JPH11150962A - Drive circuit for ultrasonic motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drive circuit which makes it possible to control the speed of an ultrasonic motor, over a wide speed range from minute smooth operation up to powerful high-speed operation. SOLUTION: On the basis of a command speed value inputted from a speed commanding section 42 for issuing a command speed for an ultrasonic motor 11, the number of driving pulses is outputted from a driving-pulse-number storing table 43, and a voltage of each driving pulse is outputted from an applied- voltage-value storing table 44. Using both of these, the number of the driving pulses and the applied voltage of each driving pulse, the speed of the ultrasonic motor 11 is controlled by an ultrasonic-motor-drive control unit 45.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving circuit for an ultrasonic motor used as various driving devices for precision machines and optical instruments.

[0002]

2. Description of the Related Art Recently, an ultrasonic motor is used as a driving source of various driving devices for precision machines and optical instruments, for example, a driving source of a micromanipulator for finely manipulating a subject using an operating needle under a visual field of a microscope. Used.

[0003] Such ultrasonic motors are broadly classified into rotary type and linear type motors, and both types are capable of obtaining high torque while being smaller in size than conventional electromagnetic motors. Has the advantage of

[0004] Conventionally, as a driving circuit of this kind of ultrasonic motor, there is known a driving circuit disclosed in Japanese Patent Application Laid-Open No. Hei 8-130889. This publication discloses a vibrator having an elastic body and an electro-mechanical energy conversion element fixed to the elastic body, and applying a driving signal to the electro-mechanical energy conversion element to generate ultrasonic vibration on the surface. FIG. 15 shows a driving circuit of an ultrasonic motor composed of a driven body which is pressed against the surface of the vibrator and is moved with respect to the vibrator by ultrasonic vibration. As shown in FIG. Is specified, a command analysis unit 1 that analyzes data into a data format that can be processed in the drive circuit, an application pattern storage unit 2 in which an application amount according to the command is stored in a table, and a displacement direction of the ultrasonic motor 8 are determined. The phase determining unit 3, the oscillator 4 for resonating the ultrasonic transducer in the ultrasonic motor 8, and the amount of application obtained by the application pattern storage unit 2 in the displacement direction determined by the phase determining unit 3. Cycle pulse generator 5 to force, cycle pulse generator 5
The power amplifiers 6 and 7 amplify the output voltage of the power amplifier 6 and the ultrasonic motor 8 driven by the output voltages from the power amplifiers 6 and 7.

[0005] In such a configuration,
When a position command is output from a controller (not shown),
The command is input to the command analysis unit 1, and the command analysis unit 1
The position command is converted into signed data, and the timing at which the position command is input is determined by the cycle pulse generator 5.
Inform The signed position command data is input from the command analysis unit 1 to the applied pattern storage unit 2 and the phase determination unit 3. The application pattern storage unit 2 converts the input position command data into unsigned integer data, and refers to the integer data as an address, for example, a data table as shown in FIG. Is input to the cycle pulse generator 5. The cycle pulse generator 5 determines the number of drive pulses based on the data corresponding to the address in the data table, so that the desired operation of the ultrasonic motor 8 is obtained.

Japanese Unexamined Patent Publication No. Hei 8-98568 discloses an ultrasonic motor driving device in which an ultrasonic motor has an imbalance in the displacement amount in the moving direction due to the imbalance of the pressing force between the ultrasonic vibrator and the moving body. By utilizing the occurrence of balance, the desired operation of the ultrasonic motor can be obtained by changing the number of drive pulses depending on the moving direction or changing the voltage value applied to the piezoelectric element of the ultrasonic motor according to the moving direction. ing.

[0007]

However, the desired thrust and speed can be obtained by changing only the driving pulse for operating the ultrasonic motor as described above, or applied to the ultrasonic vibrator of the ultrasonic motor. The following problems occur when the desired thrust and speed are obtained by changing only the applied voltage.

First, in a method in which only a drive pulse is changed to operate an ultrasonic motor, a vibrator is vibrated by applying a drive pulse having a frequency near a resonance point of the ultrasonic motor, and is pressed against the surface of the vibrator. Move the driving body. Since the frequency of the resonance point in this case is in the ultrasonic range, for example, if a frequency of about 55.5 KHz is used, the operating speed of the ultrasonic motor is increased, that is, the frequency is applied to the ultrasonic motor. Even if the number of drive pulses is increased, the maximum value is limited to the number of pulses corresponding to the resonance frequency of the ultrasonic vibrator. Therefore, the maximum number of pulses at this time is 55,500 pulses per second.

