Continuous Nonsingular Terminal Sliding Mode Control for Hydraulic Manipulator with Time-Delay Estimation

To realize satisfactory trajectory tracking control performance of hydraulic manipulators under strong couplings and large external disturbances, a novel model-free continuous nonsingular terminal sliding mode control method is proposed in this paper. The proposed method mainly has two elements, the time delay estimation (TDE) technique and the continuous nonsingular terminal sliding mode (CNTSM) control algorithm. The former utilizes only the position information of the close-loop control system and then realize the estimation and compensation of the lumped system dynamics, which can effectively reduce the required control gains needed by the latter and improve the system robustness. The latter enjoys the strong robustness of sliding mode (SM) control and combines the NTSM manifold and corresponding reaching law, and then guarantees high performance trajectory tracking control under complex disturbance. The convergence of the closed-loop control system is proved using Lyapunov stability theory, finally simulation was performed to verify the effectiveness and superiorities of the proposed control method over the existing linear SM control method.