Disturbance rejection control for single-rod electro-hydraulic servo system based on dual-extended-state-observer

Uncertainties including matched and unmatched disturbances are the obstacles of developing advanced controllers for electro-hydraulic servo systems. This article presents a dual extended state observer (ESO) with full state to estimate the matched and unmatched disturbances and a robust controller to compensate them. Firstly, the nonlinear mathematical model of the considered single-rod hydraulic system is built. Then, the proposed controller is synthesized based on the backstepping design procedure. The closed-loop system stability analysis indicates that the proposed robust controller achieves guaranteed transient and steady-state tracking performance. Comparative simulation results are obtained to verify the effectiveness of the proposed control strategy.