When the ultrasonic motor is driven by an appropriate applied voltage, the operation amount increases as the number of drive pulses applied per unit time increases, and the moving distance per unit time, that is, the speed, increases. . However, in a control in which 55,500 pulses are output per second, for example, when an operation instruction is given using a rotary encoder, the operation amount is too large for one pulse of the rotary encoder, and the following operation is performed. The response of the ultrasonic motor to one pulse from the rotary encoder slows down,
It becomes impractical.

Further, when such an ultrasonic motor is applied to a micromanipulator for finely manipulating a subject using an operating needle under the field of view of a microscope, the ultrasonic motor has an extremely fine and smooth movement of the operating needle. To the coarse movement operation that operates at high speed, and because the fine operation when operating the cell does not allow any movement of the operation needle, the ultrasonic motor has a very small number of drive pulses. Will be applied. However, even if a very small number of drive pulses are applied, if the movement of the operation needle is at an unacceptable level, the circuit of the drive circuit is modified to reduce the applied voltage of the drive pulse of the ultrasonic motor. However, in this case, there is a possibility that it is impossible to cope with the coarse movement operation that operates at a high speed, and the usability is deteriorated.

On the other hand, when the number of drive pulses applied to the ultrasonic motor is fixed and only the applied voltage is changed, the number of drive pulses applied to the ultrasonic motor is set in advance to be small, and By lowering the applied voltage, it is possible to reduce the movement of the operation needle in the fine operation state when operating the cell. However, the number of drive pulses is fixed at a small value, and the maximum rating of the voltage that can be applied to the ultrasonic motor is also determined.In the coarse movement operation that operates the operation needle at high speed, the voltage applied to the ultrasonic motor is set to the maximum rating. However, if the desired operating speed cannot be obtained, the operating speed higher than that can only be given up.

The present invention has been made in view of the above circumstances, and provides a drive circuit for an ultrasonic motor that can realize a wide range of operation speed control from a fine and smooth operation to a high-speed operation with power. The purpose is to:

[0013]

According to the first aspect of the present invention,
In the drive circuit of the ultrasonic motor that translates the driven body by exciting the expansion and contraction operation and the bending vibration along the longitudinal direction of the rectangular parallelepiped elastic body using the piezoelectric element as a drive source, the operation speed of the ultrasonic motor is adjusted. Operating speed instructing means for instructing, converting means for converting the number of driving pulses input to the ultrasonic motor and an applied voltage value of the driving pulse based on the speed indicating value input from the operating speed indicating means; And an ultrasonic motor control means for controlling the operation speed of the ultrasonic motor based on the number of drive pulses output from the means and the applied voltage value of the drive pulse.

According to a second aspect of the present invention, in the first aspect, the conversion means uses the speed instruction value input from the operation speed instruction means as an address to correspond to the number of driving pulses and the applied voltage value of the driving pulse. It consists of a table to be output.

According to a third aspect of the present invention, in the second aspect, the table is provided with a plurality of regions in which the number of drive pulses with respect to the speed instruction value and the degree of change in the applied voltage value of the drive pulse are different.

As a result, according to the first aspect of the present invention,
By varying the number of drive pulses input to the ultrasonic motor and the applied voltage value of the drive pulse in combination, it is possible to realize a wide range of operation speed control of the ultrasonic motor from fine and smooth operation to high-speed operation with power.

According to the second aspect of the present invention, a stable operation speed control is performed by using the number of drive pulses output from the table and the applied voltage value of the drive pulse for the speed instruction value from the operation speed instruction means. Can be realized.

According to the third aspect of the present invention, a desired operation speed of the ultrasonic motor can be obtained by selecting an area in the table according to the purpose of use of the ultrasonic motor.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. 1 to 3 illustrate an ultrasonic motor applied to the present invention. FIG. 1 is a side view showing a schematic configuration of the ultrasonic motor, and FIG. FIG. 3 schematically shows a bending operation of the ultrasonic motor.

