JP2004201432A - Ultrasonic motor device and electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ultrasonic motor device capable of being improved in the endurance of a vibrator that is repeatedly positioned. <P>SOLUTION: It is based on the premise that the ultrasonic motor device 1 comprises a control unit 40 that controls the application of the high-frequency voltage of the vibrator 23 to a piezoelectric body 22; actuates and stops, and normally rotates and reversely rotates a moving body 24 that is in pressure-contact with the vibrator; compares a position signal from a position sensor 30 that generates the position signal of the moving body and a target position; and positions the position of the moving body so as to be the target position. A forcible rotation control unit 40b that determines whether or not a pre-inputted forcible rotation condition is satisfied and forcibly rotates the moving body 24 with one or more turns after the establishment of the condition. By forcibly rotating the moving body 24, a friction material 24a that forms the pressure-contact face of the moving body 24 in friction-contact with the vibrator 23 is made uniform as a whole, and the surface of the friction material is kept almost uniform. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an ultrasonic motor device that converts the expansion and contraction motion of a piezoelectric body into a rotary motion and an electronic device equipped with the motor device, and more particularly to an ultrasonic motor device capable of taking measures against wear caused by positioning of a rotating moving body. And electronic equipment.
[0002]
[Prior art]
The ultrasonic motor fixes a vibrating body in which a polarized piezoelectric element is adhered to the back surface to a center axis of a fixed base, and incorporates an enlargement mechanism for expanding the displacement of the vibrating body rotatably around the center axis. The moving body is brought into contact with the moving body via a friction material, and the moving body is pressed against the vibrating body by a pressure spring. In this ultrasonic motor, a high-frequency voltage is applied to a piezoelectric element to generate flexural vibration in a vibrating body, thereby rotating a pressed moving body by frictional force (for example, see Patent Document 1). ).
[0003]
[Patent Document 1]
JP-A-2000-139089 (paragraph 0002, FIGS. 1 to 3)
[0004]
[Problems to be solved by the invention]
This type of ultrasonic motor has the following features. It has high torque at low speed. Has a large holding torque when no current is applied. High responsiveness and controllability. No magnetic effect. Small size and light weight are possible. And the operating noise is extremely low. Therefore, the ultrasonic motor can be suitably used as a drive source of a positioning unit of various electronic devices. For example, the present invention can be used for a pointing device for controlling a movement at a fixed angle, a mirror angle control, a pickup drive of a head of information equipment, and the like.
[0005]
The positioning of the ultrasonic motor is performed by a control device in which a target position is set in advance and a position sensor that detects a current position of a moving body driven by a vibrating body of the ultrasonic motor. These ultrasonic motor, control device, and position sensor constitute an ultrasonic motor device. When the moving body of the ultrasonic motor rotates, the position sensor is a rotary encoder. The control device constantly monitors the current position signal of the moving object generated by the position sensor, monitors whether the current position of the moving object is the target position, and executes the following positioning control. When detecting that the current position of the moving body has reached the target position, the control device checks whether or not there is overshoot. When the control device determines that there is an overshoot, it immediately reverses the ultrasonic motor. The control device terminates the positioning control when it determines that there is no overshoot, that is, when it determines that the moving body has entered a settling state in which it holds the target position.
[0006]
As described above, if there is an overshoot after the moving body reaches the target position, the ultrasonic motor is immediately rotated in the reverse direction. Since this overshoot is an unavoidable phenomenon, this reverse operation is repeatedly performed in the positioning control. As a result, the overshoot amount (the amount of overshoot deviation from the target position) gradually decreases and finally converges to zero. That is, the ultrasonic motor enters a settling state. It is desirable that the time from when the target position is first reached to the stabilization state, that is, the settling time, be short.
[0007]
By the way, Patent Document 1 does not describe the following problem associated with positioning control that is repeatedly performed in which the ultrasonic motor reversely rotates with respect to the previous rotation in order to converge the overshoot with respect to the target position.
[0008]
That is, the friction material of the moving body is pressed against the displacement enlarging mechanism (a plurality of projections) of the vibrating body by the pressure spring. As a result, a region (referred to as a positioning region) in contact with the displacement enlarging mechanism including the target position for positioning the friction material is intensively and repeatedly rubbed by the displacement enlarging mechanism. Proceed ahead of area. As a result, the surface state of the pressure contact surface made of the friction material of the moving body becomes uneven. When the surface condition deteriorates from the initial state in this way, the settling time changes along with the performance of converting the vibration of the displacement magnifying mechanism into the rotation of the moving object according to the state, and the positioning accuracy of the moving object and the motor efficiency are changed. Phenomenon occurs.
[0009]
Therefore, when the moving body of the ultrasonic motor of Patent Document 1 is used by positioning it so as to stop at a certain fixed position, or depending on the number of overshoots, etc., the positioning control of the moving body rotated as described above is performed. Accordingly, it is inevitable that the settling time changes. As a result, when the settling time takes a long time, the wear of the positioning area including the target position for positioning and in contact with the displacement enlarging mechanism is further promoted, and the life of the ultrasonic motor may be shortened. For this reason, in an electronic device equipped with an ultrasonic motor, there is a possibility that the life of the ultrasonic motor is shortened, that is, there is a possibility that a malfunction may occur due to durability.
[0010]
An object of the present invention is to provide an ultrasonic motor device that can improve the durability of a moving body that is repeatedly positioned, and an electronic apparatus including the ultrasonic motor device.
[0011]
[Means for Solving the Problems]
The present invention controls the application of a high-frequency voltage to the piezoelectric body of the vibrating body, starts and stops the moving body that is in pressure contact with the vibrating body, performs forward rotation and reverse rotation, and also outputs a position signal of the moving body. It is assumed that the ultrasonic motor device includes a control device that performs positioning so that the position of the moving body becomes the target position by comparing the position signal from the position sensor that generates the target and the input target position.
[0012]
In order to solve the above problem, a control device is provided with a forced rotation control unit, and the control unit determines whether a previously input forced rotation condition is satisfied, and the forced rotation condition is satisfied. Later, the moving body is forcibly rotated one or more times continuously. Here, the reason why the rotation is one rotation or more is that if the target position for positioning is invariable, if it is one rotation or less, the state of the entire pressure contact surface of the moving body may not be uniform.
[0013]
In a preferred aspect of the present invention, the forced rotation condition is satisfied when the time required for the positioning exceeds a preset settling time. Similarly, when a predetermined positioning time that is set in advance in consideration of a specified time and a constant variation rate with respect to the specified time is deviated, the forced rotation condition is satisfied. Similarly, when the positioning is performed exceeding a preset number of times of performing the positioning, the forced rotation condition is satisfied. Similarly, immediately after the power is turned on, the forced rotation condition is satisfied. Similarly, immediately before the power is turned off, the forced rotation condition is satisfied. Similarly, when the number of overshoots at the time of positioning exceeds a predetermined number of times, the forced rotation condition is satisfied. Similarly, when the amount of deviation of the overshoot at the time of the positioning from the target position exceeds a predetermined value, the forced rotation condition is satisfied.
