Multiple sliding mode robust adaptive control of an electro-hydraulic servo system

A multiple sliding mode robust adaptive control strategy is proposed for a class of higher-order nonlinear systems with mismatched uncertain parameters and external load.Recursive technique is used to simplify the control problem of higher-order system.A robust adaptation scheme was used to reduce the tracking error resulted from system uncertainties.First,the recursive technique and state feedback precise linearization scheme is used to obtain the design method of multiple sliding mode controller of a given system.Next,the system-parameter-update law and robust adaptive controller of an uncertain system are presented based on Lyapunov scheme.The proposed method is applied to a position tracking control of electro-hydraulic servo system.The simulation shows that the control approach has good robustness and improves position tracking accuracy considerably.