Sliding mode control with switching-gain adaptation based-disturbance observer applied to an electro-hydraulic actuator system

This paper presents a new robust control scheme using sliding mode control associated with disturbance observer enhanced by varying boundary layers technique. Switching-gain of the sliding mode is adaptable on the estimated disturbance. The scheme is developed to guarantee tracking accuracy of an electro-hydraulic actuator system with robust and smooth control actions in the existence of uncertainties and the changes of external load disturbance. Robustness and smoothness of the control actions is assured if the switching gain of the control law is greater and adaptable on the bounds of the uncertainties and the disturbance. Moreover, the smoothness of the control input is enhanced by varying boundary layers technique based on the estimated disturbance. The capability of the proposed controller is validated through simulation. The simulation results indicate that the proposed scheme ensures the tracking performance with smooth control actions in different levels of the external load disturbance. This scheme offers a significant efficiency of energy in the control of EIlA systems.