[0014]
Further, in a preferred embodiment of the present invention, the forcible rotation can be performed by rotating the moving body clockwise. Similarly, the forcible rotation can be performed by rotating the moving body counterclockwise. Similarly, the forced rotation can be performed by rotating the moving body at least once in the clockwise and counterclockwise directions.
[0015]
In the present invention, when the forced rotation condition input in advance to the forced rotation control unit is satisfied, the moving body is forcibly continuously rotated one or more rotations thereafter. Each time the forced rotation is performed, the entire pressure contact surface of the moving body that is in frictional contact with the vibrating body is leveled.
[0016]
In order to solve the above-mentioned problems, the present invention provides a target position changing unit in a control device, and the changing unit determines whether or not a pre-input forced rotation condition is satisfied. After the rotation condition is satisfied, the target position is deviated from the positioning area including the target position on the moving body and in contact with the vibrating body, and the area having less wear than the positioning area is the positioning area. You may make it change.
[0017]
In the present invention, when the forcible rotation condition input in advance to the target position changing unit is satisfied, the moving body is moved so that an area that has been out of the positioning area on the moving body thereafter is used as a new positioning area. Is changed. As a result, until the next forced rotation is performed or until the end of the life, the moving body can be positioned by bringing the vibrating body into pressure contact with the area newly set as the positioning area as described above.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. FIG. 2 is a block diagram showing the ultrasonic motor device 1 according to the first embodiment. The ultrasonic motor device 1 includes an ultrasonic motor 2, a position sensor 30, and a control device 40. The rotation of the ultrasonic motor device 1 is controlled by processing a position signal output from the position sensor 30 by the control device 40, and thereby has a function of positioning a moving body to be described later at substantially the same target position. Have.
[0019]
The ultrasonic motor 2 vibrates the vibrating body 23 to which the piezoelectric body 22 is joined, the moving body 24 which is disposed so as to rotate clockwise and counterclockwise by the vibration of the vibrating body 23, and functions as a rotor. The piezoelectric device 22 includes a pressure unit 25 that functions as a pressure mechanism that presses and contacts the body 23, a pair of electrodes 21a and 21b that apply a high-frequency voltage to the piezoelectric body 22, and an oscillation drive circuit 10 that generates the high-frequency voltage. The electrode 21a is for clockwise rotation, and the electrode 21b is for counterclockwise rotation.
[0020]
FIG. 1 is a sectional view of a main part of the ultrasonic motor 2. As shown in FIG. 2, the moving body 24 is rotatably supported on a shaft 27 via a bearing 28 so as to be rotatable. The moving body 24 has a friction material 24a bonded to the back surface (the lower surface in FIG. 2). The friction material 24a functions as a friction contact surface (also referred to as a pressure contact surface) with the vibrating body 23, and is more easily worn than a protrusion 26 described later. As the friction material 24a, for example, a composite plastic containing carbon fiber can be suitably used. The friction material 24a can be removed and replaced at the time of maintenance or the like.
[0021]
The shaft 27 is erected on a support plate (also called a fixed base) 29. The vibrating body 23 is formed in a disk shape by, for example, an aluminum alloy, and is coaxially fixed to the shaft 27. On the surface (the upper surface in FIG. 1) of the vibrating body 23, a plurality of, for example, six projections 26 (only two are shown in FIG. 1) functioning as a displacement magnifying mechanism are integrally formed.
[0022]
A piezoelectric body 22 made of piezoelectric ceramics such as zinc zirconate titanate is bonded to the back surface (the lower surface in FIG. 1) of the vibrating body 23. A pair of electrodes formed in a predetermined electrode pattern, that is, a clockwise rotation electrode 21a and a counterclockwise rotation electrode 21b are arranged on the back surface (the bottom surface in FIG. 1) of the piezoelectric body 22, and lead wires 21d are provided respectively. And 21e are electrically connected to the drive circuit. A common electrode 21 c (not shown) is provided on the upper surface side of the piezoelectric body 22, that is, a surface in contact with the vibrating body 23, and is electrically connected to a lead wire 21 f via a shaft 27.
[0023]
The spring 25, which is a pressurizing means, is sandwiched in a compressed state between a spring receiver 27a attached to the shaft 27 so as to cover the tip of the shaft 27 and an inner ring of a bearing 28 slidable with respect to the shaft 27, for example. Is provided. The moving body (b) is pressed against the vibrating body 23 by the elastic force of the spring 25, and the friction material 24a is pressed against the distal end surfaces of the plurality of projections 26.
[0024]
As shown in FIG. 2, the oscillation drive circuit 10 includes a resistor 13, a resistor 14, a capacitor 15, and a capacitor 16. The oscillation drive circuit 10 includes a start / stop inverter 11, a clockwise rotation buffer 12a, and a counterclockwise rotation buffer 12b. The oscillation drive circuit 10 forms a Colpitts oscillation circuit type self-excited oscillation circuit by the above-described circuit elements, the piezoelectric body 22 and the vibration body 23 as vibrators. This self-excited oscillation circuit is described in detail in the paper "Development of a micro ultrasonic motor using self-excited drive" described in the Journal of the Japan Society of Precision Engineering (Vol. 64, No. 8, pages 1117 to 1121). Is disclosed.
[0025]
The position sensor 30 is, for example, a rotary encoder, and constantly detects the current position of the moving body 24, and provides an output signal thereof to the control device 40. As illustrated in FIG. 1, the position sensor 30 has a disk-shaped encoder scale 31, a light-emitting element 32, and a photoelectric conversion element 33. A large number of slits 34 are formed in the circumferential portion of the encoder scale 31 at equal intervals in the circumferential direction. The number of the slits 34 is a number corresponding to the resolution required in the positioning control for the moving body 24. The encoder scale 31 is attached and arranged on the surface of the moving body 24, and its peripheral portion protrudes from the moving body 24. The periphery of the encoder scale 31 is arranged between the light emitting element 32 and the photoelectric conversion element 33 so that the light beam passes through the slit 34. The photo interrupter having the light emitting element 32 and the light receiving element 33 is attached to the support plate 29.
[0026]
The control device 40 includes a motor control unit 40a and a forced rotation control unit 40b. In the motor control unit 40a, a target position for stopping the moving body 24 at a predetermined position is previously input and set by an input unit (not shown). The setting of the target position can be performed by constantly inputting the target position of the moving body 24 to the control device 40 from an external device (not shown). The motor control unit 40a compares the input target position with the current position (current position signal) output from the position sensor 30 so that the current position of the moving body 24 always matches the target position. It has a function of performing feedback control (positioning control).
[0027]
This feedback control is performed by giving a control command signal to the oscillation drive circuit 10 from the motor control unit 40a of the control device 40. The control command signals are a start command signal, a stop command signal, a clockwise rotation command signal, and a counterclockwise rotation command signal, and these are an ON signal and an OFF signal. The start command signal and the stop command signal are given to the inverter 11. The clockwise rotation command signal is provided to a clockwise rotation buffer 12a, and the counterclockwise rotation command signal is provided to a counterclockwise rotation buffer 12b.
