JPH07222466A - Controller of ultrasonic motor - Google Patents

Abstract

PURPOSE:To facilitate a smooth operation at the time of intermittent driving and save a power consumption by a method wherein the moved distance of one movement of a moving unit in the case of an intermittent driving is so controlled as to be a maximum moved distance up to which the moving unit can be moved smoothly in relation to a moving speed. CONSTITUTION:A target speed setting means 8 outputs the target speed of a moving unit 26 to a speed control means 9. The speed control means 9 conducts an arithmetic process and controls the frequency of a frequency signal so as to have the moving speed of the moving unit 26 equal to the target speed. Further, in the case of intermittent driving, the moved distance of one time is set at a maximum moved distance up to which the moving unit 26 can be moved smoothly in relation to the moving speed of the moving unit 26 and a frequency signal whose phase is different from the previous one by 90 deg. is outputted. Those frequency signals are amplified to certain voltage levels by power amplifying means 10 and 11 and applied to an ultrasonic motor 1 to make a vibrator 23 vibrate and the moving unit 26 is driven. A driving frequency control means 6 controls the driving frequency in accordance with an information from a position information detecting means 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic motor control device for generating a driving force by exciting elastic waves in a vibrating body using a piezoelectric body such as piezoelectric ceramics.

[0002]

2. Description of the Related Art In recent years, attention has been paid to ultrasonic motors which use elastic waves as a driving force by exciting elastic waves in a vibrating body using a piezoelectric body such as piezoelectric ceramics.

A conventional technique of an ultrasonic motor and its driving method will be described below with reference to the drawings.

FIG. 8 is a partially cutaway perspective view of a ring-shaped ultrasonic motor. A ring-shaped piezoelectric ceramic 22 (hereinafter referred to as a piezoelectric body) as a piezoelectric body is attached to one of the ring-shaped surfaces of a ring-shaped elastic body 21. The vibrating body 23 is also formed. Further, the moving body 26 is formed by bonding the annular elastic body 25 and the friction material 24 made of a wear resistant material. This moving body 26 is a friction material 24.
It is in pressure contact with the vibrating body 23 via.

Drive electrodes (not shown) provided on the piezoelectric body 22
When an AC voltage is applied to the vibrating body 23, a progressive wave of flexural vibration having a radial displacement as shown in FIG. Due to the lateral component of the wave front of this traveling wave, the moving body 26 is frictionally driven and rotates.

FIG. 10 is an explanatory diagram showing the operating principle of the ultrasonic motor in which the moving body 26 is frictionally driven by the traveling wave of the flexural vibration excited by the vibrating body 23. The arbitrary point A on the surface of the vibrating body 23 is excited by the traveling wave of the flexural vibration,
It makes an elliptic motion of the minor axis 2u. The moving body 26, which is installed on the vibrating body 23 under pressure, moves in the direction opposite to the traveling direction of the traveling wave due to the frictional force of the contact surface by contacting the vibrating body near the apex of the elliptical locus. The vibration amount of the vibrating body 23 is the piezoelectric body 22.
The lateral component u of the wave front of the traveling wave is determined by the amount of vibration of the vibrating body 23. Mobile 26
Of the traveling wave is determined by the product of the lateral component u of the wave front of the traveling wave and the angular frequency ω of the flexural vibration as shown in (Equation 1),

[0007]

## EQU1 ## The output torque at this time is determined by the frictional force between the vibrating body 23 and the moving body 26.

In the ultrasonic motor, two sets of drive electrodes are arranged on the piezoelectric body 22 so as to be displaced by a predetermined position, drive terminals are taken out, and AC voltages having different predetermined phases are applied to the two drive terminals, respectively. As a result, the standing wave of two flexural vibrations displaced in position can be excited in the vibrating body 23, and as a result, the traveling wave of the flexural vibration can be excited. At this time, 2
If the amplitudes of the two standing waves are equal, a traveling wave with a small standing wave component can be obtained, and the moving body 26 can be driven more efficiently than the operating principle. The vibrating body 23 exhibits resonance / anti-resonance characteristics when viewed from the drive terminal, as in the case of the piezoelectric body 22 alone. Therefore, if it is driven in the vicinity of the resonance frequency, it can be efficiently driven at a low voltage.

