41 for matching the impedance with the vibrator 11 is inserted between the vibrator 11 and the FETs 151 and 152. An impedance element 42 is inserted between the vibrator 11 and the FETs 155 and 156. The impedance elements 41 and 42 are for driving the vibrator 11 with low voltage and high efficiency.

  Similarly, the switching circuit 57 has a frequency, a phase difference, and a voltage value corresponding to the values of the parameters α12, β12, and γ12 based on the A phase pulse, the / A phase pulse, the B phase pulse, and the / B phase pulse. Drive voltages VA and VB are applied to the vibrator 12. In addition, the switching circuit 58 applies a frequency and a level corresponding to the values of the parameters α13, β13, and γ13 to the vibrator 13 based on the A phase pulse, the / A phase pulse, the B phase pulse, and the / B phase pulse. Driving voltages VA and VB having a phase difference and a voltage value are applied. Since the switching circuits 57 and 58 have the same configuration as the switching circuit 56 described above, description thereof is omitted.

  As described above, the drive unit 51 generates the drive voltages VA and VB to be applied to the vibrators 11 to 13 based on the values of the parameters α11 to 13, β11 to 13, and γ11 to 13 for the vibrators 11 to 13. .

  Next, control for driving the vibrators 11 to 13 by the control unit 50 will be described with reference to FIGS. FIG. 7 is a diagram illustrating the driving force of each transducer 11 to 13 when the moving body 10 is linearly moved in the X direction. FIG. 8 is a diagram illustrating the driving force of each vibrator 11 to 13 when the moving body 10 is moved straight in the Y direction. FIG. 9 is a diagram illustrating the driving force of each transducer 11 to 13 when the moving body 10 is rotated in the θ direction. FIG. 10 shows a case where the driving force (vector Ms) obtained by combining the driving forces of the vibrators 12 and 13 when moving the moving body 10 straight in the Y direction does not match the driving force (vector M1) of the vibrator 11. FIG.

  When moving the moving body 10 from the current position to the target position, the control unit 50 determines a moving path for causing the reference portion of the moving body 10 to reach the target position from the current position. This moving path is formed by individually combining a path due to a straight movement in the X direction, a path due to a straight movement in the Y direction, and a path due to rotation in the θ direction. The movement amount (or movement speed) is set. Then, the control unit 50 generates control signals S <b> 11 to S <b> 13 for moving the moving body 10 along each path that constitutes the determined moving path, and outputs the control signals S <b> 11 to S <b> 13 to the driving unit 51. Further, the control unit 50 outputs control signals S14 to S16 for setting the voltage values of the DC voltages Vc11 to Vc13 generated by the power supply circuit 59 to corresponding voltage values to the power supply circuit 59.

  As a result, drive voltages VA and VB having frequencies, phase differences, and voltage values defined by the parameters α11 to α13, β11 to β13, and γ11 to γ13 are applied to the corresponding vibrators 11 to 13, and the corresponding vibrations are applied. The children 11 to 13 are driven. And the mobile body 10 is moved along the said path | route.

  As the moving body 10 starts moving, the control unit 50 detects the moving direction and moving amount (or moving speed) of the moving body 10 based on the output values of the position sensors 21 to 23. Detection of the moving direction and the moving amount (or moving speed) of the moving body 10 is performed using equations (1) to (3) described later. Then, the control unit 50 controls the corresponding control signals S11 to S11 based on the deviation between the detected moving direction and moving amount (moving speed) of the moving body 10 and the moving direction and moving amount (moving speed) of the corresponding route. Thirteen parameters β11 to 13 are variably controlled. That is, the phase difference between the drive voltages VA and VB applied to the corresponding vibrators 11 to 13 is controlled. Accordingly, the driving force (moving body) of the corresponding vibrators 11 to 13 is set so that the actual moving direction and moving amount (moving speed) of the moving body 10 become the moving direction and moving amount (moving speed) of the corresponding path. 10) is controlled.

  Here, the moving direction of the moving body 10 and a method for calculating the moving amount in the moving direction based on the output values from the position sensors 21 to 23 by the control unit 50 will be briefly described.

