JPH02174579A - Digital servo control - Google Patents

Abstract

PURPOSE:To improve the positioning accuracy of an apparatus by detecting the torque of a motor being driven and by correcting a drive command value in a real time basis according to a torque variation. CONSTITUTION:A digital servo control is composed of an operation command system 101, a digital servo control system 102, a drive system 105, a movement detection system, and a torque detection system 108. Also, the control system 102 is equipped with a torque variation-compensating part 103, an amplifier 104, a correction value-changing table 107, etc. The compensating part 103 estimates and inputted torque T to obtain a quantity of torque variation and to select the correction value C from the table 107 which has been set beforehand.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a digital servo control device, particularly a digital servo control device that automatically adjusts a drive command value to a desired value in response to torque fluctuations in a drive system. This invention relates to a digital servo control device.

[Conventional technology]

A conventional digital servo control device includes an operation command system for outputting a movement command value for instructing a desired operation, and a digital servo control system for inputting the movement command value from the movement command system and outputting a drive system command value. The digital servo control system includes a servo control system, a drive system that performs a specified operation by inputting the drive system command value, and a movement detection system that detects the operation of the drive system and outputs a movement amount. However, the movement command value was inputted, and the drive system command value amplified with a constant gain was output as is.

[Problem to be solved by the invention]

The conventional digital servo control device described above outputs a drive system command value that is amplified by a movement command value with a constant gain, and Kane focused on stability during driving when the load is constant. In robot control, etc., changes in posture and panning of objects with large weights are
When the load condition applied to the motor changes due to a ring or the like, there is a drawback that stability and positioning accuracy deteriorate. a movement command system for outputting a movement command value for commanding;
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; a movement detection system that detects movement and outputs a movement amount; a torque detection system that detects the torque of the drive system; and a torque fluctuation compensation unit that corrects the drive command value by looking up a correction value for torque fluctuation. It is configured to include a value 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.

The torque fluctuation compensator 103 evaluates the torque T input from the torque detection system 108, calculates the torque fluctuation amount from 1 to 1, and calculates the torque fluctuation amount from the correction value switching table 107 in which the correction value corresponding to the rough torque fluctuation amount is set. , select the correction value C.

The digital servo control system 102 is a movement command system that commands a desired movement], and calculates a deviation E from the movement command value P input from 01 and the movement amount B input from the movement amount detection system 106, and sends it to the amplification unit 104. .

In the amplifier 104, the deviation E is amplified using the cane G, and the correction value C is added to obtain the drive system command value X, which means the terminal voltage of the DC servo motor, and the drive system 1
Output to 05.

The movement amount detection system 106 detects the movement amount of the drive system 105 and sends it to the technical support system 02.

Torque detection system 108 detects the amount of torque of drive system 105 and sends it to torque compensator 103 .

Next, the correction value switching operation will be explained.

As a characteristic of a DC servo motor, the relationship between the torque T applied to the motor and the motor terminal voltage is determined by the induced voltage constant Ke, which is a constant unique to the motor, the torque constant I(t, and the viscous damping coefficient K).
d, armature resistance Ra, brush voltage drop Vb, friction torque Tf, and motor rotational speed ω as a variable indicating the state of the motor.

Assuming that the sampling time Tm is constant, the motor rotation speed ω is calculated from the movement amount B as follows: ω-B/Tm... (
2). Here, when the motor terminal voltage V is constant and the torque T varies, the rotational speed ω changes accordingly. That is, the amount of movement B changes, and the desired operation cannot be obtained. In order to keep the rotational speed 0 constant, the motor terminal voltage (2) is corrected in response to the fluctuations in the torque T.

The torque fluctuation compensator 103 calculates the torque fluctuation Te from the deviation between the torque at the previous sampling time and the current torque, refers to the correction value switching table 107, and selects the correction value switching table 107 that is closest to the torque fluctuation Te obtained by the calculation. Select the correction value C corresponding to the torque fluctuation value in .

〔Effect of the invention〕

The digital servo device of the present invention detects the torque of the motor being driven and corrects the drive command value to real tightness according to the torque fluctuation, thereby reducing the change in the moving speed in response to the motor load fluctuation. This has the effect of improving positioning accuracy.

[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...1~Lux fluctuation compensation section, 104...Amplification section, 1-05...Drive system, 106...Movement amount detection system,
107...Correction value switching table, 108.Torque detection system, X...Drive command value, B...Movement amount, C...Correction value,
G: Gain, P: Operation command value, E: Deviation between operation command value and travel amount, T: Drive system torque.

Claims (1)

[Claims] a movement command system for outputting a movement command value for instructing a desired movement; a digital servo control system for inputting the movement command value from the movement command system and outputting a drive system command value; and a digital servo control system for outputting a drive system command value. A drive system including a DC servo motor that performs a specified operation by inputting a system command value, a movement detection system that detects the operation of the drive system and outputs the amount of movement, and a torque detection system that detects the torque of the drive system. What is claimed is: 1. A digital servo control device comprising: a torque fluctuation compensator that corrects the drive command value by looking up a correction value for torque fluctuation; and a correction value switching table.