JPH0595685A - Driver for ultrasonic motor - Google Patents

Abstract

PURPOSE:To provide a driver which can control an ultrasonic motor, which is not special, to a set rotating speed. CONSTITUTION:Data regarding a speed is applied from a speed setter 7 to a microcomputer 1. A driving current of a certain driving frequency is applied by a digital signal applied from the microcomputer 1 to rotate a motor 11, and its rotating speed is sent as data to the microcomputer 1 via a rotation sensor 5. A digital output value when data obtained from the sensor 5 coincides with data obtained from the setter 7 is stored in a memory 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improvement of a driving device for an ultrasonic motor.

[0002]

2. Description of the Related Art A conventional method of driving a commercially available ultrasonic motor (hereinafter referred to as a motor) is one in which the motor and the driving device are
The drive frequency and the like of the drive device attached to the motor were adjusted in pairs. This is because the variable frequency range of the ultrasonic motor is narrow, and if it exceeds a certain frequency (which is in the vicinity of the drive frequency that maximizes the rotation speed), the rotation direction of the motor reverses or abnormal noise is generated. Is. In addition, since the frequency characteristics of the motor also vary, even if the drive frequency of a certain motor has a rotation speed within an appropriate range, if another motor is connected, the rotation direction will be reversed or abnormal noise will occur as described above. Sometimes occurred.

[0003]

Conventionally, as described above, since the motor and the driving device are paired, it is necessary to readjust the driving device when replacing the motor, and the motor and the driving device are required for mass production. There was a problem with the management of. Moreover, when the motor fails, the drive unit must be replaced.

An object of the present invention is to provide a drive device capable of controlling a set rotation speed even if the motor changes.

[0005]

An ultrasonic motor driving apparatus according to the present invention includes a means for detecting the rotation speed of the motor, a means for setting the rotation speed, and a rotation speed of the motor for the set rotation speed. A means for outputting a control signal for matching and a means for storing the drive frequency corresponding to the set rotation speed are provided.

[0006]

Since the present invention has the above-described structure, it is possible to store the drive frequency corresponding to the set rotation speed of the motor connected in advance, and to prevent variations in motor characteristics and load. Absorbing changes in rotation speed due to differences,
It can be controlled at the set rotation speed under any circumstances.

[0007]

FIG. 1 is a block diagram of an embodiment of the present invention.

The microcomputer section 1 forms a loop with the voltage conversion section 2, the voltage frequency conversion section 3, the drive section 4, the motor 11, the rotation detection section 5 and the like. Further, the microcomputer unit 1 is connected to a storage unit 8 having a test operation unit 6, a speed setting unit 7, and a backup unit 9. Further, the power supply unit 10 supplies power to each unit.

The voltage conversion section 2 converts the digital output from the microcomputer section 1 into an analog value (for example, an 8-bit digital signal is converted into 256 kinds of analog values). The voltage frequency conversion unit 3 includes the voltage conversion unit 2
The frequency corresponding to the analog value of is generated. The drive unit 4 receives electric power of a certain drive frequency from the voltage frequency conversion unit 3 and drives the motor 11 at a certain speed. The rotation detection unit 5 detects the rotation speed of the motor 11 and inputs a signal to the microcomputer unit 1. The microcomputer unit 1 centrally manages and controls the device.

The test operation unit 6 is for setting the test operation, the speed setting unit 7 is for setting the rotation speed of the motor, and the storage unit 8 corresponds to the set rotation speed. The optimum digital value from the microcomputer unit 1 for outputting the driving frequency is stored. Further, the backup unit 9 retains the contents of the storage unit 8 even when the power is cut off.

The microcomputer section 1 adjusts and outputs a digital output so that the rotation speed of the motor 11 approaches a set value in response to an input signal from the rotation detection section 5,
As a result, the output frequency of the voltage frequency converter 3 changes,
The drive frequency of the motor changes and the rotation speed of the motor changes. With such a loop, it functions to match the rotation speed of the motor 11 with the set value. Rotation detector 5
For example, a rotary encoder is used to detect the rotation of the motor, and a signal corresponding to the detected value is input to the microcomputer unit 1.