As described above, since the ultrasonic motor uses the traveling wave of bending vibration, the moving speed of the moving body 26 and the vibration amount of the vibrating body 23 are in a proportional relationship. Therefore, in order to reduce the speed of the moving body 26, the driving voltage may be reduced to reduce the vibration amount of the vibrating body 23 and the lateral component u may be reduced. However, if the vibration amount becomes too small, the contact surface of the vibrating body 23 or the moving body 26 may be uneven,
The apex of the ellipse cannot stably contact the contact surface of the moving body 26, and the speed of the moving body 26 becomes unstable. FIG. 11 shows a characteristic diagram of the relationship between the vibration amount and the moving speed. From FIG. 11, when the moving body 26 is moved at a speed lower than the moving speed v,
Figure intermittently driving voltage in every cycle T ₁ as shown in 12 (a) by applying only the period T _2, it is in the low speed purposes the average speed of the moving object (c).

Items required for intermittent driving of the ultrasonic motor include smooth operation, reduction of power consumption, prevention of sound and vibration, and the like. In order to perform a smooth motion, it is necessary to set the amount of movement once to be within the range of smooth movement. The maximum movement amount of the smoothly moving movement range changes according to the movement speed, and the lower the speed becomes, the smaller the maximum movement amount becomes. FIG. 13 is a characteristic diagram showing the relationship between the maximum moving amount s that moves smoothly with respect to the moving speed v.

In order to reduce the power consumption, it is necessary to reduce the number of times of starting and stopping because the loss at the time of starting and stopping is large. Further, since the cause of the sound and vibration is mainly due to the abrupt change of the moving speed, it is necessary to make the abrupt change of the moving speed gentle in order to prevent the occurrence of the sound and the vibration.

In order to perform a smooth operation, the conventional ultrasonic motor control device responds to such requirements by
The amount of movement per turn is set within the range of smooth movement. Specifically, as shown in the characteristic diagram of FIG. 13, the lower the moving speed v is, the smaller the maximum moving amount s is. Therefore, one moving amount should be within the moving range that moves smoothly even at low speed. The drive cycle is set to short.

In order to prevent the generation of sound and vibration,
A drive voltage is controlled by a microcomputer (hereinafter referred to as a microcomputer). Specifically, in order to smooth out a sudden change in the moving speed, the microcomputer is controlled so that the voltage is gradually increased at startup and gradually decreased at stop.

[0014]

However, in the conventional ultrasonic motor control device, the drive cycle is set to be short in order to perform a smooth operation, and therefore, the start and stop are repeated more than necessary at the high speed. There was a problem of increasing the loss at the stop. Also, because the drive voltage is controlled by the microcomputer to prevent the generation of noise and vibration,
Since the processing load on the microcomputer is increased and the voltage can be controlled only discretely, the change in the moving speed is also discrete.
There is a problem that it is impossible to prevent the generation of sound and vibration.

The present invention solves the above-mentioned conventional problems. In the invention described in claim 1, the moving amount of the moving body is always smooth one time according to the moving speed during intermittent driving of the ultrasonic motor. An ultrasonic motor that reduces the power loss by starting and stopping by minimizing the number of times of starting and stopping as well as smoothing the operation by controlling to the maximum moving amount. It is an object of the present invention to provide a control device of.

According to a second aspect of the present invention, when the ultrasonic motor is intermittently driven, a voltage change due to charging / discharging of a capacitor of the step-up means is used, and the changed drive voltage is applied to the ultrasonic motor to thereby move the moving speed. It is an object of the present invention to provide a control device for an ultrasonic motor that smoothes the changes in the above, prevents the generation of sound and vibration, and reduces the processing load of the microcomputer.

[0017]

In order to achieve this object, a control device for an ultrasonic motor according to a first aspect of the present invention comprises a speed information detecting means for detecting information on a moving speed of a moving body, and a moving position of the moving body. Based on the output information of the position information detecting means for detecting the information regarding the position information, the target speed setting means for setting the target speed of the moving body, and the speed information detecting means so that the moving speed of the moving body becomes the target speed. A frequency control means for controlling the frequency of the frequency voltage to set the moving amount of the moving body once to the maximum moving amount for smooth movement in accordance with the moving speed of the moving body during intermittent driving; Drive cycle control means for controlling the drive cycle based on the output information of the position information detection means so that the amount of movement of the moving body at a time becomes the set value of the speed control means.

