Tracking control of electro-hydraulic position servo system with uncertainty

Traditional backstepping algorithm requires repeated differentiations for the modelling nonlinearities, and this increases the complexity due to the "explosion of terms" that makes many methods difficult to implement in practice. This paper proposed a novel adaptive robust backstepping tracking control scheme for electro-hydraulic position servo system with constant parameter uncertainties and external disturbances based on the dynamic surface control method. This method combines the robust adaptive backstepping design step with first order low-pass filters, and can be applied without differentiating any model nonlinearities. The proposed adaptive robust controller guarantees the asymptotical semi-global stability of closed-loop system, such that the system output can track well the given desired trajectory. In addition, the final tracking accuracy could be adjusted via certain controller parameters. In order to verify the performance of the deduced controller, numerical simulations are presented. The simulation results show that the proposed controller can obtain the prescribed output tracking transient performance, and owns robustness for the system uncertainties.