In FIG. 1, reference numeral 11 denotes an ultrasonic motor. The ultrasonic motor 11 generates a translational motion by using a piezoelectric element, which is an electromechanical conversion element, as a drive source. The basic elastic body 12 has a rectangular parallelepiped shape. A pair of piezoelectric elements 13
1 and 131 are arranged via the holding elastic body 14, and a pair of sliding members 151 and 1 are provided on the lower surface of the basic elastic body 12.
When a sine wave voltage is applied to the piezoelectric elements 131, 131, the basic elastic body 12 is provided as shown in FIG.
Is excited along the longitudinal direction of the elastic body, and at the same time, as shown in FIG. 3, the bending vibration of the transverse wave composed of the secondary standing wave propagating in the longitudinal direction of the basic elastic body 12 is excited. Has become.

In this case, the length and width dimensions of the basic elastic body 12 are set so that the temporary resonance frequency of the stretching vibration and the frequency of the secondary bending vibration, which is a transverse wave, coincide with each other. At the maximum bending point of the standing wave (the position of the antinode of the vibration), the displacement of the stretching vibration and the bending vibration is combined, and the mass point on the basic elastic body 12 moves along the elliptical trajectory. Of the sliding members 151, 151 at the maximum bending point of
The driven body (not shown) pressed by 1 can be translated. 16 is the ultrasonic motor 1
The support pins are planted at positions of the basic elastic body 12 that serve as nodes of ultrasonic vibration.

FIG. 4 shows a schematic configuration of a micromanipulator applied to such an ultrasonic motor.
In the figure, reference numeral 21 denotes an inverted microscope.
Reference numeral 1 denotes an illumination light source 23 above the stage 22 and a stage 2
2 and the objective lens 24 is disposed below the
An illumination light from the illumination light source 23 is radiated to the subject, for example, the cells S contained in the container 25 on the top 2, and an observation image of the cells S is taken into the objective lens 24 from below the stage 22, and an optical system (not shown) The eyepiece can be visually observed by being guided to an eyepiece through the lens.

A micromanipulator 27 is provided for such a microscope 21. The micromanipulator 27 has a base end portion of an operation needle 272 fixed to a manipulator body 271.
71 is provided near the stage 22 by a jig (not shown), and the cells S in the container 25 can be operated by the operation needle 272.

FIGS. 5 and 6 further illustrate such a micromanipulator 27. FIG. 5 is an exploded perspective view, and FIG. 6 is a perspective view. In FIG. 5, the manipulator body 271 has a frame 28 having a U-shaped cross section and a cutout 280 formed from the front to the back of the opposing side surface.
The ultrasonic motor 11 is arranged in the inside 8.

The ultrasonic motor 11 has a support pin 16 implanted at a position of the basic elastic body 12 which serves as a node of ultrasonic vibration so as to be rotatable between a pair of holding bodies 301 provided on a support 29. Supported. The support 29 has a pair of guide pillars 311, 311 in the support direction of the basic elastic body 12, and these guide pillars 311, 311 are provided in holes 281, 281 formed on the upper surface of the frame 28, and ball bushes 321, 32.
By inserting the ultrasonic motor 1 through the first motor 1, the ultrasonic motor 11 can be translated only in the direction in which the ultrasonic motor 11 is urged.

On the back surface of the frame 28, a support arm 33 is provided. The support arm 33 has its tip bent at 90 ° and is arranged to face the upper surface of the support 29. A pedestal 34 is provided at the tip of the support arm 33, and a coil spring 35 is inserted between the pedestal 34 and the upper surface of the support 29, and the ultrasonic motor 11 is inserted by the coil spring 35 through the support 29. In addition to applying a pressing force for urging the basic elastic body 12 to the movable portion 36 described later, the pressing force at this time can be adjusted by the pedestal 34.

The notch 280 of the frame 28 has a movable portion 36
Is movably provided. The movable portion 36 has a rectangular plate shape, and has a convex portion 361 along the longitudinal direction of the lower surface center portion. The convex portion 361 is supported by the linear guide 37, and extends along the linear guide 37. It is possible to move linearly. Further, a sliding plate 38 is provided along the longitudinal direction of the upper surface of the movable portion 36. The sliding members 151 of the basic elastic body 12 of the ultrasonic motor 11 are pressed against the sliding plate 38 by the pressing force of the coil spring 35 so that the sliding members 151 and 151 are frictionally driven by the elliptical vibration of the sliding members 151. Has become.

