Actuator control device, robot system, actuator control program, recording medium, and actuator control method

Abstract

A command velocity V2 (second velocity command) corresponding to a difference between a rotational position θi and a rotational position θo is generated, and a command velocity V3 is generated on the basis of a command velocity V1 and the command velocity V2. Specifically, the rotational position θo of a joint 21 and the rotational position θi of a rotating shaft 331 of a motor 33 are acquired, and the command velocity V1 is corrected on the basis of the command velocity V2 corresponding to the difference between the rotational position θo and the rotational position θi. Then, a command torque Tm is generated in accordance with the command velocity V3 generated by such correction. Thus, the generation of vibration caused by the positional deviation of the joint 21 with respect to the rotating shaft 331 (output shaft) of the motor 33 is suppressed, thereby achieving high-speed response.

Claims

1. An actuator control device that provides a drive command to an actuator that drives a workpiece connected to an output shaft by moving the output shaft in response to the drive command, comprising: a workpiece detection position acquisition unit that acquires the workpiece detection position output by a workpiece position detection unit that detects the position of the workpiece and outputs a workpiece detection position; a first speed command generation unit that generates a first speed command indicating a target speed of the output shaft according to the difference between the workpiece detection position and the target position of the output shaft indicated by the position command; a second speed command generation unit that generates a second speed command according to the positional displacement of the workpiece with respect to the output shaft; a third speed command generation unit that generates a third speed command based on the first speed command and the second speed command; and a drive command generation unit that generates the drive command according to the third speed command.

2. The actuator control device according to claim 1, wherein the second speed command generation unit calculates a positional displacement amount indicating the positional displacement of the workpiece with respect to the output shaft, and generates the second speed command by adding a value obtained by multiplying the positional displacement amount by a predetermined position gain and a value obtained by multiplying the derivative of the positional displacement amount by a predetermined speed gain.

3. The actuator control device according to claim 2, wherein the position gain and the velocity gain are determined based on a target value for the damping coefficient and a target value for the peak frequency, respectively.

4. The actuator control device according to any one of claims 1 to 3, wherein a positional displacement generating unit is provided between the output shaft of the actuator and the workpiece, which causes a positional displacement of the workpiece relative to the output shaft.

5. The actuator control device according to claim 4, wherein the positional displacement generating unit includes at least one of a reduction gear and a torque sensor.

6. An actuator control device according to any one of claims 1 to 5, comprising a filter that performs signal processing on the signal of the peak frequency in the frequency response characteristics of the position of the workpiece with respect to the first speed command, which attenuates signals of a frequency different from the peak frequency, and which generates the second speed command by performing the signal processing by the filter with respect to the positional displacement of the workpiece with respect to the output shaft.

7. The actuator control device according to claim 6, wherein the filter is a low-pass filter, a band-pass filter, or a high-pass filter.

8. A robot system comprising a robot arm and an actuator control device according to any one of claims 1 to 7 for controlling actuators that drive the joints of the robot arm.

9. An actuator control program that causes a computer to function as an actuator control device according to any one of claims 1 to 7.

10. A recording medium for recording the actuator control program described in claim 9 in a manner readable by a computer.

11. An actuator control method that provides a drive command to an actuator that drives a workpiece connected to an output shaft by moving the output shaft in response to the drive command, comprising: a step of acquiring the workpiece detection position output by a workpiece position detection unit that detects the position of the workpiece and outputs the workpiece detection position; a step of generating a first speed command indicating a target speed of the output shaft according to the difference between the workpiece detection position and the target position of the output shaft indicated by the position command; a step of generating a second speed command according to the positional displacement of the workpiece with respect to the output shaft; a step of generating a third speed command based on the first speed command and the second speed command; and a step of generating the drive command according to the third speed command.

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