The ultrasonic motor control apparatus according to a second aspect of the present invention includes speed information detecting means for detecting information on a moving speed of a moving body, target speed setting means for setting a target speed of the moving body, The frequency of the frequency voltage is controlled so that the moving speed of the moving body becomes the target speed on the basis of boosting means for boosting the power supply voltage for driving the sonic motor to a constant level and output information of the speed information detecting means. And speed control means for controlling ON / OFF of the boosting means at the time of starting and stopping.

[0019]

According to the invention as set forth in claim 1, the operation is smoothed by controlling the movement amount of the moving body at one time to be the maximum movement amount for smooth movement according to the movement speed at the time of intermittent driving. In addition, since it is possible to minimize the number of times of starting and stopping, it is possible to reduce loss during starting and stopping and reduce power consumption.

According to a second aspect of the present invention, the voltage boosting means is turned on when the ultrasonic motor is started, the voltage boosting means is turned off when the ultrasonic motor is stopped, and the voltage generated by charging and discharging the capacitor of the voltage boosting means is turned on and off. Take advantage of change,
By applying this changed drive voltage to the ultrasonic motor, the movement speed change is smoothed without controlling the drive voltage by the conventional microcomputer, and the sound and vibration are prevented from occurring and the processing of the microcomputer is performed. The burden can be reduced. Further, by turning off the boosting means at the time of stop, it is possible to reduce the loss in the boosting means and reduce the power consumption.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an ultrasonic motor controller according to the first embodiment of the present invention. In FIG. 1, reference numeral 1 is an ultrasonic motor composed of a vibrating body 23 and a moving body 26, and 2 is a velocity information of the moving body 26 by detecting a vibration amount of the vibrating body 23 as a speed information detecting means of the ultrasonic motor 1. And a vibration amount detecting means 3 for detecting the A / D for converting an analog signal output from the vibration amount detecting means 2 into a digital signal.
The conversion means 4, a position information detection means for detecting the position of the moving body 26, 5 an A / D conversion means for converting an analog signal output from the position information detection means 4 into a digital signal, and 6 are always 1 during intermittent driving. Drive cycle control means 7 for controlling the drive cycle based on the information from the position information detection means 4 so that the moving amount of the moving body 26 at one time becomes a value set by the speed control means 9.
Is information storage means for storing relationship data between the moving speed of the moving body 26 and the vibration amount of the vibrating body 23, 8 is a target speed setting means for setting a target speed of the moving body 26 and outputting a switching speed command value, and 9 is , The frequency of the frequency signal is controlled so that the moving speed of the moving body 26 becomes the target speed set by the target speed setting means 8, and the movement amount of one time is smoothed according to the moving speed of the moving body 26 during intermittent driving. The speed control means, 10 and 11, which set the maximum movement amount to move to and output frequency signals with different 90 ° phases,
The frequency signals output from the speed control means 9 and having different 90 ° phases are amplified or boosted to a voltage level required to drive the ultrasonic motor 1, and a constant voltage level is applied to each electrode of the piezoelectric body. Is a power amplifying means for applying a power.

The drive cycle control means 6 and the speed control means 9 are executed by the arithmetic processing by the microcomputer 16. FIG. 2 is a flowchart showing the process of the arithmetic processing of the speed control means 9, and FIG. 3 is the drive cycle. 6 is a flowchart showing a process of arithmetic processing of control means 6.

The operation of the control device for the ultrasonic motor of the first embodiment constructed as above will be described below with reference to the drawings.

The target speed setting means 8 outputs the target speed of the moving body 26 to the speed control means 9. The speed control means 9 performs arithmetic processing to control the frequency of the frequency signal so that the moving speed of the moving body 26 becomes the target speed, and smoothes the moving amount of one time according to the moving speed of the moving body 26 during intermittent driving. Set to the maximum amount of movement, and output frequency signals with 90 ° different phases.
When these frequency signals are amplified to a constant voltage level by the power amplifying means 10 and 11 and applied to the ultrasonic motor 1, the vibrating body 23 vibrates and the moving body 26 is driven. This vibrating body 23
The amount of vibration of the vibration amount detection means 2 as the speed information detection means
And output to the speed control means 9 through the A / D conversion means 3.

The speed control means 9 performs the arithmetic processing shown in FIG. 2 based on this vibration amount and the speed command value output from the target speed setting means 8. The processing will be described below in the order of the flowchart. .