[0028]
The start / stop inverter 11, the clockwise rotation buffer 12a, and the counterclockwise rotation buffer 12b are circuit components such as a tri-state or three-state IC. Each of these has a control terminal in addition to an input terminal and an output terminal, and can output two voltages of HIGH and LOW by a control command signal input to the control terminal. A high impedance state can be set between them.
[0029]
The forced rotation control unit 40b of the control device 40 maintains the surface state of the friction material 24a forming the pressure contact surface substantially uniformly separately from the positioning control by the motor control unit 40a, that is, regardless of the positioning of the moving body 24. It is provided in order to. Forced rotation conditions are previously input and set in the forced rotation control unit 40b by the input means (not shown). The setting of the forced rotation condition can also be performed by constantly inputting the forced rotation condition to the motor control unit 40a of the control device 40 from an external device (not shown).
[0030]
The forced rotation condition is a condition for forcibly rotating the moving body 24. In the first embodiment, the forced rotation condition is set when the positioning of the moving body 24 fails. Here, the positioning failure means that when positioning the moving body 24 at the target position, the positioning operation is performed beyond the settling time without the positioning operation being completed within a predetermined positioning time (settling time) set in advance. It means that the state has been reached.
[0031]
To determine the positioning failure, the forced rotation control unit 40b has a comparator (not shown). A predetermined settling time is set in this comparator as a reference value (specified value). The forced rotation control unit 40b determines whether the value of the position signal of the moving body 24 supplied from the position sensor 30 to the comparator exceeds a reference value. It has a function of forcibly rotating the moving body 24 one or more times continuously in accordance with the timing of the rotation.
[0032]
Here, the number of forced rotations, the time during which the forced rotation is performed, and the time at which the forced rotation is performed are set in the control device 40 in advance. In the forced rotation, the moving body 24 is continuously rotated one or more times, and the number of rotations at that time can be appropriately determined according to the contents of the forced rotation condition. Further, the rotation of the moving body 24 at the time of the forced rotation may be clockwise rotation (CW) or counterclockwise rotation (CCW). In addition, the rotation of the moving body 24 may be performed at least once clockwise and counterclockwise. In some cases, one of these is set in the forced rotation control unit 40b.
[0033]
When to perform the forced rotation, one of the following two methods can be selected. First, when the positioning of the moving body 24 fails, that is, when the forced rotation control unit 40b determines that the forced rotation condition is satisfied, the forced rotation is executed immediately after the completion of the positioning operation. In the second case, the forced rotation is executed immediately before the first power-off after the positioning of the moving body 24 fails or immediately after the first power-on after the completion of the positioning operation. When the forced operation is performed at the second time, it is preferable because unnaturalness in operation of the ultrasonic motor device 1 can be apparently suppressed.
[0034]
The electronic device 3 shown in FIG. 6 includes the ultrasonic motor device 1 having the above-described configuration mounted thereon, a transmission mechanism 4, and an output mechanism 5.
[0035]
The transmission mechanism 4 is movable in conjunction with the moving body 24, and may use, for example, a transmission wheel such as a gear wheel or a friction wheel. The transmission mechanism 4 can be omitted, and the output mechanism 5 can be linked directly to the moving body 24. It is also possible to attach an output shaft to the moving body 24 and have a power transmission mechanism for transmitting torque from the output shaft. In this case, the ultrasonic motor device 1 itself functions as a drive mechanism. be able to.
[0036]
As the output mechanism 5, for example, a pointer, a pointer driving mechanism, a display plate such as a calendar, or a display plate driving mechanism in an electronic timepiece can be used. Similarly, in copiers and printers, it is used as a mechanism to move a mirror that changes the direction of laser light. In cameras and video cameras, it is used as a shutter drive mechanism, aperture drive mechanism, lens drive mechanism, film winding mechanism, etc. Can be used. Similarly, in a measuring instrument, a manufacturing apparatus, and an optical sensor using a laser beam, it can be used for a mechanism for driving a slit plate or a filter that blocks and transmits light or transmits only a specific wavelength. Similarly, a contact mechanism or a gap plate for changing a resistance value or a capacitance value can be used for a volume or the like of an audio device. Similarly, a pickup mechanism can be used for a hard disk or an optical disk.
[0037]
In the ultrasonic motor device 1 having the above-described configuration, when a high-frequency voltage is applied between the clockwise rotation electrode 21a or the counterclockwise rotation electrode 21b and the common electrode 21c, a periodic movement is caused by the expansion and contraction movement of the piezoelectric body 22. Vibration is generated in the vibrating body 23. This periodic vibration is a standing wave, and the periodic vibration of the vibrating body 23 is transmitted as power to the moving body (b) that is pressed against the plurality of protrusions 26 by the spring 25.
[0038]
The moving body 24 is frictionally driven by the vibration wave generated in the vibrating body 23 through the contact between the predetermined electrode pattern and the plurality of protrusions 26 formed at the predetermined spacing and arrangement, and is clockwise or counterclockwise. Rotated. In this case, when a high-frequency voltage is applied between the clockwise rotation electrode 21a and the common electrode 21c, the moving body 24 rotates clockwise. When the high frequency voltage is applied between the counterclockwise rotation electrode 21b and the common electrode 21c, the moving body 24 rotates counterclockwise. Since the configuration and operation of such a standing wave type ultrasonic motor device are disclosed in Japanese Patent Application Laid-Open No. H11-55971, a detailed description thereof will be omitted.
[0039]
The positioning control in the ultrasonic motor device 1 is performed according to steps 101 to 105 of the flowchart of FIG. That is, the motor control unit 40a of the control device 40 constantly monitors the current position signal from the position sensor 30 and monitors whether the current position of the moving body 24 is the target position (step 101). Accordingly, when it is detected that the current position of the moving body 24 has reached the target position after the positioning is started, the motor control unit 40a generates a stop command signal and gives it to the oscillation drive circuit 10 (step 102). Subsequently, the motor control unit 40a checks whether or not there is an overshoot (step 103). If it is determined that there is an overshoot, the motor control unit 40a holds the stop command signal as it is for the stop command holding time t (step 103). 103). When the stop command holding time t has elapsed, the motor control unit 40a supplies a reverse rotation command signal to the oscillation drive circuit 10 to cause the moving body 24 to perform a reverse rotation operation (step 105). After step 105, the process returns to step 101, and the above operation is repeated. Then, in step 103, when the motor control unit 40a determines that there is no overshoot, the position correction operation ends.
[0040]
The above positioning control operation will be described in more detail together with the states of the inverter 11, the buffer 12a, and the buffer 12b.
[0041]
(B) When the moving body 24 functioning as an overnight has overshot during the clockwise rotation, the states of the invar 11, the buffers 12a, and 12b change as follows. That is, when the moving body 24 is rotating clockwise, the motor control unit 40a supplies ON, ON, and OFF control signals to the respective control terminals of the inverter 11, the buffer 12a, and the buffer 12b. Therefore, the inverter 11 is enabled, the buffer 12a is enabled, and the buffer 12b is disabled. Accordingly, the high frequency voltage from the oscillation drive circuit 10 is supplied to the piezoelectric body 22 from the electrode 21a and the common electrode 21c, and the moving body 24 is rotating clockwise.
