JP2003134856A - Drive and control unit for vibration wave actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the rotational speed of a vibration wave actuator from being abruptly increased, immediately after the actuator is started. SOLUTION: When a vibration wave motor is at a stop (YES in S2), a frequency fb, equivalent to the revolution of the vibration wave motor being zero, is outputted (S3). Thus, when the vibration wave motor is started next, a cyclic voltage to be applied to an electrical-mechanical energy conversion element is generated, based on the frequency fb (S1), and as a result, the rotational speed of the motor is prevented from increasing abruptly.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration wave actuator drive control device, and more particularly, to a vibrating body composed of an electro-mechanical energy conversion element and an elastic body, and a mover arranged in pressure contact with the vibrating body. The present invention relates to a drive control device for a vibration wave actuator, which controls the moving speed or the rotation speed of the vibration wave actuator including the above.

[0002]

2. Description of the Related Art Conventionally, a drive control apparatus for a vibration wave motor, which includes a vibrating body composed of an electro-mechanical energy conversion element and an elastic body, and a moving element arranged in pressure contact with the vibrating body, has been disclosed, for example. It is known from JP-A-3-18282. Such a drive control device determines a frequency of a frequency voltage to be applied to the electro-mechanical energy conversion element, and applies it to the electro-mechanical energy conversion element based on a frequency signal output from the frequency determination section. And a frequency generator that generates a power frequency voltage, and the rotation speed of the vibration wave motor is determined according to the frequency of the frequency voltage applied to the electromechanical energy conversion element. The rotation speed of the vibration wave motor is controlled by changing the frequency of the voltage.

[0003]

However, in the above-mentioned conventional vibration wave motor, when the operation of repeating the start and stop is performed, the frequency voltage output from the frequency determining unit when the rotation of the vibration wave motor is stopped last time is changed. Frequency
If the frequency corresponds to a high rotation speed, the vibration wave motor will rotate at a high speed at the moment it is started, resulting in a problem that smooth start cannot be obtained.

FIG. 5 is a diagram showing changes in the rotational speed of a conventional vibration wave motor when the start and stop are repeated.

Even if the same speed command as the first time is issued the second time after the first change in the rotation speed as shown by the waveform C1,
At the second time, a change in the rotation speed, such as the waveform C2, in which the rotation speed sharply increases immediately after startup occurs.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a vibration wave actuator drive control device in which the rotation speed is prevented from rapidly increasing immediately after starting.

[0007]

In order to achieve the above object, according to the invention of claim 1, a vibrating body composed of an electro-mechanical energy conversion element and an elastic body is brought into pressure contact with the vibrating body. In a drive control device of a vibration wave actuator for controlling a moving speed or a rotation speed of a vibration wave actuator provided with a moving element arranged as follows, a frequency of a frequency voltage to be applied to the electro-mechanical energy conversion element is determined and output. Frequency determining means, voltage generating means for generating a frequency voltage to be applied to the electromechanical energy conversion element based on the frequency output by the frequency determining means, and re-operation after stopping the driving of the vibration wave actuator. At the time of starting, before the restart operation is started, the frequency determining means is set Vibration actuator drive control device is provided which is characterized in that an output control means for outputting have frequency.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of a vibration wave motor drive control device according to the present invention.

In the figure, 1 is a microcomputer, 2 is a memory connected to the microcomputer 1, and the memory 2 stores a control program executed by the microcomputer 1. The microcomputer 1 has a memory 2
Create and output a digital command value based on the control program stored in.

Reference numeral 3 denotes a D / A converter, which converts the digital command value output from the microcomputer 1 into an analog voltage. 4 is a V / F converter, which is a D / A converter 3
The analog voltage value output from is converted into a frequency signal.
Reference numeral 5 denotes a voltage application unit that performs waveform shaping on the frequency signal output from the V / F converter 4 and adjusts the voltage value of the frequency signal according to a command from the microcomputer 1 to generate the vibration wave motor 6 Output to.

Although not shown in the drawings, the vibration wave motor 6 includes a vibrating body composed of an electro-mechanical energy conversion element (for example, a piezoelectric element) and an elastic body, and a mover arranged in pressure contact with the vibrating body. When the frequency signal is applied to the electro-mechanical energy conversion element, the vibrating body vibrates progressively, and thereby the mover rotates.