  Assuming that the output value of the position sensor 21 is D21, the output values of the position sensors 22 and 23 are D22 and D23, and the amount of movement of the moving body 10 in the Y direction is Dy, the amount of movement Dy is the following (1). It is obtained by the formula.

Dy = (D22 + D23) / 2 (1)
Further, when the rotation angle of the moving body 10 in the θ direction is θr, the rotation angle θr can be obtained by the following equation (2).

θr = arccos {(D22−D23) / (2d)} (2)
Further, assuming that the moving amount of the moving body 10 in the X direction is Dx, the moving amount Dx is obtained by the following equation (3).

Dx = D21 + d × sin θr (3)
Using these equations (1) to (3), the moving direction (X, Y, θ direction) of the moving body 10, the moving amount in the moving direction, and the moving speed can be obtained.

  When the moving body 10 is linearly moved in the X direction, the vibrators 11 to 13 are driven based on the corresponding control signals S11 to S13. Here, it is assumed that the base plate 9 is placed on a horizontal plane and gravity acts on the moving body 10 in the vertical direction. In this case, as shown to Fig.7 (a), in each vibrator | oscillator 11-13, driving force (vector M11-M13) generate | occur | produces and the moving body 10 is moved by each driving force. At this time, as shown in FIG. 7B, the driving force (vector M12) of the vibrator 12 and the driving force (vector M13) of the vibrator 13 are combined into a driving force (vector Ms). The combined driving force (vector Ms) needs to match the driving force (vector M1) of the vibrator 11.

Therefore, the phase difference between the drive voltages VA and VB applied to the vibrators 11 to 13 (parameters β11 to β1) is set so that the driving force (vector Ms) matches the driving force (vector M1) of the vibrator 11. 13) is controlled. In this control, the moving direction and the moving amount of the moving body 10 are detected based on the output values of the position sensors 21 to 23. Based on the detected moving direction and moving amount of the moving body 10, the phase difference (parameters β11 to 13) between the drive voltages VA and VB applied to the vibrators 11 to 13 is controlled. The frequencies and drive voltages of the drive voltages VA and VB applied to the vibrators 11 to 13 are held at preset values (parameters α11 to α13 and γ11 to 13), respectively.

  When the moving body 10 is linearly moved in the Y direction, the vibrators 11 to 13 are driven based on the corresponding control signals S11 to S13. Here, since the vibrator 11 is a vibrator for moving the moving body 10 in the X direction, the vibrator 11 is driven in the B mode (the mode shown in FIG. 4B). In the case of this B mode, drive voltages VA and VB having almost no phase difference are applied to the vibrator 11, and no vibration is generated to move the moving body 10 in either the X or Y direction. Only occurs. However, due to this vertical vibration, the frictional force between the contact surface between the protrusion 19 of the vibrating body 18 of the vibrator 11 and the moving body 10 becomes substantially zero, and the load that the moving body 10 receives from the vibrator 11 is unloaded. It becomes.

  Corresponding drive voltages VA and VB are applied to the vibrators 12 and 13, respectively. As shown in FIG. 8A, the vibrators 12 and 13 drive force (vector) that drives the moving body 10. M12, M13). Here, as shown in FIG. 8B, the driving force (vector M12) of the vibrator 12 and the driving force (vector M13) of the vibrator 13 are combined to drive the moving body 10 (vector Ms). ) Then, based on the detected moving direction and moving amount of the moving body 10, the driving voltages VA and VA applied to the vibrators 12 and 13, respectively, so that the driving force (vector Ms) becomes the driving force in the Y direction. The phase difference between VBs is controlled. Here, the frequencies and drive voltages of the drive voltages VA and VB applied to the vibrators 12 to 13 are held at preset values, respectively.

