An Improved Digital PID Algorithm for Angle Position Electric-hydraulic Servo System

PID control algorithm is widely used in servo control system. Because of the non-symmetrical structure of the hydraulic cylinders in the angle position electric-hydraulic servo system of plant converter, the conventional PID control has low control precision and bad flexibility. To solve the problem, an improved digital PID control algorithm with variable sampling periods is proposed. Based on the analysis of the system control principle, the system transfer function is built, and the system response curves are simulated with Matlab. The result indicates that the improved digital PID algorithm with variable sampling periods can reduce the response time, and decrease the overshoot of the system at the same time. In the application, it is proved with the improved digital PID control algorithm, the overshoot, the rise time and the settling time meet the requirements for the angle position control system.