Reference numeral 7 denotes a rotary encoder which detects the rotation angle coordinates of the moving element of the vibration wave motor 6 and outputs a pulse signal. Reference numeral 8 denotes a counter, which counts the cumulative number of pulses of the pulse signal output from the rotary encoder 7 and outputs it as position information to the microcomputer 1.

The microcomputer 1 creates a digital command value based on the cumulative number of pulses sent from the counter 8 and the desired rotation speed of the vibration wave motor 6 instructed from the outside.

FIG. 2 is a diagram showing the relationship between the frequency of the frequency signal input to the vibration wave motor 6 and the rotation speed of the vibration motor 6.

In the vibration wave motor 6, the vibration body amplitude changes according to the frequency of the frequency signal, and the motor rotation speed changes accordingly. In particular, a frequency band on the higher frequency side than the resonance frequency at which the rotation speed becomes maximum is used for drive control of the vibration wave motor 6, and the motor rotation speed becomes zero at the frequency fa.

When it is desired to smoothly start the vibration wave motor 6, the frequency fa or a frequency fb higher than this is set as the initial frequency, and the energization to the vibration wave motor 6 is started. Then, the frequency is gradually scanned toward the low frequency side so as to approach the desired rotation speed.

By the way, when the vibration wave motor 6 is started and then stopped and restarted, a rapid change in the rotation speed conventionally occurs as shown in FIG. The cause will be described with reference to FIG.

FIG. 3 is a diagram showing changes in the rotational speed that are considered to occur in the vibration wave motor 6 when the inertia of the vibration wave motor 6 is assumed to be very small.

After starting and stopping the vibration wave motor 6 for the first time, the VF converter 4 holds the output frequency at the time of the first stop. Even if the microcomputer 1 outputs the command of the initial frequency fb at the time of the second activation, there is a response time delay in the VF converter 4, and this is unavoidable. Therefore, immediately after the activation, the VF converter 4 is The output frequency at the first stop is output to the voltage applying unit 5. As a result, when the vibration wave motor 6 stops rotating for the first time, the frequency of the frequency voltage output from the VF converter 4 is
When the frequency corresponds to a high rotation speed, the waveform C4 shown in FIG.
After a momentary rapid increase in speed, a change in the rotation speed is returned to the original rotation speed corresponding to the frequency fb.

It is considered that such a change in the rotation speed as shown by the waveform C4 in FIG. 3 becomes like the waveform C2 in FIG. 5 in the vibration wave motor 6 having a large inertia.

Therefore, in the present invention, immediately after the vibration wave motor 6 is stopped, the microcomputer 1 outputs the command of the frequency fb corresponding to the rotational speed of zero to output the VF converter 4.
The frequency held by is set to fb.

FIG. 4 is a flow chart showing the procedure of the rotational speed control processing of the vibration wave motor 6 executed by the microcomputer 1.

In step S1, the microcomputer 1 creates a digital command value based on the cumulative number of pulses sent from the counter 8 and the desired rotation speed of the vibration wave motor 6 instructed from the outside.

In step S2, it is determined whether or not there is an external instruction to stop the rotation of the vibration wave motor 6. If there is an instruction, the process proceeds to step S3, and if there is no instruction, the process returns to step S1.

In step S3, the frequency fb is commanded to be output, and this processing is terminated.

As a result, when the vibration wave motor 6 is started next time, the output frequency of the VF converter 4 has already become the frequency fb corresponding to the rotational speed of zero, so that the start-up is performed as shown by the waveform C2 in FIG. Sometimes the speed does not increase sharply and a smooth start can be achieved.

In the processing shown in FIG. 4, when the rotation of the vibration wave motor 6 is stopped, the microcomputer 1 operates at the frequency f.
Although b is commanded to be output, in the present invention, if after the rotation stop of the vibration wave motor 6 and before the rotation start,
The microcomputer 1 may output the frequency fb as an instruction at any time.

Further, in the above embodiment, the rotation of the vibration wave motor has been described as an example, but it goes without saying that the present invention can be applied to general vibration wave actuators that move or rotate.