  When the movable body 10 is rotated in the θ direction, the vibrators 11 to 13 are driven based on the corresponding control signals S11 to S13. In this case, as shown in FIG. 9, a driving force (vectors M11 to M13) is generated in each of the vibrators 11 to 13, and the moving body 10 is rotated in the θ direction by each driving force. Based on the detected moving direction and moving amount of the moving body 10, the vibrators 11 to 13 are applied to the vibrators 11 to 13 so that the driving forces (vectors M11 to M13) of the vibrators 11 to 13 are the same. The phase difference between the drive voltages VA and VB to be applied is controlled. Here, the frequencies and drive voltages of the drive voltages VA and VB applied to the vibrators 11 to 13 are respectively held at preset values.

  In this way, the vibrators 11 to 13 are driven by the control of the phase difference (parameters β11 to 13) between the drive voltages VA and VB applied to the vibrators 11 to 13, respectively, and the moving body 10 moves in the target direction. Can be moved by the target movement amount.

  However, as shown in FIG. 10, for example, when the moving body 10 is linearly moved in the Y direction, the driving force (vector Ms) obtained by combining the driving forces of the vibrators 12 and 13 does not become the driving force in the Y direction. There is a case. For example, when the resonance frequencies of the vibrators 12 and 13 are greatly different and their output characteristics are greatly different, the magnitudes of the driving forces of the vibrators 12 and 13 are different, and the combined driving force (vector Ms) is different. The direction will not match the Y direction.

  In such a case, by controlling (variable) the phase difference between the driving voltages VA and VB applied to the vibrators 12 and 13, respectively, the magnitude of the driving force generated by the vibrators 12 and 13 is the same. Control to do this is attempted. However, individual differences of motors may be greatly deviated due to factors such as the resonance frequency being deviated. In this case, each vibrator is controlled so that a driving force (vector Ms) obtained by combining the driving forces of the vibrators 12 and 13 becomes a driving force in the Y direction only by controlling the phase difference between the driving voltages VA and VB. The magnitude of the driving force generated by 12, 13 cannot be controlled to a desired magnitude.

  Therefore, in the present embodiment, in order to avoid the situation as described above, first, the movable body 10 is moved by driving the corresponding vibrators 11 to 13 with the corresponding drive voltages VA and VB. . Then, based on the movement result of the moving body 10, it is determined whether or not the output characteristics of the transducers 11 to 13 match. Here, when it is determined that the output characteristics of the vibrators 11 to 13 do not match, the output characteristics of the corresponding vibrators 11 to 13 are corrected so that the output characteristics of the vibrators 11 to 13 match. Is done.

  In the correction of the output characteristics, the values of the parameters α11 to α13 or γ11 to γ13 of the corresponding vibrators 11 to 13 (the frequencies of the drive voltages VA and VB) are set so that the output characteristics of the vibrators 11 to 13 are substantially matched. Or the voltage value) is changed. As a result, for each of the vibrators 11 to 13 having the same output characteristics, the vibrators 11 to 13 are driven only by controlling the phase difference between the drive voltages VA and VB applied to the vibrators 11 to 13. It is possible to control the magnitude of the force to a desired magnitude.

  The correction of the output characteristics will be described with reference to FIGS. FIG. 11 is a diagram showing the relationship between the frequency of the driving voltage applied to each transducer 12 and 13 and the moving speed of the moving body 10 in the state where the driving force is generated as shown in FIG. FIG. 12 is a diagram showing the relationship between the driving voltage frequency and the moving speed of the moving body 10 when the output characteristics of the vibrators 12 and 13 are matched by changing the voltage value of the driving voltage applied to the vibrator 12. is there.

  For example, when determining whether or not the output characteristics of the vibrators 12 and 13 are the same, first, the target direction of the moving body 10 is set to the Y direction, and the moving body 10 is moved to the Y direction by the vibrators 12 and 13. Control to move straight in the direction is performed. In this control, as described above, the vibrator 11 is driven in the B mode, and the drive voltages VA and VB having the same frequency, the same amplitude, and the same phase difference are applied to the vibrators 12 and 13, respectively. The That is, the values of the parameters α12, β12, and γ12 for the vibrator 12 are the same as the values of the parameters α13, β13, and γ13 for the vibrator 13, respectively.

