Backstepping Control of Electro-Hydraulic System Based on Extended-State-Observer With Plant Dynamics Largely Unknown

In this paper, an output position feedback control of the electro-hydraulic system (EHS) is proposed based on an extended-state-observer (ESO) with backstepping. On the basis of the augmented state model of the EHS, the ESO is designed to handle the unknown load disturbance and uncertain nonlinearity. Then, an observer bandwidth constraint is derived to compromise between the dynamic performance and the maximal load capability of EHS. The effectiveness of the proposed control for the suppression of largely unknown disturbances has been demonstrated by comparative experimental study, which indicates the proposed approach can achieve better dynamic performance on the motion control of two-degree-of-freedom robotic arm.