Further, the vibration wave motor drive control device in the above-described embodiment may be configured by hardware or software, and when the function of the vibration motor drive control device is realized by software. In the above, a storage medium storing a program code of software that realizes the functions of the above-described embodiments is supplied to the system or apparatus, and the computer (or CPU or MPU) of the system or apparatus is stored in the storage medium. It goes without saying that the present invention can also be achieved by reading and executing the program code.

In this case, the program code itself read from the storage medium realizes the function of the above-described embodiment, and the storage medium storing the program code constitutes the present invention.

As a storage medium for supplying the program code, for example, a floppy (registered trademark) disk,
Hard disk, optical disk, magneto-optical disk, CD-
ROM, CD-R, magnetic tape, non-volatile memory card, ROM, etc. can be used.

Further, by executing the program code read by the computer, not only the functions of the above-described embodiments are realized, but also the OS or the like running on the computer is executed based on the instruction of the program code. Needless to say, the present invention includes a case where a part or all of the actual processing is performed and the functions of the above-described embodiments are realized by the processing.

Further, after the program code read from the storage medium is written in the memory provided in the function expansion board inserted into the computer or the function expansion unit connected to the computer, based on the instruction of the program code, It goes without saying that the present invention also includes a case where the CPU or the like included in the function expansion board or the function expansion unit performs some or all of the actual processing and the processing realizes the functions of the above-described embodiments. .

[0035]

As described above in detail, according to the present invention, the frequency determining means for determining and outputting the frequency of the frequency voltage to be applied to the electro-mechanical energy conversion element, and the frequency output by the frequency determining means. Based on the above, voltage-generating means for generating a frequency voltage to be applied to the electro-mechanical energy conversion element, and when the vibration wave actuator is restarted after the drive is stopped, before the restart operation is started, Output control means for outputting a frequency higher than the frequency at which the wave actuator starts moving or rotating is provided.

As a result, in the vibration wave actuator, it is possible to prevent the driving speed from rapidly increasing immediately after starting, and it is possible to realize smooth starting.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of a vibration wave motor drive control device according to the present invention.

FIG. 2 is a diagram showing the relationship between the frequency of the frequency signal input to the vibration wave motor and the rotation speed of the vibration motor.

FIG. 3 is a diagram showing a change in rotational speed that is considered to occur in the vibration wave motor, assuming that the inertia of the vibration wave motor is very small.

FIG. 4 is a flowchart showing a procedure of rotational speed control processing of a vibration wave motor executed by a microcomputer.

FIG. 5 is a diagram showing changes in rotation speed in a conventional vibration wave motor when starting and stopping are repeated.

[Explanation of symbols]

1 Microcomputer (frequency determination means, voltage generation means, output control means) 2 Memory (frequency determination means, voltage generation means, output control means) 3 D / A converter (frequency determination means, output control means) 4 V / F Converter (frequency determination means, output control means) 5 Voltage application section (voltage generation means) 6 Vibration wave motor (vibration wave actuator) 7 Rotary encoder (frequency determination means) 8 Counter (frequency determination means)

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Eiichi Yanagi             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation (72) Inventor Makoto Shiomi             2-4-19 Nakane, Meguro-ku, Tokyo Kyano             Within Seiki Co., Ltd. F-term (reference) 5H680 AA09 BB03 BB15 CC07 DD02                       DD23 DD53 DD62 EE22 FF25                       FF30

Claims (3)

[Claims] 1. A moving speed or a rotating speed of a vibration wave actuator having a vibrating body including an electro-mechanical energy conversion element and an elastic body, and a moving element arranged in pressure contact with the vibrating body. In a drive control device for an oscillating wave actuator, a frequency determining unit that determines and outputs a frequency of a frequency voltage to be applied to the electro-mechanical energy conversion element, and the electric-electrical unit based on the frequency output by the frequency determining unit. Voltage generation means for generating a frequency voltage to be applied to the mechanical energy conversion element, and before the restart operation start at the time of restarting after the drive stop of the vibration wave actuator, to the frequency determining means,
A vibration wave actuator drive control device comprising: an output control unit that outputs a frequency higher than a frequency at which the vibration wave actuator starts moving or rotating. 2. The vibration wave actuator drive control device according to claim 1, wherein the output control means causes the frequency determining means to output the frequency immediately after the driving of the vibration wave actuator is stopped. 3. The vibration wave actuator drive control device according to claim 1, wherein the vibration wave actuator repeats starting and stopping continuously.