  When the moving body 10 is moved by the vibrators 12 and 13, the control unit 50 uses the output values of the position sensors 22 and 23, respectively, to move the moving body 10 in the Y direction in the moving directions VY1 and VY2 (predetermined). The amount of movement in the Y direction per time) is calculated. The moving speed VY1 is a speed calculated based on the output value of the position sensor 22, and the moving speed VY2 is a speed calculated based on the output value of the position sensor 23.

  When it is determined by these position sensors 21, 22, and 23 that the moving body 10 is driven only in the Y direction, as shown in FIG. 8B, the driving forces generated by the vibrator 12 and the vibrator 13, respectively. A driving force (combined vector Ms) obtained by combining (vectors M12 and M13) is a driving force for driving the moving body 10 in the Y direction. Therefore, if the moving direction calculated from each of the output values of the position sensors 21, 22, and 23 is the same as the Y direction, the control unit 50 has the same driving force for the vibrator 12 and the vibrator 13. Is determined. That is, the control unit 50 determines that the output characteristics of the vibrators 12 and 13 match.

  On the other hand, if the movement directions calculated from the output values of the position sensors 21, 22, and 23 do not coincide with the Y direction, the magnitude of the driving force of the vibrator 12 and the magnitude of the driving force of the vibrator 13 are determined. Will be different. In this case, as shown in FIG. 10, the direction of the driving force (vector Ms) obtained by combining the driving forces of the vibrator 12 and the vibrator 13 does not coincide with the Y direction that is the target moving direction of the moving body 10. Therefore, if the moving directions calculated from the output values of the position sensors 21, 22, and 23 are not the same, the control unit 50 does not have the same driving force for the vibrators 12 and 13, and the vibrators 12 and 13 do not have the same driving force. It is determined that the output characteristics of 13 do not match.

  Further, the difference in the magnitude of the driving force of each vibrator 12, 13 can be obtained based on the moving direction obtained by the calculation.

  When it is determined that the output characteristics of the vibrators 12 and 13 do not match, the output characteristics of one of the vibrators 12 and 13 are matched with the output characteristics of the other vibrator. It is corrected. Here, the output characteristics are corrected by changing the values (frequencies) of the parameters α12 to α13 of the corresponding vibrator.

  For example, as shown in FIG. 11, it is assumed that drive voltages VA and VB having the same frequency f0, the same amplitude, and the same phase difference (phase difference between A and B phases) are applied to the vibrators 12 and 13, respectively. Here, the relationship between the frequency of the drive voltage to be applied and the moving speed (output characteristics) of the moving body 10 is represented by curves Out12 and 13 for the vibrators 12 and 13, respectively.

  In this example, it is assumed that the resonance frequencies of the vibrators 12 and 13 (vibrating bodies) are different and the resonance frequency of the vibrator 12 is sufficiently lower than the frequency f0 of the applied drive voltages VA and VB. In this case, the moving speed due to the output of the vibrator 12 is smaller than the value moving speed due to the output of the position vibrator 13. That is, the driving force of the moving body 10 by the vibrator 12 is smaller than the driving force of the moving body 10 by the vibrator 13.

  Therefore, the control unit 50 drives the drive voltage VA, V applied to the vibrator 12 so that the speed difference ΔV (vector gradient) of the moving speed is zero, that is, the magnitude of the drive force of the vibrator 12 is increased. The value of parameter α12 that defines the frequency of VB is changed. For example, as shown in FIG. 11, the value of the parameter α12 is changed to a value in which the frequencies of the drive voltages VA and VB applied to the vibrator 12 are set to the frequency f1 (a frequency near the resonance frequency of the vibrator 12). As a result, the output characteristics of the vibrator 12 are corrected so as to substantially match the output characteristics of the vibrator 13.

  When the output characteristics of the vibrators 12 and 13 are matched, the output characteristics of the vibrator 11 can be matched with the output characteristics of the vibrators 12 and 13. In this case, for example, the moving body 10 may be driven by the vibrator 11 and the vibrator 13 with the direction orthogonal to the driving direction of the vibrator 12 as the target moving direction of the moving body 10. However, the vibrator 12 is driven in the B mode.

