Adaptive PID sliding mode controller application to position control of hydraulic system

Abstract

This study proposes a sliding mode controller combined with the direct parameter adjustment method of proportional–integral–derivative (SMCPID) to control a hydraulic cylinder system. A simulation model using a hydraulic cylinder and a damper is set up to verify the results and accuracy of the proposed controller. In the SMCPID controller, a PID controller is used to generate a control signal combined with the sliding plane to stabilize and sustain the sliding mode. Due to the hydraulic system's nonlinear nature, the PID controller's coefficients need to be calculated and adapted according to an adaptive law. The SMCPID controller has been tested and compared with other controllers such as the PID controller, fuzzy controller combined with PID, and fuzzy controller combined with adaptive PID in controlling the position of the cylinder axis for different target paths. Simulation results are performed to verify and analyze the effectiveness of the proposed controller.