Abstract: Electro-hydraulic positioning servo system is a typical nonlinear system, and usually suffersuncertain external disturbances which make the conventional controller fail to meet the high performance requirements. A compound controller based on the dynamic inverse model of system is proposed, which includes a feed-forward controller and a robust controller to improve system control accuracy and robustness respectively. The rules of robust controller are presented and online parameter estimation is given for the compound controller to adapt the system nonlinear characteristics. A case study is presented, and experimental results show that the system nonlinear parameters are estimated accurately and the proposed compound control can handle the external disturbances effectively and upgrade the tracking performance of the hydraulic system.

Key words: Robust control, Adaptive control, Dynamic inverse model, Electro-hydraulic positioning servo system