  Thereby, it is determined whether or not the output characteristic of the vibrator 11 matches the output characteristic of the vibrator 13, and the frequencies of the drive voltages VA and VB applied to the vibrator 11 are defined according to the determination result. The value of the parameter α11 to be changed is changed.

  Further, the moving body 10 is driven by the vibrator 11 and the vibrator 12 with the direction orthogonal to the driving direction of the vibrator 13 as the target moving direction of the moving body 10, thereby outputting the three vibrators 11 to 13. It is possible to verify whether the characteristics match.

  In this way, the correction of the output characteristics for matching the output characteristics of the vibrators 11 to 13 is performed by changing the frequencies (parameters α11 to α13) of the drive voltages VA and VB. When the moving body 10 is actually moved, the corresponding vibrators 11 to 13 are driven with the driving voltages VA and VB having the changed frequencies. However, the voltage values of the drive voltages VA and VB applied to the vibrators 11 to 13 are not changed but are held at preset values. As a result, the driving of the vibrators 11 to 13 can be stably controlled by controlling the phase difference between the driving voltages VA and VB.

  In the above example, the frequencies of the drive voltages VA and VB (values of the parameters α11 to α13) are changed to match the output characteristics of the vibrators 11 to 13, but instead, the drive voltages VA, The voltage value of VB (values of parameters γ11 to γ13) may be changed.

  In this case, as shown in FIG. 12, the output characteristics (curve Out12) of the vibrator 12 are corrected by changing the voltage values without changing the frequencies of the drive voltages VA and VB applied to the vibrator 12. The Specifically, the value of the parameter γ12 is changed so that the voltage values of the drive voltages VA and VB applied to the vibrator 12 are increased. Accordingly, the output characteristic of the vibrator 12 when the drive voltage VA and VB having the frequency f0 and the frequency f0 are applied is represented by a curve Out12 ′, and the output characteristic of the vibrator 13 (curve Out13) is shown. Match. That is, by making the moving direction obtained by the position sensors 21, 22, 23 coincide with the Y direction, the magnitudes of the driving forces of the vibrators 12, 13 can be made the same.

  The same effect can be obtained by changing the pulse widths of the A phase, / A phase, B phase, and / B phase.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 13 illustrates each of the controls controlled when the vibrators 11 to 13 are driven by the driving voltages VA and VB having the frequency f3 and the voltage value V3 to rotate the moving body 10 in the θ direction in the second embodiment of the present invention. It is a figure which shows the phase difference between the drive voltages VA and VB of the vibrator | oscillators 11-13. FIG. 14 is a diagram showing the relationship between the phase difference between the drive voltages VA and VB applied to the vibrators 11 to 13 and the speed. FIG. 15 is a diagram illustrating the relationship between the frequency and the speed between the drive voltages VA and VB applied to the vibrators 11 to 13, respectively. FIG. 16 shows the phase difference and the frequency f4 and voltage value applied to the vibrator 13 when the control is performed by performing a certain operation between the drive voltage VA and VB of the frequency f3 and voltage value V3 applied to the vibrators 11 and 12. It is a figure which respectively shows the phase difference when it controls by making a certain operation | movement between the drive voltages VA and VB of V3. The present embodiment has the same configuration as the configuration of the first embodiment, and the same reference numerals are used in the description of the present embodiment.

  In the first embodiment, the corresponding vibrators 11 to 13 are driven to move the moving body 10 straight in a predetermined direction such as the Y direction. Based on the movement result, each of the vibrators 11 to 13 is moved. A case has been described in which it is determined whether or not the output characteristics match.

  In contrast, in the present embodiment, each transducer 11 to 13 is based on the control amount of the phase difference (β11 to β13) of the drive voltages VA and VB for controlling the drive force of each transducer 11 to 13. It is determined whether or not the output characteristics match. Then, according to the determination result, the frequencies (parameters α11 to α13) or voltage values (γ11 to γ) of the drive voltages VA and VB for the transducers 11 to 13 are matched so that the output characteristics of the transducers 11 to 13 match. γ13) is changed.

