JPH04314108A - Controller for robot - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a teaching playback type robot control device.

0002

[Prior Art] In recent years, robot control devices have been using the proportional-integral control method to stably control the speed of servo motors that operate at a constant speed or accelerate or decelerate rapidly in accordance with the speed command value given from a position control device. I am using it.

Conventionally, a control device for this type of robot generally had a configuration as shown in FIG. As shown in the figure, the speed command value 2 created by the position control device 1 is
In the speed control device 3, the difference between the speed command value 2 and the operating speed 5 output from the speed generating section 4 is taken as a speed deviation 6. The current command value 10 is obtained by taking the sum of the speed deviation 6 multiplied by the speed proportional gain 7 and the speed deviation 6 multiplied by the speed integral gain 8 and the time accumulation 9. This current command value 10 passes through a current control unit 11 and a power circuit 12, drives a servo motor 13, and passes through a reducer 14 to a robot arm 1.
Operate 5. A position detector 16 receives a signal from the servo motor 13 and detects the operating position.

0004

However, in the above conventional configuration, the speed proportional gain 7 and the speed integral gain 8
was set to a fixed value, so setting speed proportional gain 7 to a large value makes it easier to respond to sudden command changes, but speed fluctuations may occur due to small operating speed detection errors during constant speed operation. When set, it is not affected by small motion speed detection errors because it is accumulated over time, but since a time delay occurs in response to a sudden speed command value 2, an articulated robot using a reducer 14 with relatively low rigidity However, there was a problem in that residual vibrations were likely to occur.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems, and aims to provide a robot control device that can improve stability at constant speed and reduce residual vibrations during sudden acceleration and deceleration.

[0006]

[Means for Solving the Problems] In order to achieve the above object, the present invention includes a servo motor coupled to a robot arm, a speed control device for controlling the speed of the servo motor by a proportional integral control method, and a speed control device for controlling the speed of the servo motor using a proportional integral control method. a position control device that controls the position of the servo motor by giving a speed command value to a speed control device, and the position control device controls the speed according to a time differential value of the speed command value while the robot is in a playback operation. The configuration is such that adaptive control is performed to change the speed proportional gain and speed integral gain in the proportional integral control section of the device.

[0007]

[Operation] In the above configuration, the speed proportional gain and the speed integral gain are changed and controlled based on the data map in accordance with the motion acceleration of the robot arm.

[0008]

Embodiment An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. In this embodiment, the same components as those shown in the above-mentioned conventional example are given the same reference numerals, and the explanation thereof will be omitted.

As shown in the figure, a microprocessor is used for the position control device 20, and one device can control six points of an articulated robot.
It controls the axis. Furthermore, one digital signal processor is used for the two-axis speed control device 21 and current control section 22 of the articulated robot. Three are used to control the 6-axis articulated robot. A shared memory is provided between this digital signal processor and the microprocessor of the position control device 20 to communicate speed command values 2 and other parameters.

While the articulated robot is operating, the position control device 20 controls the speed command value 2 at position control time intervals (approximately 3 m).
s), and each time the speed command value 2 is created, the difference from the previous speed command value 2 (approximately 3 ms ago) is calculated and used as the acceleration. Further, a data map showing the relationship between the acceleration/velocity proportional gain and the acceleration/velocity integral gain as shown in FIG. 2 is created in the memory of the position control device 20. This was experimentally determined from the behavior at constant speed and rapid speed changes. The position control device 20 calculates a velocity proportional gain 23 at each position control time interval based on the calculated acceleration and the data map.
and speed integral gain 24 are calculated and written into the shared memory together with the speed command value. The speed control device 21 receives the speed command value 2 and speed proportional gain 2 written in the shared memory by the position control device 20 at every speed control time interval (approximately 0.8 ms).
3 and velocity integral gain 24, and position detector 1.
The speed generator 4 generates an operating speed 5 from the operating position 17 detected in step 6, and calculates a current command value 10 using the proportional-integral control method. After the current command value 10, the robot arm 15 is driven using the same control method as in the conventional example.

In this way, the speed proportional gain 23 and the speed integral gain 24 are adjusted according to the motion acceleration of the robot arm 15.
By performing adaptive control to change the speed control device 2
1 can be digitized, making it easier to exchange data.

0012

Effects of the Invention As is clear from the description of the embodiments above, the robot control device of the present invention has a servo motor coupled to a robot arm, and a speed control system that controls the speed of the servo motor using a proportional-integral control method. and a position control device that controls the position of the servo motor by giving a speed command value to the speed control device, and the position control device responds to the time differential value of the speed command value while the robot is in a playback operation. This system performs adaptive control that changes the speed proportional gain and speed integral gain in the proportional-integral control section of the speed control device.With this configuration, when the speed command value changes suddenly, the servo control is adjusted according to the command. The motor can be rotated and operated at a constant speed without speed fluctuation when the command value is constant, improving speed stability at constant speed and reducing residual vibrations during sudden acceleration/deceleration.

[Brief explanation of drawings]

[Fig. 1] Block diagram of a robot control device of the present invention

[Figure 2] (a) Data map of acceleration/velocity proportional gain of the same control device (b) Data map of acceleration/velocity integral gain of the same control device

[Figure 3] Block diagram of a conventional robot control device

[Explanation of symbols]

2 Speed command value 13 Servo motor 15 Robot arm 20 Position control device 21 Speed control device 23 Speed proportional gain 24 Speed integral gain

Claims (1)

[Claims] 1. A servo motor coupled to a robot arm, a speed control device that controls the speed of the servo motor using a proportional-integral control method, and a speed command value given to the speed control device to control the position of the servo motor. and a position control device for controlling a speed proportional gain and a speed integral gain in a proportional-integral control section of the speed control device according to a time differential value of a speed command value while the robot is in a playback operation. A robot control device characterized by performing adaptive control to change.