[0042]
In this state, when the moving body 24 reaches the target position (Step 101), the motor control unit 40a generates a stop command signal at that moment (Step 102), and supplies an OFF control signal to the control terminal of the inverter 11. As a result, the inverter 11 is switched to the disable state, and the supply of the high-frequency voltage from the oscillation drive circuit 10 to the piezoelectric body 22 is stopped. Even if the supply of the high-frequency voltage to the piezoelectric body 22 is stopped, the moving body 24 stops completely after rotating slightly in the clockwise direction due to residual vibration and inertia. This slight rotational movement amount is the largest during the first overshoot, becomes smaller than the previous one when the overshoot due to the reverse rotation continues, becomes smaller each time overshoot is repeated, and finally converges to the target position and enters a settled state. Become.
[0043]
Subsequent to step 102, the motor control unit 40a determines whether or not the position of the moving body 24 has exceeded the target position. The signal is held as it is (step 103).
[0044]
When the moving body 24 exceeds the target position, slightly rotates clockwise due to residual vibration and inertia, and then stops completely for a while, the stop command holding time t elapses. The motor control unit 40a generates a forward / reverse switching command signal at an arbitrary moment within the stop command holding time t, and supplies OFF and ON control signals to respective control terminals of the buffer 12a and the buffer 12b. Then, the buffer 12a switches to the disabled state, and the buffer 12b switches to the enabled state. Therefore, when the stop command holding time t is reached (step 104), the motor control unit 40a generates a stop command release signal at that moment, and gives an ON control signal to the control terminal of the inverter 11. Then, the inverter 11 is switched to the enable state, the supply of the high-frequency voltage from the oscillation drive circuit 10 to the piezoelectric body 22 is restarted, and the moving body 24, which is a short time, is rotated counterclockwise (step 105).
[0045]
Next, when the moving body 24 overshoots during the counterclockwise rotation, the motor control unit 40a supplies ON, OFF, and ON control signals to respective control terminals of the inverter 11, the buffer 12a, and the buffer 12b. Therefore, the inverter 11 is in the enable state, the buffer 12a is in the disable state, and the buffer 12b is in the enable state. The high frequency voltage from the oscillation drive circuit 10 is supplied to the piezoelectric body 22 from the electrode 21b, and the movement is almost complete. The body 24 is rotating counterclockwise.
[0046]
In this state, when the moving body 24 reaches the target position (Step 101), the motor control unit 40a generates a stop command signal at that moment (Step 102), and supplies an OFF control signal to the control terminal of the inverter 11. . Then, the inverter 11 is switched to the disable state, and the supply of the high frequency voltage from the oscillation drive circuit 10 to the piezoelectric body 22 is stopped. Even if the supply of the high-frequency voltage to the piezoelectric body 22 is stopped, the moving body 24, which is still in a state, stops slightly after rotating slightly clockwise due to residual vibration and inertia.
[0047]
Subsequent to step 102, the motor control unit 40a checks whether or not the position of the moving body 24 has exceeded the target position, and when it is determined that there is overshoot, the stop command signal is output for the stop command holding time t. Is held as it is (step 103).
[0048]
If the moving body 24, which is one night, exceeds the target position, slightly rotates clockwise due to residual vibration and inertia, and then stops completely for a while, the stop command holding time t elapses. The motor control unit 40a generates a forward / reverse switching command signal at an arbitrary moment within the stop command holding time t, and supplies an ON / OFF control signal to each control terminal of the buffer 12a and the buffer 12b. Then, the buffer 12a switches to the enabled state, and the buffer 12b switches to the disabled state. Therefore, when the stop command holding time t is reached (step 104), the motor control unit 40a generates a stop command release signal at that moment, and gives an ON control signal to the control terminal of the inverter 11. Then, the inverter 11 is switched to the enable state, the supply of the high-frequency voltage from the oscillation drive circuit 10 to the piezoelectric body 22 is restarted, and the moving body 24 reverses clockwise (step 105).
[0049]
The positioning operation described above is also shown in the time chart of FIG. That is, in FIG. 4, the waveform (A) at the top represents the result of the determination by the motor control unit 40a as to whether or not the current position of the moving body 24 matches the target position. B) shows the result of the motor control unit 40a determining whether or not the current position of the moving body 24 is over the target position. Similarly, the third waveform from the top (C) represents the ON or OFF control signal given to the inverter 11 by the motor control unit 40a, and the fourth waveform (D) from the top represents the buffer from the motor control unit 40a. An ON or OFF control signal applied to the buffer 12b is shown in the lowermost waveform (E) of the motor control section 40a.
[0050]
The time chart in FIG. 4 shows that the motor control unit 40a performs a reverse rotation from the clockwise direction to the counterclockwise direction from the moment when the first match is detected, and after a stop command holding time of t1 time interval, and then the motor control unit 40a This indicates that the reverse rotation from the counterclockwise direction to the clockwise direction is performed after a stop command holding time of a time interval t2 from the moment when the second match is detected. Then, the stop command is issued at the moment when the motor control unit 40a detects the third match, but the position signal is still issued even if the predetermined stop command holding time is exceeded. Accordingly, FIG. 4 shows that the ultrasonic motor device 1 is in a settling state from the moment when the third match is detected.
[0051]
As shown in FIG. 4, the stop command holding time is set to a plurality of times, for example, t1 and t2. The time interval of t2 is set shorter than the time interval of t1. This focuses on the fact that the second overshoot is smaller than the first overshoot. The stop command holding time is a time interval from a time when the control unit detects that the moving body has reached the target position and issues a stop command to a time when a stop release command, that is, a start command is issued. The time interval until the stop of the motor 24 or the time interval until the vibration of the vibrating body 23 stops is set to be substantially the same. In view of this, the time interval of t2 is set shorter than t1.
[0052]
As is clear from FIG. 4, the stop command holding time includes a plurality of stop command times with different time intervals. The smaller the moving amount of the moving body 24 to the target position, the shorter the time interval is set. The time interval of the stop command holding time is set shorter as the moving body speed immediately before the stop command is input is lower. If the oscillation drive circuit 10 constitutes a self-excited oscillation circuit, the stop command holding time is equal to or longer than the time interval from when the stop command is input from the motor control unit 40a to when the self-excited oscillation of the self-excited oscillation circuit stops. It is desirable to be set to.
[0053]
As described above, the stop command holding time is determined according to the situation of the positioning control, and the specific value is empirically determined in units of several ms to several hundreds of μs. The stop command holding time determined in this way is set in the motor control unit 40a in advance. For example, in the control device 40 including a CPU, a ROM, a RAM, and the like, the stop command holding time is stored in the RAM by an input unit.
[0054]
According to the positioning control of the moving body 24 in the ultrasonic motor device 1 described above, the overshoot is reduced, and the settling time is significantly reduced. This fact will be apparent from FIG. 5A and 5B are characteristic diagrams of the position control of the ultrasonic motor device 1. FIG. 5A shows a case where the stop command holding time is 10 ms, FIG. 5B shows a case where the stop command holding time is 1 ms, and FIG. The respective characteristic diagrams when there is no holding time are shown. In FIG. 5, the vertical axis indicates the position of the moving body 24 expressed by the number of pulses, and the horizontal axis indicates time (× 10 ms).