In actual use, first, the test operation unit 6 sets a test state, and the microcomputer unit 1 outputs a digital output that minimizes the rotation speed, and then a digital output that sequentially increases the rotation speed. Is changed and the digital output value at the time when the rotational speed matches the value set by the speed setting unit 7 is stored in the storage unit 8 and the test operation is ended.

Since the digital output value corresponding to the drive speed set in advance in the storage unit 8 is stored, the operation time at the next start can be shortened.

FIG. 2 is a flow chart when the test operation is set. First, in step S100, a test operation is set.

When the test operation is set, the microcomputer section 1 outputs a rotation start signal and a digital output corresponding to a slow rotation speed (step S101). The rotation speed of the motor is detected (step S
102), comparing with the speed setting value (step S103),
If the detection speed is slow (step S106), the digital output is incremented by 1 and output again (step S107). If the detection speed is high, the digital output is decremented by 1 and output again (step S108).

This loop is repeated, and when the speed detection value matches the set speed, the value of the digital output at that time is stored in the storage unit 8 as the set rotation speed control value (step S104), and the test operation ends. Yes (step S1
05).

FIG. 3 is a flow chart during normal operation. When a rotation start signal is input from the ON switch or the like of the device in the standby state (step S201), the microcomputer unit 1 reads the digital control value of the set rotation speed from the storage unit 8 (step S202), A digital value is output (step S203).

The rotation detector 5 detects the rotation speed (step S204), and determines whether the rotation speed matches the speed setting value (step S205). If the input from the rotation detection unit 5 agrees with the speed set value, it is driven as it is, and if the value from the speed detection unit 5 is later than the set value (step S
209) and adds 1 to the digital value (step S21
0), if the speed is high, the digital value is decremented by 1 (step S211), and the speed is controlled to approach the set value.

In step S206, it is determined whether or not there is a stop signal. If there is no stop signal, the rotation continues, and if there is a stop signal, the rotation continues (step S20).
7). Then, in the next step S208, the optimum digital output value at that time is stored.

Thus, at the end of the normal operation, the optimum digital output value at that time is stored in the storage unit 8 as the latest value.
Remember it again. This is to cope with changes in environmental conditions such as temperature, changes in load, etc., and always perform optimum control.

In the test operation and the normal operation, the change of the digital value is explained as plus / minus one. However, when the difference from the set value is large, the change value is increased and the speed is controlled so as to quickly match the set speed. it can.

Control of the motor requires forward or reverse control, and the load condition differs between forward and reverse, and the optimum digital value often differs. In such a case, the optimum digital values for forward rotation and inversion are stored in the storage unit
Need to remember. Further, when there are many speed settings, it is necessary to store the optimum digital value suitable for each speed setting.

[0023]

As described above, according to the present invention, it is possible to perform control so that a preset drive speed can be obtained by a test operation with respect to variations in frequency of ultrasonic motors, load fluctuations, and the like. Further, the optimum control value is updated for each operation, so that optimum control can always be performed. Therefore, management at the time of mass production and maintenance after installation become easy, and its economical effect is great.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

FIG. 2 is a flowchart of a test operation.

FIG. 3 is a flowchart of normal operation.

[Explanation of symbols]

 1 Microcomputer part 2 Voltage conversion part 3 Voltage frequency conversion part 4 Driving part 5 Rotation detection part 6 Test operation part 7 Speed setting part 8 Storage part 11 Motor

Claims (1)

[Claims] 1. A means for detecting the rotation speed of the ultrasonic motor, a means for setting the rotation speed of the ultrasonic motor, and a control signal for matching the rotation speed of the ultrasonic motor with the set rotation speed. And a means for storing a drive frequency corresponding to a set rotation speed, the ultrasonic motor drive device.