Position control device and position control method for machine tools

Abstract

A machine tool moves a driven member by use of a servomotor. A position control device controls the position of the driven member in accordance with full closed loop control. The position control device computes an integrated feedback value g in correspondence with a function F (V M , P M , V m , P m ) in which four state amounts, motor speed V M , motor position P M , driven member speed V m , and driven member position P m are independent variables. The thrust instruction Ä*, which is inputted to the servomotor, is compensated with the integrated feedback value g. The servomotor is thus optimally driven and controlled in accordance with full closed loop control.

Description

technical field [0001] The present invention relates to an improved machine tool position control device and method, wherein the servo motor is optimally driven and controlled according to full closed loop control. Background technique [0002] Conventionally, position control devices for machine tools are known. A machine tool includes a servo motor serving as a driving member and a member serving as a driven member driven by the driving member, such as a slide shaft. More specifically, the drive of the sliding shaft is controlled according to servo control (including full-closed loop control and semi-closed-loop control). In the control loop of the full-closed control, feedback control is performed on data indicating the position of a driven part of the machine tool such as a table, which is detected by a position detection device such as an optical scale. [0003] In the control loop of the semi-closed control, feedback control is performed on position data obtained by ...

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Problems solved by technology

[0004] However, since the full-closed-loop control acts directly on the machine tool, if the stiffness of the machine tool is relatively low, a relatively small position loop gain needs to be set compared with the semi-closed-loop control

In this case, the response of the driven part to the control will be destroyed, which will lead to relatively poor dynamic performance (including contouring accuracy) of the driven part

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