[0055]
The maximum overshoot amount by the positioning control was about 1800 pulses when the stop command holding time in (A) was 10 ms, and was about 1900 pulses when the stop command holding time in (B) was 1 ms. On the other hand, according to the positioning control of the ultrasonic motor for performing the forward / reverse rotation without providing the stop command holding time, that is, when the stop command holding time in (C) is zero, the number of pulses was about 2100 pulses. . The settling time by the positioning control in the ultrasonic motor device 1 is about 490 ms when the stop command holding time of (A) is 10 ms, and about 430 ms when the stop command holding time of (B) is 1 ms. Met. On the other hand, according to the positioning control of the ultrasonic motor for performing the forward / reverse rotation without providing the stop command holding time, when the stop command holding time of (C) is zero, it is about 610 m. As is clear from these comparisons, according to the positioning control, the maximum overshoot amount was small, and the settling time was significantly short. Since the settling time was significantly reduced, the positioning resolution was improved.
[0056]
Incidentally, in a general configuration in which the ultrasonic motor is controlled to rotate by performing the forward / reverse rotation without providing the stop command holding time, even if the stop command is issued as described above, the moving body is not moved due to residual vibration and inertia. Since the moving body keeps moving for an extremely short time, if the moving body is immediately reversed every time it overshoots, the phenomenon that the moving body slips or the residual vibration at the time of normal rotation and the driving vibration of the reverse rotation overlap and the moving body Phenomenon is seen in which the frictional force between the vibration member and the vibrator is greatly reduced. On the other hand, the stop command holding time is provided as described above, and the moving body is reversed after the above-mentioned phenomenon disappears, so that the positioning performance is significantly improved as described above. it can.
[0057]
Meanwhile, in the positioning control in the ultrasonic motor device 1, as shown in FIG. 3, the actual settling time required from the start of the positioning until the overshoot converges to the settling state (T1, T2 in FIG. 5). , T3) have exceeded the predetermined settling time T, and the forced rotation control unit 40b of the control device 40 determines whether or not the settling time T has exceeded (step 106). If the actual settling time is equal to or shorter than the specified settling time T, step 106 determines that the positioning is successful, and the control device 40 positions and holds the moving body 24 of the ultrasonic motor device 1 at a predetermined target position and stops.
[0058]
If the actual settling time exceeds the specified settling time T, step 106 determines that the positioning has failed. Then, the forced rotation condition is satisfied, and the control device 40 causes the next step 107, that is, the forced rotation to be executed at an appropriate time, and forcibly continuously rotates the moving body 24 by one or more rotations. To stop. The forced rotation is performed by exciting the vibrating body 23 via the motor control unit 40a. In this case, the moving body 24 is rotated clockwise or counterclockwise, or these rotations are alternately repeated one or more times. It is forcibly rotated in such a rotation form.
[0059]
The positioning failure of the moving body 24 is caused by the fact that the contact portion between the friction material 24a and the projection 26 forming the pressure contact surface of the moving body 24 with which the projection 26 inclined with the excitation comes in contact is more worn than other parts of the friction material 24a. Is likely to occur when the situation has advanced.
[0060]
However, as described above, when it is determined that the positioning has failed, the moving body 24 is forcibly rotated. Therefore, the wear of the entire annular region of the friction material 24 a in contact with the protrusion 26 of the vibrating body 23 is promoted by the protrusion 26. Thus, the entire annular region is leveled. That is, at the time of the positioning failure, the friction material 24a, which is the pressure contact surface, is placed on the positioning area where the wear has progressed from the other (this is the area in contact with the projection 26 of the vibration body 23 including the target position on the moving body 24). ), And there are areas deviating therefrom and having a degree of wear smaller than the positioning area. In this state, the protrusion 26 promotes abrasion, so that the surface condition of the positioning region and other regions can be changed substantially uniformly. In addition, regardless of the wear caused by the forced rotation, the pressure contact state of the friction material 24a with the projection 26 is maintained by the pressing force of the spring 27.
[0061]
In the first embodiment, each time the positioning of the moving body 24 whose positioning is controlled to the target position as described above fails, the surface state of the friction material 24a partially roughened by the positioning operation up to that point is changed to the moving body 24. Can be restored by forced rotation.
[0062]
For this reason, the locally rough surface state of the friction material 24a further progresses, and the performance of converting the vibration of the vibrating body 23 into the rotation of the moving body 24 is reduced, that is, the motor efficiency can be suppressed from being reduced. . For the same reason, a specified settling time can be maintained, so that a decrease in the positioning accuracy of the moving body 24 can be suppressed.
[0063]
As described above, although it is inevitable that the surface of the friction material 24a becomes rough due to the positioning control, the surface state of the friction material 24a can be substantially uniformly recovered, so that the durability of the ultrasonic motor device 1 can be improved. Therefore, in the various electronic devices 3 on which the ultrasonic motor device 1 is mounted, it is possible to suppress a malfunction due to a reduction in the life of the ultrasonic motor device 1 and to reduce the life of the ultrasonic motor device 1 due to the wear. It is also possible to reduce the possibility that the need to replace the ultrasonic motor device 1 is generated.
[0064]
Next, second to seventh embodiments of the present invention will be described. Since these embodiments are basically the same as the first embodiment, the same components are denoted by the same reference numerals as those in the first embodiment, and description thereof will be omitted. Hereinafter, a configuration different from that of the first embodiment will be described. In this description, FIGS. 1 to 6 are referred to as needed.
[0065]
In the second embodiment shown in FIG. 7, the setting is made such that the forced rotation condition is satisfied when the time actually required for the positioning of the moving body 24 exceeds a predetermined positioning time. Here, the predetermined positioning time is a time obtained by adding a fixed fluctuation rate to the specified time to the specified time. At least one of a minus time or a plus time with respect to a specified time can be used as the fluctuation rate, and in the second embodiment, it is ± t% of the specified time. The value of t can be, for example, ± 10%, but is not limited thereto, and the plus time and the minus time do not have to be the same value.
[0066]
As a result, the reference value for determining the timing of whether the forced rotation condition is satisfied or not is set as an upper limit value obtained by adding a positive change rate to a specified value and a lower limit value obtained by adding a negative change rate to the specified value. You. After the forced rotation condition is satisfied, the moving body 24 is forcibly rotated immediately or immediately before the power is turned off or immediately after the next power is turned on.
[0067]
Step 108 of determining whether the forced rotation condition is satisfied is executed by the control device 40 after determining that the positioning is successful. In this case, the specified settling time T in step 106 is set longer than the upper limit. After determining in step 108 that the time actually required for positioning of the moving body 24 has exceeded the upper limit or not determining that the lower limit has not been reached, the control device 40 determines in step 106 that the positioning has failed. Is satisfied, the forced rotation condition in step 107 is satisfied.
