Nonsingular terminal sliding mode control with compound sliding surface based on ESO

According to the slow convergence and control input chattering phenomenon in traditional nonsingular terminal sliding mode(NTSM) control, a controller design method based on the compound sliding surface and the extended state observer(ESO) is proposed. A staged controller is adopted combined with the compound sliding surface to accelerate the convergence speed. On this basis, the ESO is used for real-time estimation and compensation of system uncertainty, which effectively weakens the chattering caused by un-modeled system dynamics. The finite time convergence properties of the two methods are proved respectively. Simulation results verify the effectiveness of the proposed methods, and show fast convergence and strong robustness of the control system.