Suppression of Limit Cycles in Servo Systems Using Gain Limit Compensator

Abstract

In high-precision positioning systems, the limit cycles induced by friction effects result in a significant reduction in the positioning performance; particularly when the servo system utilizes a high gain controller. Accordingly, the current study presents a compensation scheme consisting of a dead-zone function and an integral term to limit the equivalent gain of unspecified controllers to the stable range. The proposed compensation scheme not only ensures that the feedback loop system remains stable, but also provides a simple and effective mechanism for preventing the users from inadvertently setting control gains which degrade the positioning performance of the system. The simulation results confirm the ability of the gain limit compensation scheme to suppress the effects of limit cycles and therefore demonstrate its feasibility for practical applications.