[0068]
Depending on the surface condition of the positioning region of the friction material 24a, the motion conversion between the moving body 24 and the projection 26 becomes poor, and the moving body 24 is hardly moved substantially, making it difficult to converge the overshoot. Conceivable. In such a case as well, the upper limit is set as the criterion in step 108, so that the rotation can be shifted to the forced rotation as appropriate. Conversely, depending on the surface condition of the positioning region of the friction material 24a, the efficiency of the ultrasonic motor device 1 decreases, and as the number of rotations decreases, the overshoot decreases and the time actually required for positioning decreases. It may be shorter. In such a case as well, the lower limit is set as a criterion in step 108, so that it is possible to timely shift to forced rotation.
[0069]
If it is determined in step 108 that the time actually required for positioning the moving body 24 is included between the upper limit value and the lower limit value, the control device 40 sets the moving body 24 of the ultrasonic motor device 1 to a predetermined position. And stop.
[0070]
Except for the matters described above, the third embodiment is the same as the first embodiment. Therefore, also in the second embodiment, it is possible to obtain the same operation as in the first embodiment to solve the problem of the present invention. In addition, in the second embodiment, after each of the determination results in steps 106 and 108 is NO, the process shifts to the forced rotation, and the settling time specified for the execution of step 106 is set. Even in T, the forced rotation may be performed by the execution of step 108, so that the entire friction material 24a forming the pressure contact surface of the moving body 24 is leveled and the surface state of the pressure contact surface is maintained substantially uniform. It is superior to the first embodiment in that it is easy to perform. However, step 106 can be omitted in the second embodiment.
[0071]
In the third embodiment shown in FIG. 8, the setting is made such that the forced rotation condition is satisfied when the positioning of the moving body 24 exceeds the preset number N of times of positioning. Here, the execution of the positioning refers to a series of operations for converging the overshoot to the target position, not the number of overshoots, and the number N can be set arbitrarily, for example, 100 times. After the forcible rotation condition is satisfied, the mobile unit 24 is forcibly rotated at an appropriate time, such as immediately before power-off or immediately after the next power-on. The rotation speed N can be set, for example, according to the surface condition of the friction material 24a. In this case, an optimal numerical value is selected based on the sampling data.
[0072]
That is, step 109 for determining whether or not the forced rotation condition is satisfied is executed by the control device 40 after the positioning is completed within the specified time in step 106 and the positioning is determined to be successful. After it is determined in this step 109 that the actual positioning of the moving body 24 exceeds the preset number of times of performing the positioning (NO), the step is performed in the same manner as in the case where it is determined that the positioning has failed in the step 106. The forced rotation of 107 is performed by the control device 40. If the determination in step 109 is YES, the control device 40 positions and holds the moving body 24 of the ultrasonic motor device 1 at a predetermined target position and stops the moving body 24.
[0073]
Except for the matters described above, the third embodiment is the same as the first embodiment. Therefore, also in the third embodiment, it is possible to obtain the same operation as in the first embodiment, and to solve the problem of the present invention. In addition, in the third embodiment, after each of the determination results of steps 106 and 109 becomes NO, the rotation is shifted to the forced rotation, so that the entire friction material 24a forming the pressure contact surface of the moving body 24 is evenly distributed. This is superior to the first embodiment in that the surface state of the pressure contact surface is easily maintained substantially uniform.
[0074]
In the fourth embodiment shown in FIG. 9, the setting is made such that the forced rotation condition is satisfied immediately after the predetermined power is turned on. Here, the term “immediately after turning on the power” may be immediately after turning on the power every time. However, in the fourth embodiment, it is assumed that the number of times of turning on the power has reached a predetermined number. After the forced rotation condition is satisfied, the moving body 24 is forcibly rotated immediately or immediately before the power is turned off or immediately after the next power is turned on.
[0075]
That is, step 111 of determining whether or not the forced rotation condition is satisfied is executed by the control device 40 after the power is turned on (step 110) to the electronic device 3 on which the ultrasonic motor device 1 is mounted. If the number of power-on times does not reach the predetermined integration number, the determination in step 111 is NO, so the process proceeds to the next step 112, where the system of the electronic device 3 is in a start-up preparation state. After a predetermined time, the system of the electronic device 3 is operated (step 113). When the number of power-on times has reached the predetermined number of times of integration, the determination in step 111 is YES, and control device 40 executes forced rotation in step 107. Then, after the execution of the forced rotation is completed, the process proceeds to step 112 in which the system of the electronic device 3 is set to the startup preparation state, and step 113 is further executed after a predetermined time to operate the system of the electronic device 3. .
[0076]
Except for the matters described above, the third embodiment is the same as the first embodiment. Therefore, in the fourth embodiment as well, it is possible to obtain the same operation as in the first embodiment to solve the problem of the present invention. Moreover, the fourth embodiment in which the forced rotation is performed immediately after the power is turned on as described above is preferable in that the unnaturalness in the operation of the ultrasonic motor device 1 can be apparently suppressed.
[0077]
In the fifth embodiment shown in FIG. 10, the setting is made such that the forced rotation condition is satisfied immediately before the power supply of the system of the electronic device 3 is cut off. The term “immediately before power-off” may be immediately before each power-off, but in the fifth embodiment, immediately before power-off reaches a predetermined number. After the forced rotation condition is satisfied, the movable body 24 is forcibly rotated immediately or at an appropriate time such as immediately after the next power-on.
[0078]
That is, in step 111 for determining whether or not the forced rotation condition is satisfied, it is determined in step 116 whether the system power switch is turned off during the operation of the electronic device 3 equipped with the ultrasonic motor device 1 (step 115). The determination is YES, and the control device 40 executes the process after the system of the electronic device 3 is terminated (step 117). In this case, the electronic device 3 has a battery (auxiliary power supply) (not shown) that is used based on a signal when the power switch is turned off, and can execute Step 111 and the like with the power of the auxiliary power supply.
[0079]
If the number of power cutoffs does not reach the predetermined number of integrations, the determination in step 111 is NO, so the control device 40 executes the next step 118 to cut off the power supply from the auxiliary battery and 3. Shut down all systems. If the number of power cutoffs reaches the predetermined number of integrations, the determination in step 111 becomes YES at that point, and thus the control device 40 executes the forced rotation in step 107. Then, after the execution of the forced rotation, the control device 40 executes step 118 to stop the entire system of the electronic device 3.
[0080]
Except for the matters described above, the third embodiment is the same as the first embodiment. Therefore, also in the fifth embodiment, the same effects as those of the first embodiment can be obtained to solve the problem of the present invention. Moreover, the fifth embodiment in which the forced rotation is performed immediately before the power is turned off as described above is preferable in that the unnaturalness in the operation of the ultrasonic motor device 1 can be apparently suppressed. As the number of power-on times in the fourth embodiment and the number of power-off times in the fifth embodiment, for example, by taking sampling data in advance, an optimum number can be selected based on the result.