  For example, when the moving body 10 is rotated in the θ direction (shown in FIG. 9), the driving forces of the vibrators 11 to 13 need to be the same. Here, it is assumed that drive voltages VA and VB having the same frequency f3 and the same voltage value V3 are applied to the vibrators 11 to 13, respectively. Further, it is assumed that the resonance frequencies of the vibrators 11 and 12 coincide with frequencies in the vicinity of the frequency f3 of the drive voltages VA and VB, and the resonance frequency of the vibrator 13 is significantly different from the frequency f3.

  In such a case, as shown in FIG. 13, the level between the driving voltages VA and VB applied to the vibrators 11 to 13 is set so that the driving forces of the vibrators 11 to 13 are the same. The phase difference (values of parameters β11 to β13) is controlled. As can be seen from FIG. 13, the control amount of the phase difference between the drive voltages VA and VB of the vibrator 13 may exceed π / 2 (rad).

  Here, if the target rotational speed in the θ direction of the moving body 10 is 50 mm / sec, for example, as shown in FIG. 14, the phase difference between the drive voltages VA and VB at the frequency f3 for each transducer 11 and 12 is Each is controlled to about 28π / 180 (rad). On the other hand, the phase difference between the drive voltages VA and VB at the frequency f3 with respect to the vibrator 13 is controlled to about π / 2 (rad). This is because the resonance frequencies of the vibrators 11 and 12 and the vibrator 13 are different, and the output characteristics of the vibrator 13 with respect to the vibrators 11 and 12 are different.

  When the phase difference between the driving voltages VA and VB is π / 2 (rad), the magnitude of the driving force generated by the vibrator is maximized (the rotational speed of the moving body 10 is maximized), which exceeds this. In the case of the phase difference, on the contrary, the driving force becomes small (the rotational speed becomes slow). Therefore, in the case of the vibrator 13, the phase difference between the drive voltages VA and VB is controlled by a value in the vicinity of π / 2 (rad), so that the driving force of the vibrator 13 is driven by the other vibrators 11 and 12. It is difficult to control so as to stably maintain a state equal to the magnitude of the force. Therefore, in order to stably perform control for maintaining the rotational speed of the moving body 10 at a desired speed, the control amount of the phase difference between the drive voltages VA and VB is changed from −π / 2 to π. It is preferable to vary within a range up to / 2 (rad).

  When there is a large difference between the control amounts of the phase difference between the drive voltages VA and VB for each of the vibrators 11 to 13, this means that the output characteristics of the vibrators 11 to 13 are greatly different.

  In the case of the phase difference shown in FIG. 14, the control amount of the phase difference between the drive voltages VA and VB for each of the vibrators 11 and 12 is almost the same. The Regarding the vibrator 13, the control amount of the phase difference between the drive voltages VA and VB is greatly different from the control amount of the phase difference between the drive voltages VA and VB of the vibrators 11 and 12. It is determined that the output characteristics of the vibrators 11 and 12 do not match.

  In this case, for example, as shown in FIG. 15, without changing the voltage values V3 of the drive voltages VA and VB for the vibrator 13 so that the output characteristics of the vibrator 13 coincide with the output characteristics of the vibrators 11 and 12. The frequency (value of parameter α13) is changed from frequency f3 to frequency f4. Accordingly, as shown in FIG. 16, the control amount of the phase difference between the drive voltages VA and VB for the vibrator 13 is within the range of −π / 2 to π / 2 (rad), and the vibrators 11, The control amount of the phase difference between the twelve drive voltages VA and VB is not significantly different.

  Thus, the output characteristics of the vibrators 11 to 13 are matched by changing the frequency, and the drive control of the vibrators 11 to 13 is performed within the range of −π / 2 to π / 2 (rad) and substantially the same. A stable control can be performed with a controlled amount of phase difference between a certain drive voltage VA and VB.

