Robust FOPID controller design by GWO for position tracking of an EHA System

Abstract

Hydraulic positioning systems are widely used in the areas of transportation, earth moving equipment, aircraft, and industry machinery with heavy duty applications. In these systems, nonlinear friction as a typical disturbance, is difficult to model and will influence the system performance. In this paper, we investigate the robust fractional-order PID (FOPID) control for position tracking of a fluid power ElectroHydraulic Actuator (EHA) system which is one type of hydraulic positioning systems. Firstly, the EHA model with friction force uncertainty is built. Then, the FOPID controller which is tuned by the grey wolf optimizer (GWO) is proposed. In the goal function for GWO, we take the uncertainty limits of friction force into consideration. The FOPID parameters are obtained by minimizing the goal function. The effectiveness of the proposed control approach is validated by simulation results in Matlab.