The manipulator main body 271 of the micromanipulator 27 thus configured is disposed so that the movable portion 36 faces upward as shown in FIG.
The operation needle 272 attached to the movable portion 36 is driven.

Returning to FIG. 4, the micromanipulator 2
7, a drive circuit 40 is connected to the manipulator body 271, and an input unit 41 and an operation speed instruction unit 42 are connected to the drive circuit 40.

The input unit 41 has a built-in rotary encoder 411 for converting a rotary motion into an electric signal. By rotating a rotary knob (dial) 412 provided on a shaft of the rotary encoder 411, the input unit 41 can correspond to the rotation angle. A pulse indicating the driving direction and a signal indicating the driving direction are output.
The operation speed instruction unit 42 has a built-in rotary switch 421. The rotary switch 421 has, for example, a 6-bit output terminal.
One rotation of the rotary knob 422 provided on one axis outputs 64-step speed instruction values "0" to "63" as 6-bit data. The rotary switch 421 has a click mechanism (not shown). When the rotary knob 422 is rotated, the click mechanism operates at each stage, and a desired rotation position can be set. The drive circuit 40 is for driving the micromanipulator 27, and outputs a drive signal for causing the ultrasonic motor 11 to generate displacement based on the speed instruction value by the input unit 41 and the speed instruction unit 42. Has become.

FIG. 7 shows a schematic configuration of the drive circuit 40. In this case, the drive circuit 40 includes a drive pulse number storage table 43, an applied voltage value storage table 44, an ultrasonic motor drive control unit 45, a DAC 46, and a drive circuit 47.

The driving pulse number storage table 43 is shown in FIG.
(A) As shown in (b) and (c), the table is composed of a ROM in which the relation between the ROM address and the number of driving pulses is stored in a table. The speed instruction value for driving with R
The number of drive pulses corresponding to the OM address is output. Applied voltage value storage table 44
Is a ROM in which the relationship between the ROM address and the applied voltage value is stored in a table as shown in FIGS. 9 (a), 9 (b) and 9 (c).
The speed instruction value for driving the ultrasonic motor 11 output from the operation speed instruction unit 42 at a desired speed is used as a ROM address, and the applied voltage value of the corresponding drive pulse is output. ing. The ultrasonic motor drive control unit 45 includes a crystal oscillator (not shown), a rotary dip switch for finely adjusting the resonance frequency of the ultrasonic motor 11, a PLL circuit serving as a basis for generating the resonance frequency of the ultrasonic motor 11, and all operations. FPG to control
A and the like, and the data of the number of drive pulses and the applied voltage value of the drive pulse output from the drive pulse number storage table 43 and the applied voltage value storage table 44 are stored in the FPG
A is latched in a register inside A, and is loaded into a down counter (not shown) for counting the number of driving pulses,
Further, the ultrasonic motor 11 sent from the input unit 41
In accordance with the driving direction and the operation start instruction signal, a CMOS level four-phase drive pulse is output to the drive circuit 47 and digital data of the applied voltage of the drive pulse applied to the ultrasonic motor 11 is output to the DAC 48. I have to.

The DAC 48 includes an ultrasonic motor drive controller 4
5 converts the digital data of the applied voltage of the drive pulse applied to the ultrasonic motor 11 into an analog signal and outputs it to the drive unit 47. Here, a 12-bit one is used. The drive unit 47 includes an FE (not shown).
A drive signal is output to the ultrasonic motor 11 based on a drive pulse from the ultrasonic motor drive control unit 45 and analog data of an applied voltage from the DAC 48. ing.

FIGS. 10A, 10B and 10C show the relationship between the four-phase drive pulses output from the ultrasonic motor drive controller 45 and the drive signals generated by the drive circuit 47. FIG. 4A shows an ultrasonic motor drive control unit 4.
P1 to P in the case where the number of drive pulses output from 5 is three
4 shows four-phase drive pulses. here,
The frequency of each phase is 55.5 KHz, and one cycle is 18 μs. Further, these four-phase driving pulses P1 to P4
Are the driving pulses P1 and P1 as shown in FIGS.
2, P3 and P4 are paired, and the ultrasonic motor 1
Drive signals AS and BS for generating ultrasonic vibration of one of the piezoelectric elements 131 are generated.

Here, one drive pulse is the minimum number of pulses for exciting the ultrasonic motor 11 in a state in which each of P1 to P4 in FIG. In addition, the peak values of the drive signals AS and BS in FIGS. 10B and 10C change according to the magnitude of the analog data output from the DAC 48.

