Closed electro-hydraulic proportional system based on multiple sliding mode adaptive control

According to the nonlinear closed electrohydraulic proportional system, a multiple sliding mode adaptive control method is proposed. 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. Firstly, 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. Then, 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 speed tracking control of an electrohydraulic proportional system. Simulation results indicate that the control approach is robust and improves tracking accuracy considerably.