A comparison study of two disturbance rejection control strategies for hydraulic position servo systems

In hydraulic position servo systems, the parametric uncertainties, the inherent nonlinear characters of hydraulic system and the large variations of payload affect the tracking precision and robust performance. A disturbance observer based control scheme and an integral extended state observer based nonlinear control scheme called active disturbance rejection control are proposed in this paper. A comparison study of these two disturbance rejection control strategies for hydraulic position servo systems has been undertaken. Simulation and experimental results show that the active disturbance rejection control is much superior in dealing with system dynamic uncertainties and disturbances.