[0081]
In the sixth embodiment shown in FIG. 11, when the number of overshoots at the time of positioning exceeds a predetermined number of times, or the amount of deviation of the overshoot at the time of positioning from the target position is set in advance. Is set so that the forced rotation condition is satisfied when the specified value is exceeded. Here, the number of overshoots refers to the number of overshoots in a series of operations for converging the overshoot to the target position, in other words, the number of times of correcting the overshoots, for example, as shown in FIGS. 5A and 5B. In each case, it is three times. The shift amount is defined by the peak of the overshoot with respect to the target position. For example, in FIGS. 5A and 5B, the maximum shift amount can be indicated by reference characters X and Y. These prescribed times and prescribed values can be set arbitrarily. After the forced rotation condition is satisfied, the moving body 24 is forcibly rotated immediately or immediately before the power is turned off or immediately after the next power is turned on.
[0082]
That is, when the positioning of the moving body 24 is started (step 121), in the next step 122 in which it is determined whether or not the forced rotation condition is satisfied during the positioning operation, the overshoot occurring in the positioning is counted and the number of times is determined. Is determined whether or not exceeds a predetermined number of times. If the number of overshoots exceeds the specified number, the determination in step 122 is NO. Therefore, at an appropriate time thereafter, the control device 40 executes the forced rotation in step 107.
[0083]
On the other hand, when it is determined in step 122 that the forced rotation condition is not satisfied (determination is YES), the control device 40 monitors in step 101 whether the current position of the moving body 24 is the target position. If it is detected by this monitoring that the current position of the moving body 24 has not reached the target position (YES), the control device 40 executes step 102, generates a stop command signal, and gives it to the oscillation drive circuit 10. Subsequently, the control device 40 checks whether or not there is an overshoot (step 103). If it is determined that there is no overshoot (NO), the positioning ends.
[0084]
If it is determined in step 103 that there is an overshoot (YES), control device 40 executes next step 123 to determine whether or not the amount of overshoot deviation exceeds a predetermined value. I do. If the deviation exceeds the specified value, the determination in step 123 becomes NO, and thereafter, at an appropriate time thereafter, the control device 40 executes the forced rotation in step 107. If the deviation does not exceed the specified value, the determination in step 123 is YES, so the control device 40 supplies a reverse rotation command signal to the oscillation drive circuit 10 to perform a reverse rotation operation (step 105). ). In this case, a predetermined time has elapsed since the generation of the stop command signal. After step 105, the process returns to step 122 and repeats the above-described operation. If it is determined in step 103 that there is no overshoot, the positioning correction operation ends, and the control device 40 The moving body 24 of the acoustic wave motor device 1 is positioned and stopped at a predetermined target position.
[0085]
Except for the matters described above, the third embodiment is the same as the first embodiment. Therefore, also in the sixth embodiment, the same effects as those of the first embodiment can be obtained, and the problem of the present invention can be solved. Depending on the surface condition of the positioning region of the friction material 24a, the motion conversion between the moving body 24 and the projection 26 becomes poor, and the moving body 24 is hardly moved substantially, making it difficult to converge the overshoot. Conceivable. In such a case, it is superior to the first embodiment in that it is possible to timely shift to the forced rotation based on the determination in step 122. Further, a change in the surface state of the friction plate 24a due to the repetition of the positioning of the moving body 24 may increase the amount of shift of the overshoot with respect to the target position. In this case, the settling time also becomes longer. In this case, the second embodiment is superior to the first embodiment in that it can timely shift to the forced rotation based on the determination in step 123. It goes without saying that the prescribed number of overshoots and the prescribed value of the amount of deviation can be set to optimal values based on sampling data taken in advance.
[0086]
In the seventh embodiment shown in FIG. 12, the structure adopted in the first embodiment to reduce the overshoot and shorten the settling time, that is, the moving body 24 is set at a stop command holding time from the moment of the overshoot. The steps for reversing the configuration are omitted.
[0087]
Therefore, when the positioning of the moving body 24 is started (step 121), in the next step 101, it is monitored whether or not the current position of the moving body 24 is the target position. Accordingly, when it is detected that the current position of the moving body 24 has reached the target position, the control device 40 executes the next step 103 to check whether or not there is an overshoot. If it is determined in step 103 that there is no overshoot, the positioning correction operation ends, and the control device 40 positions and holds the moving body 24 of the ultrasonic motor device 1 at a predetermined target position and stops it. If it is determined in step 103 that there is an overshoot, the control device 40 executes the next step 105 to immediately reverse the moving body 24, and after this step 105, returns to step 101 and returns to step 101. The above operation is repeated.
[0088]
Apart from this settling operation, in the seventh embodiment, as in the first embodiment, when the actual settling time exceeds the specified settling time, step 106 is determined to be a positioning failure, and thereafter, executed at an appropriate time And step 107 for forcibly rotating the moving body 24 one or more times continuously. Therefore, when the forced rotation condition is satisfied, the moving body 24 can be forcibly rotated.
[0089]
Except for the matters described above, the third embodiment is the same as the first embodiment. Therefore, also in the seventh embodiment, the same effects as those of the first embodiment can be obtained to solve the problem of the present invention.
[0090]
In the eighth embodiment shown in FIGS. 13 and 14, when the forced rotation condition is satisfied, the target position for positioning is set by the target position changing unit 40c of the control device 40 (this is provided instead of the forced rotation control unit). It is changed and used. In this case, the forced rotation condition may be any of the conditions described in the first to seventh embodiments.
[0091]
An image in which the moving body 24 is rotated by a predetermined angle will be described with reference to FIG. FIG. 14 is a view of the moving body 24 as viewed from the friction material 24a side. In FIG. 14, reference symbol D indicates, for example, a target position set when positioning the moving body 24. Arrows E and F pointing left and right around the target position indicate the locus of overshoot of the moving body 24 with respect to the projection 26. A region which is shown as a representative and which is drawn with a reference numeral D as a center and which is indicated by parallel oblique lines indicates a positioning region G. The positioning region G is formed at and near the target position D, that is, a portion that is worn by contact with the projection 26 due to overshoot. The portions deviating from these positioning regions G are sound regions H, and the degree of wear of the regions H is smaller than that of the positioning regions G.
[0092]
The wear of the positioning area G progresses according to the operation of the ultrasonic motor device 1. However, when it is determined that the forced rotation condition is satisfied, the target position changing unit 40c of the control device 40 determines the target position for positioning the moving body 24. D is changed so as to be shifted in the circumferential direction by 90 °, for example, as shown by a two-dot chain line in FIG. 14 so that the positioning area G is positioned in the previous healthy area H. In addition, with the change of the used position for this positioning, various automatic adjustments are performed in order to achieve consistency with the change, and a program for such adjustment is stored in advance in the ROM of the control device 40 or the like. Have been.
[0093]
With the above change, the moving body 24 can be positioned using the region H in a healthy state where the wear has not progressed as compared with the previous positioning region. Therefore, despite the fact that the entire pressure contact surface of the moving body 24 in frictional contact with the vibrating body 23 is not leveled and the forced rotation for maintaining the surface state of the pressure contact surface substantially uniform is not performed, The durability of the motor device 1 can be improved.