In step S1, the target speed of the moving body 26 set by the target speed setting means 8 is read in step S2.
Proceed to. In step S2, the target vibration amount corresponding to the target speed of the moving body 26 is read from the information storage means 7 in step S2.
Go to 3. In step S3, it is checked whether the target speed of the moving body 26 has changed, and if it has changed, step S1
If there is no change, proceed to step S4. In step S4, the current vibration amount of the vibrating body 23 is read and the process proceeds to step S5.

In step S5, it is checked whether the driving is intermittent or not. When the driving is intermittent, the process proceeds to step S6, and when the driving is continuous, the process proceeds to step S7. In step S6, the current moving speed of the moving body 26 is estimated from the current vibration amount read in step S4, and the maximum moving amount that smoothly moves in one movement according to the moving speed is set in the drive cycle control means 6 S7
Proceed to.

In step S7, the difference between the target vibration amount read in step S2 and the current vibration amount read in step S4 is calculated, a speed error is calculated, and the process proceeds to step S8.
In step S8, it is estimated whether the current moving speed of the moving body 26 is slower than the target speed by comparing whether the speed error obtained in step S7 is greater than 0. If it is slow, the process proceeds to step S9, and if it is fast, the process proceeds to step S10. In step S9, arithmetic processing is performed, the drive frequency is lowered, and the process proceeds to step S3. In step S10, arithmetic processing is performed, the drive frequency is increased, and the process proceeds to step S3.

In this way, the moving speed of the moving body 26 is controlled to reach the target speed.

At the same time, the drive cycle control means 6 performs the arithmetic processing shown in FIG. 3 based on the amount of movement of the position of the moving body 26 detected by the position information detecting means 4 and the A / D converting means 5. However, the processing will be described below in the order of the flowchart.

In step 11, the one-time movement amount Xs set by the speed control means 9 is read and the process proceeds to step 12. In step S12, it is checked whether or not the movement amount Xs for one time has changed, and if it has changed, the process proceeds to step S11, and if it has not changed, the process proceeds to step S13. In step S13, the current position X0 of the moving body 26 detected by the position information detecting means 4 and the A / D converting means 5 is read in step S14.
Proceed to. In step S14, target position Xm = current position X0 +
The movement amount Xs is calculated once, and the process proceeds to step S15. In step S15, the timer is reset and the process proceeds to step S16.
In step S16, the ultrasonic motor is activated and the process proceeds to step S17.

In step S17, the current position Xn of the moving body 26 detected by the position information detecting means 4 and the A / D converting means 5 is read, and the process proceeds to step S18. Step S1
In step 8, whether or not the current position Xn has reached the target position Xm is checked. If the current position Xn has arrived, the process proceeds to step S19, and if not, the process proceeds to step S17.

In step S19, the ultrasonic motor is stopped and the process proceeds to step S20. At step S20, the current timer value T
n is read and the process proceeds to step S21. In step S21, the process waits until the current timer value reaches 2Tn, and when it reaches 2Tn, the process proceeds to step S12.

In the above description, the case where the start / stop time ratio is set to 1: 1 has been described, but the time ratio can be easily changed by changing the timer value in step S21.

Further, when reversing the moving direction, it is only necessary to change the formula for obtaining the target position Xm in step S14 to the target position Xm = the current position X0−1 times the moving amount Xs.

In this way, the moving amount of the moving body 26 is controlled so that it always reaches the set value.

As described above, according to the first embodiment, the operation is performed by controlling the movement amount of one time always to be the maximum movement amount that smoothly moves according to the movement speed of the moving body during intermittent driving. Can be smooth.

The second embodiment of the present invention will be described below with reference to the drawings.

FIG. 4 is a block diagram showing the configuration of an ultrasonic motor controller according to the second embodiment of the present invention. 4, blocks having the same components as those in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted. Here, 12 is a boosting means for boosting the power supply voltage for driving the ultrasonic motor 1 to a constant level, and 13 is a frequency signal so that the moving speed of the moving body 26 becomes the target speed set by the target speed setting means 8. The frequency of the booster means 12 is controlled at the time of starting and stopping,
Speed control means for performing OFF control and outputting frequency signals with different 90 ° phases, and 14 and 15 boosting the frequency signals with different 90 ° phases output from the speed control means 13 by the boosting means 12. It is a power amplification means for amplifying the voltage at a constant amplification rate based on the voltage and applying a drive voltage to each electrode of the piezoelectric body to supply power.

FIG. 5 shows a circuit example of the boosting means 12 of FIG. 4, and C is a charging / discharging capacitor. FIG. 6 shows a boosting means
Boost voltage (a) and drive voltage (c) when 12 is turned on and off
FIG. 7 is a waveform diagram showing the relationship of (b), and FIG.
6 is a flowchart showing the steps of the arithmetic processing of FIG.