Next, the operation of the embodiment configured as described above will be described. First, the user turns the rotary knob 422 of the operation speed instruction unit 42 to specify a desired operation speed value from among 64 speed instruction values of “0” to “63”. For example, if “9” is instructed as the speed instruction value, 6-bit binary number “001001” data is output from the operation speed instruction unit 42 to the drive circuit 40.

In the drive circuit 40, when a speed instruction value is input from the operation speed instruction section 42, the speed instruction value is stored in the ROM.
FIG. 8 of the drive pulse number storage table 43 as an address
9 and the corresponding applied voltage value is output from the table shown in FIG. 9 of the applied voltage value storage table 44, and these output data are input to the ultrasonic motor drive control unit 45. .

In this case, the driving pulse number storage table 43
As shown in FIG. 11, the number of drive pulses stored in the area has a plurality of (three) areas in which the degree of change in the number of drive pulses C with respect to the speed instruction value A is different. Similarly, as shown in FIG. 12, the applied voltage value stored in the applied voltage value storage table 44 has a plurality of (three) areas where the degree of change of the applied voltage value B with respect to the speed instruction value A is different. ing. Accordingly, when the user performs a small operation such as bringing the operation needle 272 of the micromanipulator 27 into contact with the cell S or piercing the cell membrane, the speed instruction value A is shown in FIGS. X-D
To enter the area.

With such an instruction, the vibration of the operation needle 272 can be suppressed to a level where it is hardly seen. When the moving speed of the operation needle 272 is finely adjusted while maintaining this state, the number of drive pulses can be slightly changed without changing the voltage applied to the ultrasonic motor 11. The speed can be adjusted while suppressing the vibration of the operation needle 272, and an extremely fine and smooth movement of the operation needle 272 can be obtained.

In a case where the user searches for a target cell in a high-magnification visual field by using the operating needle 272, if the vibration is kept low and a speed higher than that between X and D is required, 11 and 12, an instruction is given so that the speed instruction value A falls within the area indicated by DE in the figure.

By giving such an instruction, the ultrasonic motor 11
Since the applied voltage gradually rises in a low state, the vibration is suppressed to a low level, and the operating needle 272 does not jump out of the field of view due to a high magnification.

In the case where the user searches for a target cell in a low magnification field of view with the operation needle 272, a slight vibration is allowed and the movement of the operation needle 272 is required to be faster than between D and E. In such a case, in FIG. 11 and FIG. 12, an instruction is given so that the speed instruction value A falls between the illustrated EF.

By giving such an instruction, the ultrasonic motor 11
, And the number of drive pulses also increases sharply, and some vibration is applied to the operation needle 272, but a quick movement of the operation needle 272 is obtained.

When an extremely high-speed operation that is not used during cell operation, such as when the user replaces the operation needle 272, is required, the speed instruction value A is shown in FIGS. Instruct to enter the area of G.

By giving such an instruction, the ultrasonic motor 11
, The operating needle 272 can move at high speed. That is, in such a case, the applied voltage value storage table 4 is determined by the speed instruction value A of the operation speed instruction unit 42.
4 is increased to a maximum of "63". Then, the input value to the DAC 46 becomes “4095”, and the maximum rated voltage is applied to the ultrasonic motor 11. here,
The voltage range that can be applied to the ultrasonic motor 11 is 0 V to 10 V
Then, the output voltage of the DAC 46 becomes 0 V when the speed instruction value is “0”, and becomes 10 V when the speed instruction value is “4095”. Of course, when the speed instruction value A of the operation speed instruction unit 42 becomes “63” at the maximum, the number of drive pulses in the drive pulse number storage table 43 also increases rapidly.

The speed instruction value A of the operation speed instruction section 42
Becomes maximum “63” and the voltage value applied to the ultrasonic motor 11 becomes “4095” as the input value of the DAC 46,
If a higher operation speed is required, it can be realized by increasing the number of drive pulses in the drive pulse number storage table 43 from the current level.

In this way, by giving the speed instruction value A of the operation speed instruction unit 42 according to the purpose of use of the operation hand 272, the drive pulse number storage table 43 and the applied voltage value storage table 44 are read from the same address. The operating speed of the ultrasonic motor 11 is determined from the data of the driving pulse number and the applied voltage of the driving pulse.

