Feedback linearized sliding mode control of rotating servo joints

YANG Yu-cheng, LIANG Quan
(College of Mechanical Engineering, Shenyang University of Technology, Shenyang 110870, China)

Abstract: In order to improve the control precision and robustness of the electrohydraulic servo system, reduce the influence of nonlinear and uncertain factors, a controller based on the feedback linearization theory of sliding mode variable structure control was proposed. Through the establishment of the nonlinear model of servo system, the nonlinear model was linearized by using the feedback linearization theory. The controller was designed for the improved system model by combining the sliding mode variable structure control principle. At the same time, the controller based on the fuzzy adaptive PID theory was designed as the control model. Through MATLAB/Simulink simulation, the tracking characteristics and stability of the servo system driven by two kinds of controllers were observed under the condition of no disturbance, time-varying load disturbance and oil pressure fluctuation disturbance. The simulation results show that the servo system based on the feedback linearization sliding mode controller has smaller tracking error, stronger antiinterference ability and effectively improves the robustness of the system compared with the servo system under the fuzzy adaptive PID control.

Key words: rotating servo joint; swinging cylinder; feedback linearization; sliding mode variable structure control; fuzzy adaptive PID control