  Similarly to the first embodiment, instead of the drive voltages VA and VB (the values of the parameters α11 to α13), the drive voltages VA and VB (the values of the parameters γ11 to γ13), or You may make it change each pulse width of A phase, / A phase, B phase, / B phase.

  Further, when the control gain at the time of control is changed, the control amount of the phase difference between the drive voltages VA and VB with respect to the deviation changes, and the relationship between the phase difference between the drive voltages VA and VB and the speed as shown in FIG. 14 is shown. The slope of the straight line can be changed. That is, by changing the control gain, the output characteristics of the vibrators 11 to 13 can be corrected so as to match.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIGS. FIG. 17 shows the driving of the vibrators 11 to 13 when it is determined whether or not the output characteristics of the vibrators 12 and 13 match in the multi-degree-of-freedom driving device according to the third embodiment of the present invention. It is a figure which shows a state. FIG. 18 is a diagram showing the control amount of the phase difference between the drive voltages VA and VB applied to the vibrators 12 and 13, respectively. The present embodiment has the same configuration as the configuration of the first embodiment, and the same reference numerals are used in the description of the present embodiment.

  In the first embodiment, when it is determined whether or not the output characteristics of the vibrators 12 and 13 are the same, the vibrator 11 is driven in the B mode (vertical vibration), Each vibrator 12, 13 is driven.

  On the other hand, in the present embodiment, as shown in FIG. 17, when determining whether or not the output characteristics of the vibrators 12 and 13 are the same, the drive of the vibrator 11 is stopped. In this state, the vibrators 12 and 13 are driven. Here, the vibrators 12 and 13 are in a state in which the moving body 10 is stationary because the combined driving force is balanced with the frictional force generated between the protrusion 19 of the vibrator 11 and the moving body 10. Driven to hold. Specifically, the driving force (vector Ms) obtained by synthesizing the driving force (vector M12) of the vibrator 12 and the driving force (vector M13) of the vibrator 13 becomes the driving force acting on the moving body 10. If this driving force (vector Ms) is balanced with the frictional force (vector Fs) generated between the protrusion 19 of the vibrator 11 and the moving body 10, the moving body 10 is held stationary. That is, in order to maintain the stationary state of the moving body 10, the drive voltages VA and VB applied to the vibrators 12 and 13 are set so that the magnitudes of the drive forces of the vibrators 12 and 13 are the same. The phase difference is controlled. Then, based on the control amount of the phase difference between the drive voltages VA and VB applied to the vibrators 12 and 13, it is determined whether or not the output characteristics of the vibrators 12 and 13 match.

  For example, as shown in FIG. 18, it is assumed that the phase difference between the drive voltages VA and VB applied to the vibrators 12 and 13 is controlled. The drive voltages VA and VB applied to the vibrators 12 and 13 are drive voltages having the same frequency and the same voltage value. The phase difference between the driving voltages VA and VB of the vibrator 12 is controlled to a value in the vicinity of π / 2 (rad), and the phase difference between the driving voltages VA and VB of the vibrator 13 is in the vicinity of −35π / 180 (rad). Controlled by value. This is because, for example, because the resonance frequency of the vibrator 12 and the resonance frequency of the vibrator 13 are greatly different, each vibration when the vibrators 12 and 13 are driven with the drive voltages VA and VB having the same frequency and the same voltage value. This means that the output characteristics of the children 12 and 13 are different.

  Therefore, the frequency (value of parameter α13) or voltage value (γ13 value) of the drive voltages VA and VB applied to the vibrator 13 is changed so that the output characteristics of the vibrator 13 match the output characteristics of the vibrator 12. Is done.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described with reference to FIG. FIG. 19 shows the driving of the vibrators 11 to 13 when it is determined whether or not the output characteristics of the vibrators 12 and 13 are the same in the multi-degree-of-freedom driving device according to the fourth embodiment of the invention. It is a figure which shows a state. The present embodiment has the same configuration as the configuration of the first embodiment, and the same reference numerals are used in the description of the present embodiment.