The operation of the ultrasonic motor control device of the second embodiment having the above-described structure will be described below with reference to the drawings.

The target speed setting means 8 outputs the target speed of the moving body 26 to the speed control means 13. Immediately after being turned on, the boosting means 12 gradually charges the boosted voltage as shown in FIG. 6 (a) while the capacitor C of FIG. 5 is being charged, and immediately after being turned off, while the capacitor C is being discharged, as shown in FIG. 6 (a). As shown in, the boosted voltage gradually decreases.

The speed control means 13 performs arithmetic processing to
The frequency of the frequency signal is controlled so that the moving speed of 26 reaches the target speed, and the boosting means 12 is turned on during stoppage and intermittent driving.
Performs OFF control and outputs frequency signals with 90 ° different phases. When these frequency signals are amplified by the power amplifying means 14 and 15 at a constant amplification rate based on the boosted voltage boosted by the boosting means 12 and applied to the ultrasonic motor 1, the vibrating body 23 vibrates and the moving body moves. 26 is driven. The vibration amount of the vibrating body 23 is output to the speed control means 13 through the vibration amount detecting means 2 as the speed information detecting means and the A / D converting means 3.

The speed control means 13 performs the arithmetic processing shown in FIG. 7 based on this vibration amount and the speed command value output from the target speed setting means 8. The processing will be described below in the order of the flowchart. To do.

In step S22, the target speed of the moving body 26 set by the target speed setting means 8 is read in step S23.
Proceed to. In step S23, it is checked whether the target speed of the moving body 26 is 0 (at the time of stop). If it is 0, the process proceeds to step S24, and if it is not 0, the process proceeds to step S25. In step S24, the boosting means 12 is turned off and the process proceeds to step S22. In step S25, the voltage boosting means 12 is turned on and step S
Proceed to 26.

In step S26, the target vibration amount corresponding to the target speed of the moving body 26 is read from the information storage means 7 and the process proceeds to step S27. In step S27, it is checked whether or not the target speed of the moving body 26 has changed. If it has changed, the process proceeds to step S22, and if not, the process proceeds to step S28. In step S28, the current vibration amount of the vibrating body 23 is read, and the process proceeds to step 29. In step S29, it is checked whether or not the drive is intermittent, and if the drive is intermittent, the process proceeds to step S30. If the drive is continuous, the process proceeds to step S31.

In step S30, the current moving speed of the moving body 26 is estimated from the current vibration amount read in step S28, and the ON / OFF cycle or ON / OFF ratio of the booster 12 is changed according to the moving speed. It proceeds to step S31.

In step S31, the difference between the target vibration amount read in step S26 and the current vibration amount read in step S28 is calculated, a speed error is calculated, and the process proceeds to step S32.
In step S32, the speed error obtained in step S31 is 0.
It is estimated whether the current moving speed of the moving body 26 is slower than the target speed by comparing with the larger value. If it is slow, the process proceeds to step S33, and if it is fast, the process proceeds to step S34. In step S33, arithmetic processing is performed, the drive frequency is lowered, and the process proceeds to step S27. In step S34, arithmetic processing is performed, the drive frequency is increased, and the process proceeds to step S27.

In this way, the moving speed of the moving body 26 is controlled to reach the target speed.

As described above, according to the second embodiment, the ON / OFF control of the boosting means 12 is performed at the time of intermittent driving, and this O
By utilizing the voltage change caused by charging / discharging the capacitor C of the boosting means 12 at the time of N, OFF, and applying the changed drive voltage to the ultrasonic motor, it is possible to control the drive voltage by the microcomputer unlike the conventional case. It is possible to smooth the change in the moving speed, prevent the generation of sound and vibration, and reduce the processing load on the microcomputer.

In each of the above embodiments, the case where the speed information of the moving body 26 is detected from the vibration quantity of the vibrating body 23 by the vibration quantity detecting means 2 as the speed information detecting means has been described.
It goes without saying that the object of the present invention can be achieved even when speed information is detected by using an encoder, a magnetic sensor, or the like.

