Depth Control of an Electro-Hydraulic Servo System Based on Fractional Order PID

Electro-hydraulic servo systems (EHSS) are widely used in many industrial applications, and to determine the control strategies to exhibit high robustness and high precision remains the focus of attention. In order to improve the control performance of EHSS, a novel control method, based on fractional PID (FPID) controller, is proposed and designed for the EHSS. The transfer function of EHSS is constructed using first-principle method. The feasibility and availability of the proposed controller are examined by numerical simulation. The control performances of fractional FPID are well assessed based on performance indexes, including response time, tracking accuracy and robustness. The results of the simulation verify that FPID controller is of excellent control performance, and is suitable for the control of EHSS.