Continuous nonsingular terminal sliding mode control with anti-windup compensation

The standard application of nonsingular terminal sliding mode (NTSM) control is strictly limited to n-order (n≥2) systems and suffers from chattering problem. This paper proposes a continuous NTSM control for extended first order systems to obtain the global finite-time convergence and free-chattering simultaneously. Firstly, utilizing the concept of relative degree, a power-fractional NTSM manifold is designed. Then, based on Lyapunov stability theorem, a switching control law is designed to act on the derivative of NTSM variable, so that the real control is smoothed by integral action. Meanwhile, since the integral term is incompatible with input saturation in real systems, anti-windup compensation should be made accordingly. Taking permanent magnet synchronous motor as an example, simulation results are presented to validate the proposed method.