On the other hand, when the rotary knob 412 of the input section 41 is rotated, the input section 41 outputs, for example, the signal shown in FIG.
A two-phase drive pulse as shown in (b) is output and input to the ultrasonic motor drive controller 45. In this case, FIG.
In (a) and (b), the phase relationship between the A phase and the B phase is reversed. Here, when the B-phase pulse is delayed from the A-phase pulse as shown in FIG. 7A, an instruction to drive the operating needle 272 in a direction to approach the cell S is given. )
When the A-phase pulse lags behind the B-phase pulse as shown in (1), an instruction to drive the operation needle 272 away from the cell S is issued. That is, in the case of FIG. 13A, when the ultrasonic motor drive control unit 45 detects the rising of the A-phase pulse, the level of the B-phase pulse at this time is confirmed. In this case, the level of the B-phase pulse is L.
The ultrasonic motor 11 is driven in a direction to bring the cell closer to the cell S.

In this state, assuming that the current speed instruction value of the operation speed instruction section 42 is “9”, the number of drive pulses “13” from the drive pulse number storage table 43 and the applied voltage value The value “150” is read out, and the ultrasonic motor drive control unit 45 reads the value
In the manner described above, the drive pulses P1 to P4 are output by the number of drive pulses "13" every time the signal of the A-phase pulse rises, and the applied voltage value is "150" (= 0.56).
A drive signal corresponding to V) is output from the DAC 46,
As a result, the ultrasonic motor 1
1 is driven, and the operation needle 2 of the micromanipulator 27 is
The reference numeral 72 drives the cell S at a predetermined speed.

FIG. 14A shows the phase relationship between the four driving pulses of the ultrasonic motor 11 when the operation needle 272 approaches the cell S. FIG. 14B shows the operation needle 272 moving away from the cell S. The phase relationship between the four-phase drive pulses of the ultrasonic motor 11 in the case is shown.

The maximum value of the number of drive pulses written in the drive pulse number storage table 43 is set so that the output is completed in a sufficiently short time with respect to the rising cycle of the A-phase pulse. The number of rotations of the rotary knob 412 of the input unit 41, which can be considered by the use of, is not problematic at all.

Accordingly, the ultrasonic motor 1
Drive pulse number storage table 4 based on the speed instruction value input from operation speed instruction unit 42 for instructing the operation speed 1
3, the driving pulse number and applied voltage value storage table 44
Since the applied voltage value of the drive pulse is output, the operation speed of the ultrasonic motor 11 is controlled by the ultrasonic motor drive control unit 45 using both the number of drive pulses and the applied voltage value of the drive pulse. It is possible to realize a wide range of operation speed control of the ultrasonic motor 11 from fine and smooth operation to high-speed operation with power.

The number of drive pulses and the applied voltage value of the drive pulse output from the drive pulse number storage table 43 and the applied voltage value storage table 44 based on the speed instruction value input from the operation speed instruction section 42 are used. Thus, stable operation speed control can be realized.

Further, since the drive pulse number storage table 43 and the applied voltage value storage table 44 are provided with a plurality of areas having different degrees of change in the number of drive pulses and the applied voltage value of the drive pulse with respect to the speed instruction value, By selecting an optimal area according to the purpose of use of the motor 11, a desired operation speed of the ultrasonic motor 11 can be easily obtained.

In the above-described embodiment, the operation speed of the operation needle 272 of the micromanipulator 27, that is, the operation speed of the ultrasonic motor 11 is set to a desired value by the operation speed instruction unit 42, so that the optimum micro-manipulator 27 is set. The manipulator operation has been realized.
Means for individually setting the number of drive pulses and the applied voltage value of the drive pulse can be provided. By doing so, the Z-axis of the micromanipulator 27,
In other words, although some vibrations are allowed, if you want to move slowly and the movement is vertical to the sample, reduce the drive pulse to a few pulses when you need a considerable thrust, etc. By setting the applied voltage to a very high value, a desired operation can be realized. Also,
If this is applied to the motorized stage of a microscope using an ultrasonic motor, it is possible to easily realize a setting that does not change the operation feeling even if the weight of the sample placed on the stud fluctuates. The stage can be operated in a wide speed range and thrust as in the case of.