[0094]
The present invention is not limited to the standing wave type ultrasonic motor, but can be applied to a traveling wave type ultrasonic motor or the like. Further, the oscillation driving circuit 10 is not limited to the one using the self-excited oscillation circuit, but may be one using a separately excited oscillation circuit.
[0095]
【The invention's effect】
According to the present invention, regardless of the positioning of the moving body, every time the forced rotation of the moving body that is in frictional contact with the vibrating body is performed, the entire pressure contact surface of the moving body is leveled, Since the surface state of the contact surface can be maintained substantially uniform, it is possible to provide an ultrasonic motor device having excellent durability and an electronic device including the device.
[0096]
According to the present invention, regardless of the positioning of the moving body, each time the forced rotation condition of the moving body that is in frictional contact with the vibrating body is satisfied, the area that has deviated from the positioning area on the moving body so far and has less wear Is used as a new positioning region, so that it is possible to provide an ultrasonic motor device having excellent durability and an electronic apparatus including the device.
[Brief description of the drawings]
FIG. 1 is a sectional view showing a configuration of an ultrasonic motor device according to a first embodiment of the present invention.
FIG. 2 is a block diagram showing the configuration of the ultrasonic motor device shown in FIG.
FIG. 3 is a flowchart illustrating a positioning operation and a forced rotation operation of the ultrasonic motor device of FIG. 1;
FIG. 4 is a time chart for explaining the operation of the ultrasonic motor device shown in FIG. 1;
5A and 5B are characteristic diagrams showing a relationship between an overshoot at the time of positioning of the ultrasonic motor device of FIG. 1 and a settling time. (C) is a characteristic diagram showing the relationship between the overshoot and the settling time during positioning of the conventional ultrasonic motor device.
FIG. 6 is a block diagram showing a configuration of an electronic apparatus of the present invention on which the ultrasonic motor device of FIG. 1 is mounted.
FIG. 7 is a flowchart illustrating a positioning operation and a forced rotation operation of the ultrasonic motor device according to the second embodiment of the present invention.
FIG. 8 is a flowchart illustrating a positioning operation and a forced rotation operation of the ultrasonic motor device according to the third embodiment of the present invention.
FIG. 9 is a flowchart illustrating a forced rotation operation of an ultrasonic motor device according to a fourth embodiment of the present invention.
FIG. 10 is a flowchart illustrating a forced rotation operation of an ultrasonic motor device according to a fifth embodiment of the present invention.
FIG. 11 is a flowchart illustrating a forced rotation operation of an ultrasonic motor device according to a sixth embodiment of the present invention.
FIG. 12 is a flowchart illustrating a positioning operation and a forced rotation operation of an ultrasonic motor device according to a seventh embodiment of the present invention.
FIG. 13 is a block diagram showing a configuration of an ultrasonic motor device according to an eighth embodiment of the present invention.
FIG. 14 is a view for explaining an image of a change of a target position in the ultrasonic motor device according to the eighth embodiment.
[Explanation of symbols]
1. Ultrasonic motor device
2. Ultrasonic motor
3. Electronic equipment
4 ... Transmission mechanism
5. Output mechanism
10. Oscillation drive circuit
21a: Clockwise rotation electrode
21b: Electrode for counterclockwise rotation
21c ... common electrode
22: Piezoelectric body
23 ... vibrator
24 ... moving object
24a: friction material
25 ... Spring (pressurizing means)
26 ... projection
30 ... Position sensor
40 ... Control device
40a: motor control unit
40b ... forced rotation control
40c: target position changing unit

Claims (13)

A vibrating body having a piezoelectric body;
A moving body arranged to rotate in a clockwise or counterclockwise direction by the vibration of the vibrating body in frictional contact with the vibrating body;
A pressure mechanism for bringing the moving body into pressure contact with the vibrating body;
An electrode for applying a high-frequency voltage to the piezoelectric body,
An oscillation drive circuit that generates the high-frequency voltage;
A position sensor that generates a position signal of the moving body,
A command signal is given to the oscillation drive circuit to control the application of a high-frequency voltage to the piezoelectric body to start and stop the moving body, to perform normal rotation and reverse rotation, and to input a target position and the position signal. And a motor control unit that performs positioning so that the position of the moving body becomes the target position, and determines whether or not a previously input forced rotation condition has been satisfied, and the forced rotation condition has been satisfied. A control device having a forced rotation control unit for forcibly continuously rotating the moving body one or more rotations later;
An ultrasonic motor device comprising: A vibrating body having a piezoelectric body;
A moving body arranged to rotate in a clockwise or counterclockwise direction by the vibration of the vibrating body in frictional contact with the vibrating body;
A pressure mechanism for bringing the moving body into pressure contact with the vibrating body;
An electrode for applying a high-frequency voltage to the piezoelectric body,
An oscillation drive circuit that generates the high-frequency voltage;
A position sensor that generates a position signal of the moving body,
A command signal is given to the oscillation drive circuit to control the application of a high-frequency voltage to the piezoelectric body to start and stop the moving body, to perform normal rotation and reverse rotation, and to input a target position and the position signal. And a motor control unit that performs positioning so that the position of the moving body becomes the target position, and determines whether or not a previously input forced rotation condition has been satisfied, and the forced rotation condition has been satisfied. Later, a target position change that changes the target position so that a region deviating from the positioning region including the target position on the moving body and in contact with the vibrating body and having smaller wear than the positioning region is the positioning region. A control device having a unit;
An ultrasonic motor device comprising: The ultrasonic motor device according to claim 1 or 2, wherein the forced rotation condition is satisfied when a time required for the positioning exceeds a preset settling time. 3. The super-rotating condition according to claim 1 or 2, wherein the forced rotation condition is satisfied when a predetermined positioning time that is set in advance is taken into account in consideration of a specified time and a constant variation rate with respect to the specified time. Sound wave motor device. The ultrasonic motor device according to claim 1, wherein the forced rotation condition is satisfied when the positioning is performed for a predetermined number of times. 3. The ultrasonic motor device according to claim 1, wherein the forced rotation condition is satisfied immediately after power-on. The ultrasonic motor device according to claim 1 or 2, wherein the forced rotation condition is satisfied immediately before power-off. The ultrasonic motor device according to claim 1 or 2, wherein the forced rotation condition is satisfied when the number of overshoots at the time of positioning exceeds a predetermined number of times set in advance. The ultrasonic wave according to claim 1 or 2, wherein the forced rotation condition is satisfied when an amount of deviation of the overshoot from the target position during the positioning exceeds a predetermined value. Motor device. The ultrasonic motor device according to any one of claims 1 to 9, wherein the forcible rotation is performed by rotating the moving body clockwise. The ultrasonic motor device according to any one of claims 1 to 9, wherein the forcible rotation is performed by rotating the moving body in a counterclockwise direction. The ultrasonic motor device according to any one of claims 1, 3 to 9, wherein the forcible rotation is performed by rotating the moving body at least once in a clockwise direction and a counterclockwise direction. An electronic apparatus comprising: the ultrasonic motor device according to any one of claims 1 to 12; and an output mechanism linked to a moving body of the motor device.

Images