JPH01236303A - Digital servo controller - Google Patents

Abstract

PURPOSE:To reduce the variation of the moving speed of a moving object caused by the load fluctuation of a motor so as to improve the positioning accuracy of the object by estimating the torque of the motor being driven from the feedback of the moving quantity of the object and the command value of a driving system and converting a gain at real time in accordance with the torque. CONSTITUTION:When the induced voltage constant, torque constant, viscous braking factor, armature resistance, brush voltage drop, frictional torque, which are constants inherent to a motor, are respectively represented by Ke, Kt, Kd, Ra, Vb, and Tf and the motor rotating speed and motor terminal voltage are respectively represented by (w) and large V as variables indicating the state of the motor, the torque T applied to the motor is expressed by equation I. Moreover, the rotating speed (omega) of the motor is expressed by omega=B/Tm. A gain switching section 103 finds the torque T from the above-mentioned formula by using the command value X of a driving system and moving quantity B at the previous sampling time given from a digital servo controlling system 102.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a digital servo control device that automatically adjusts the gain value of the digital servo control device to a desired value.

[Conventional technology]

In a conventional digital servo control device, there is a motion command system for outputting a movement command value for instructing a desired motion, and a drive system command value is output by inputting the movement command value from the movement command system. a digital servo control system; a drive system that performs a specified operation by inputting the drive system command value;
a movement detection system that detects the operation of the drive system and outputs a movement amount, and the digital servo control system inputs the movement command value and outputs a drive system command value amplified with a constant gain. was.

[The problem that the invention attempts to solve]

The conventional digital servo control device described above amplifies the movement command value with a constant gain and outputs the drive system command value. Since this method is determined based on the focus, there is a drawback that stability and positioning accuracy deteriorate when the load conditions applied to the motor change due to changes in posture, handling of heavy objects, etc. in robot control etc. Ta.

[Means to solve the problem]

The digital servo control device of the present invention includes an operation command system for outputting a movement command value for commanding a desired operation;
a digital servo control system that inputs the movement command value from the operation command system and outputs a drive system command value; a drive system that inputs the drive system command value and performs a specified operation; and an operation of the drive system. a movement detection system that detects a movement amount and outputs a movement amount, the digital servo control system evaluates the movement amount and the drive command value, and calculates a gain value for torque by table lookup. By looking up,
The gain switching section includes a gain switching section that performs stepwise switching and a gain switching table.

〔Example〕

Next, embodiments of the present invention will be described in detail with reference to the drawings.

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

In FIG. 1, the digital servo control system 102 sends the movement ftB input from the movement amount detection system 106 and the drive command value X at the time of the previous sample to the gain switching unit 103.
The gain switching unit evaluates the drive command value X at the time of movement 1B and the previous sample, and selects the gain G from the gain switching table 107 in which gain values corresponding to torques are set in advance. The digital servo control system 102 calculates the deviation E from the movement command value P input from the movement command system 101 that commands a desired operation and the movement amount B input from the movement amount detection system 106 and sends it to the amplification section 104. . In the amplifying section 104, the deviation E is amplified with a gain G to obtain a drive system command value X, which means the terminal voltage of the DC servo motor, and outputted to the drive system 105.
Remember.

The movement amount detection system 106 detects the movement amount of the drive system 105 and sends it to the digital servo system 102.

Next, the gain switching operation will be explained.

As a characteristic of a DC servo motor, the torque T applied to the motor K is determined by an induced voltage constant Ke, a torque constant Kt, and a viscous braking coefficient Kd, which are constants unique to the motor.

Armature resistance Ra, brush voltage drop vb1 friction torque Tf
, and motor rotational speed ω and motor terminal voltage V as variables indicating the state of the motor.

...(1) If the sampling time Tm is constant, the movement -jt
From B, the motor rotation speed ω is as follows: ω=B/Tm...(
2). Further, the motor terminal voltage V is given from the drive system command value XK. According to equations (1) and (2), it can be seen that if the drive system command value X and the movement amount B are given, the torque applied to the motor K can be found.

The gain switching unit 103 is a digital servo control system 10.
Torque T is determined by calculating equations (2) and (1) using drive system command value X and movement amount B at the time of the previous sample given by Yoshishi.

Next, the gain switching unit 103 refers to the gain switching table 107 and then calculates the torque T calculated by the above calculation.
The gain G corresponding to the torque in the gain switching table 107 that is closest to that is selected.

By estimating the torque of the motor using the feedback of the travel amount and the drive system command value, and converting the gain in real time according to the torque, changes in the travel speed due to motor load fluctuations are reduced, and positioning accuracy is improved. There is an effect.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention. 101... Operation command system, 102... Digital servo control system, 103... Gain switching unit, 1o4... Amplifying unit, 105... ...
Drive system, 106・Old...Movement detection system, 107...
...Gain switching table. Agent: Susumu Uchihara, patent attorney/l) 2 Diagram 1

Claims (1)

[Claims] a movement command system for outputting a movement command value for instructing a desired movement; and a digital servo for inputting the movement command value from the movement command system and outputting a drive system command value meaning the terminal voltage of the motor. A digital servo device comprising a control system and a movement detection system that detects the operation of a drive system including a DC servo motor that performs a specified operation by inputting the drive system command value and outputs a movement amount, The digital servo control system evaluates the movement amount and the earlier drive system command value,
1. A digital servo control device comprising a gain switching section and a gain switching table that stepwise switches gain values for torque by table lookup.