  The multi-degree-of-freedom driving device according to the present embodiment is incorporated in an imaging device and used as a device for moving an imaging element such as a CCD (Charged Coupled Device) in each of X, Y, and θ directions. In this case, an image sensor is mounted on the moving body 10.

  In such an application, gravity may act on the moving body 10 in the vertical direction (−Y direction). Therefore, in order to hold the moving body 10 in a stationary state, the vibrator 11 is driven in the B mode (only the vertical vibration mode), and the vibrators 12 and 13 are driven in the + Y direction against gravity. It is necessary to drive so that the force always acts on the moving body 10. That is, the driving force (vector Ms) obtained by combining the driving force of the vibrator 12 (vector M12) and the driving force of the vibrator 13 (vector M13) is the driving force in the + Y direction that acts on the moving body 10. If this driving force (vector Ms) is balanced with gravity, the moving body 10 is held stationary.

  In this case, the phase difference between the driving voltages VA and VB applied to the vibrators 12 and 13 is controlled so that the magnitudes of the driving forces of the vibrators 12 and 13 are the same. In this control, if there is a large difference between the control amounts of the phase differences between the drive voltages VA and VB applied to the vibrators 12 and 13, it is determined that the output characteristics of the vibrators 12 and 13 do not match. The Here, the drive voltages VA and VB applied to the vibrators 12 and 13 are drive voltages having the same frequency and the same voltage value.

  For example, the phase difference between the driving voltages VA and VB of the vibrator 12 is controlled to a value in the vicinity of π / 2 (rad), and the phase difference between the driving voltages VA and VB of the vibrator 13 is in the vicinity of −35π / 180 (rad). Is controlled to the value of. This is because, for example, because the resonance frequency of the vibrator 12 and the resonance frequency of the vibrator 13 are greatly different, each vibration when the vibrators 12 and 13 are driven with the drive voltages VA and VB having the same frequency and the same voltage value. This means that the output characteristics of the children 12 and 13 are different.

  Therefore, the frequency (value of parameter α13) or voltage value (γ13 value) of the drive voltages VA and VB applied to the vibrator 13 is changed so that the output characteristics of the vibrator 13 match the output characteristics of the vibrator 12. Is done. Thereby, the control amount of the phase difference between the drive voltages VA and VB when the vibrators 12 and 13 are driven becomes substantially the same, and stable control can be performed.

DESCRIPTION OF SYMBOLS 10 Mobile body 11,12,13 Vibrator 21,22,23 Position sensor 31,32,33 Scale part 50 Control part 51 Drive part 53,54,55 Drive pulse generator 56,57,58 Switching circuit 59 Power supply circuit

Claims (5)

A plurality of vibrators driven by drive voltages generated based on values set in a plurality of parameters, and movements that are in contact with each of the vibrators so as to be movable in multiple directions by the plurality of vibrators With body,
Wherein the plurality of parameters include a phase difference which is a first parameter value which is varied according to the driving of the corresponding vibrator is set, and a second parameter different from the parameters of the first,
Whether the output characteristics of the vibrators match with each other based on the value of the first parameter of the voltage applied to each of the vibrators so that substantially the same speed is generated in the vibrators . Determining means for determining whether or not,
If it is determined by the determining means that the output characteristics of the transducers do not match, the first and second transducers have the output characteristics matched so that the output characteristics of the driven transducers match. A multi-degree-of-freedom drive device comprising: a changing unit that changes a value set in the parameter of 2. Wherein the first parameter, multi-degree-of-freedom drive device according to claim 1, values for defining the phase difference between the A-phase and B phase of the driving voltage and wherein the set Turkey.   The multi-degree-of-freedom drive device according to claim 1, wherein the second parameter is a parameter in which a value for defining a frequency of the drive voltage is set.   The multi-degree-of-freedom drive device according to claim 1, wherein the second parameter is a parameter in which a value for defining a voltage value of the drive voltage is set. 3. The multi-degree-of-freedom driving device according to claim 1, wherein each of the plurality of vibrators is configured to generate a driving force by vibration obtained by combining vibrations of two modes.

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