Stable PID Control Strategy to Remove Limit Cycle Due to Stribeck Friction on DC Servo Motor

摘要

DC servo motor, in conjunction with PID controller, is widely used for position control in various automation fields. However, the presence of Stribeck friction makes the system prone to experience limit cycle oscillation which can reduce control accuracy. In this research, a stable PID strategy', free from limit cycle oscillation, has been investigated. The investigation has been governed by Bendixson-Dullac criterion and circle stability criterion. Based on the analysis, a minimum value of K_d has been proposed to remedy the limit cycle oscillation. In addition, a maximum value of K_t/K_p has also been suggested to guarantee system stability. The analysis has nullified the notion that only PD controller can remove limit cycle oscillation.