SMDO-based backstepping terminal sliding mode control method for hot press hydraulic position servo system

This paper presents an adaptive backstepping terminal sliding mode control scheme combined the sliding mode disturbance observer for hot press hydraulic position servo system with composite disturbance including internal parameter perturbations and external load disturbance. The sliding mode disturbance observer (SMDO) based on adaptive-gain super-twisting (STW) algorithm is introduced to ensure the robustness of the control system with respect to composite disturbance and to improve the control performance. Meanwhile, an adaptive backstepping terminal sliding mode controller based on SMDO is designed by introducing a novel non-singular terminal sliding mode (NTSM). This designed controller can derive the tracking error of the third subsystem to converge to equilibrium point in finite time, thus, a faster convergence rate and higher tracking precision can be obtained, and the control input is smooth and chattering-free. Simulation experiments are performed to illustrate the effectiveness and superiority of the presented control scheme.