[0053]

As described above, according to the first aspect of the invention, during intermittent driving, the moving amount of the moving body is always controlled to be the maximum moving amount that smoothly moves according to the moving speed. The operation can be smooth even during intermittent drive as in continuous drive, and the number of starts and stops can be minimized to reduce loss during start and stop and reduce power consumption. You can

The invention according to claim 2 turns on the boosting means when starting the ultrasonic motor and turns on the boosting means when the ultrasonic motor is stopped.
FF is used, and by utilizing the voltage change due to charging and discharging of the capacitor of the boosting means generated at the time of ON and OFF, and applying the changed drive voltage to the ultrasonic motor, the conventional control of the drive voltage by the microcomputer is performed. It is possible to smooth the change in the moving speed without any operation, prevent the generation of sound and vibration, and reduce the processing load on the microcomputer. Further, by turning off the boosting means at the time of stop, it is possible to reduce the loss in the boosting means and reduce the power consumption.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a control device for an ultrasonic motor according to a first embodiment of the present invention.

FIG. 2 is a flowchart showing a process of arithmetic processing of the speed control means of FIG.

FIG. 3 is a flowchart showing a process of a calculation process of the drive cycle control means of FIG.

FIG. 4 is a block diagram showing a configuration of an ultrasonic motor control device according to a second embodiment of the present invention.

5 is a circuit diagram of a booster unit shown in FIG.

6 is a waveform diagram showing the relationship between the boosted voltage and the drive voltage when the boosting means of FIG. 4 is turned on and off.

FIG. 7 is a flowchart showing a process of arithmetic processing of the speed control means of FIG.

FIG. 8 is a partially cutaway perspective view of a conventional annular ultrasonic motor.

9 is an explanatory diagram showing vibration displacement in a radial direction of a vibrating body of the annular ultrasonic motor of FIG.

FIG. 10 is an explanatory diagram showing the operating principle of the ultrasonic motor.

FIG. 11 is a characteristic diagram showing the relationship between the amount of vibration of the ultrasonic motor and the moving speed.

FIG. 12 is a waveform diagram showing timings of a drive signal and a moving speed during the conventional intermittent drive.

FIG. 13 is a characteristic diagram showing the relationship between the moving speed of the ultrasonic motor and the maximum moving amount that moves smoothly.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Ultrasonic motor, 2 ... Speed information detection means (vibration amount detection means), 3, 5 ... A / D conversion means, 4 ... Position information detection means, 6 ... Drive cycle control means, 7 ... Information storage means, 8 ... target speed setting means, 9, 13 ... speed control means, 10, 11, 14, 15 ... power amplifying means, 12 ... boosting means, 16 ... microcomputer, 23 ... vibrating body, 26 ... moving body.

Claims (4)

[Claims] 1. A vibrating body comprising an elastic body and a piezoelectric body driven by a frequency voltage, and a moving body placed in contact with the vibrating body, and exciting an elastic wave to the vibrating body. A speed information detecting unit that detects information about a moving speed of the moving body as a control unit of an ultrasonic motor that moves the moving body, a position information detecting unit that detects information about a moving position of the moving body, and Based on the output information of the target speed setting means for setting the target speed of the moving body and the speed information detecting means, the frequency of the frequency voltage is controlled so that the moving speed of the moving body becomes the target speed, and intermittently. Speed control means for setting a maximum movement amount for smoothing the movement amount of the moving body at one time according to the moving speed of the moving body at the time of driving; Speed control hand An ultrasonic motor control device comprising: a drive cycle control means for controlling a drive cycle based on output information of the position information detection means so as to obtain the set value of the step. 2. A vibrating body composed of an elastic body and a piezoelectric body driven by a frequency voltage, and a moving body placed in contact with the vibrating body to excite elastic waves on the vibrating body. A speed information detecting means for detecting information about a moving speed of the moving body as a control means of an ultrasonic motor for moving the moving body, a target speed setting means for setting a target speed of the moving body, and the ultrasonic wave. The frequency of the frequency voltage is controlled so that the moving speed of the moving body becomes the target speed on the basis of boosting means for boosting the power supply voltage for driving the motor to a constant level and output information of the speed information detecting means. And, at the time of starting and stopping, the boosting means is turned on and off.
A control device for an ultrasonic motor, comprising: speed control means for performing F control. 3. The ultrasonic motor control device according to claim 1, wherein an encoder, a magnetic sensor or the like is used in place of the vibration amount detecting means as the speed information detecting means. 4. The ultrasonic motor control device according to claim 2, wherein an encoder, a magnetic sensor or the like is used in place of the vibration amount detecting means as the speed information detecting means.