Adaptive Backstepping Nonsingular Terminal Sliding Mode Control of Servo System Based on New Sliding Mode and Reaching Law

Abstract

Aiming at the problem that the control accuracy of permanent magnet synchronous motor (PMSM) servo system is easily affected by parameter uncertainty, an adaptive backstepping nonlinear nonsingular terminal sliding mode control (ABNNTSMC) method is proposed in this paper. Based on the existing fast nonsingular terminal sliding mode, a new piecewise nonlinear nonsingular terminal sliding mode is proposed to improve the convergence speed and ensure the steady-state accuracy. At the same time, a new reaching law with attenuation term is proposed to reduce the vibration gradually. Finally, the adaptive law is used to estimate the moment of inertia and viscous friction coefficient of the system to improve the robustness of the system. Simulation results show that ABNNTSMC has higher steady-state accuracy and smaller vibration compared with several existing results.