Robust Control of Hydraulic Actuator Using Back-Stepping Sliding Mode Controller

To develop an unmanned automatic excavator system the control performance of hydraulic actuators should be guaranteed. However, hydraulic actuators with single rod cylinder have inherently severe nonlinearities that significantly affect to the command following performance of end-effect. PID control system widely used in industries is not proper to compensate the nonlinearities and it is difficult to cancel the unexpected disturbance. In this paper, the robust control scheme to compensate an nonlinearity of hydraulic actuator and cancel an unexpected disturbance is proposed. The proposed control system is designed based on back-stepping controller with sliding model control system. To design the control system, the dynamics of hydraulic actuators is induced and the proposed controller is designed based on the dynamics. In order to evaluate the performance of proposed control system, pressure tracking control system is established and evaluated through experiments.