[0056]

As described above, according to the present invention, by changing the number of driving pulses input to the ultrasonic motor and the applied voltage value of the driving pulse to be variable, the ultrasonic motor can be extremely reduced in vibration. A wide range of operations from fine and smooth operation to high-speed operation with power can be supported.

Further, since the number of drive pulses output from the table and the applied voltage value of the drive pulse are used for the speed instruction value from the operation speed instruction means, stable operation speed control can be realized. Furthermore, by selecting a region in the table according to the purpose of use of the ultrasonic motor, a desired operation speed of the ultrasonic motor can be easily obtained.

[Brief description of the drawings]

FIG. 1 is a side view showing a schematic configuration of an ultrasonic motor applied to an embodiment of the present invention.

FIG. 2 is a diagram schematically showing a telescopic movement operation of the ultrasonic motor applied to one embodiment.

FIG. 3 is a diagram schematically showing a bending operation of the ultrasonic motor applied to one embodiment.

FIG. 4 is a diagram showing a schematic configuration of a micromanipulator applied to one embodiment;

FIG. 5 is an exploded perspective view of the micromanipulator applied to the embodiment;

FIG. 6 is a perspective view of a micromanipulator applied to one embodiment.

FIG. 7 is a diagram illustrating a schematic configuration of a driver circuit applied to one embodiment;

FIG. 8 is a diagram showing a driving pulse number storage table applied to one embodiment;

FIG. 9 is a diagram showing an applied voltage value storage table applied to one embodiment;

FIG. 10 is a diagram showing an output waveform of an ultrasonic motor drive control unit applied to one embodiment.

FIG. 11 is a diagram illustrating a relationship between a speed instruction value A and a drive pulse number C in a drive pulse number storage table applied to one embodiment;

FIG. 12 is a diagram showing a relationship between a speed instruction value A and an applied voltage value B in an applied voltage value storage table applied to one embodiment;

FIG. 13 is a diagram showing an output waveform of an input unit applied to one embodiment.

FIG. 14 is a diagram showing a phase relationship between four-phase drive pulses of the ultrasonic motor according to the embodiment;

FIG. 15 is a diagram showing a schematic configuration of a driving circuit of a conventional ultrasonic motor.

FIG. 16 is a diagram showing a data table used in a drive circuit of a conventional ultrasonic motor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Ultrasonic motor, 12 ... Basic elastic body, 131 ... Piezoelectric element, 14 ... Elastic body for holding, 151 ... Sliding member, 16 ... Support pin, 21 ... Microscope, 22 ... Stage, 23 ... Light source for illumination, 24 ... Objective lens, 25 ... Container, 27 ... Micromanipulator, 271 ... Manipulator main body, 272 ... Operation needle, 28 ... Frame, 280 ... Notch, 281 ... Hole, 29 ... Support, 301 ... Holding body, 311 ... Guide pillar, 321, ball bush, 33, support arm, 34, pedestal, 35, coil spring, 36, movable part, 361, convex part, 37, linear guide, 38, sliding plate, 40, drive circuit, 41 ... Input unit, 411: rotary encoder, 412: rotary knob, 42: operating speed instruction unit, 421: rotary switch, 422: rotary knob, 4 ... driving pulse number storage table 44 ... applied voltage value storage table, 45 ... ultrasonic motor drive control unit, 46 ... DAC, 47 ... drive circuit.

Claims (3)

[Claims] 1. A driving circuit for an ultrasonic motor that translates a driven body by exciting a stretching operation and a bending vibration along a longitudinal direction of a rectangular parallelepiped elastic body using a piezoelectric element as a driving source, Operating speed instructing means for instructing the operating speed of the motor; and conversion for converting the number of driving pulses input to the ultrasonic motor and the applied voltage value of the driving pulse based on the speed indicating value input from the operating speed indicating means. Means for controlling the operation speed of the ultrasonic motor according to the number of drive pulses output from the conversion means and the applied voltage value of the drive pulse. circuit. 2. The apparatus according to claim 1, wherein the conversion means comprises a table for outputting the number of driving pulses and the applied voltage value of the driving pulse corresponding to the speed instruction value input from the operation speed instruction means as an address. 2. A drive circuit for the ultrasonic motor according to claim 1. 3. The drive circuit for an ultrasonic motor according to claim 2, wherein the table has a plurality of regions in which the number of drive pulses and the degree of change in the applied voltage value of the drive pulse with respect to the speed instruction value are different. .