Adaptive Fuzzy Fractional-Order Nonsingular Terminal Sliding Mode Control for a Class of Second-Order Nonlinear Systems

This paper investigates a novel adaptive fuzzy fractional-order nonsingular terminal sliding mode controller (AFFO-NTSMC) for second-order nonlinear dynamic systems. The technique of fractional calculus and nonsingular terminal sliding mode control (NTSMC) are combined to establish fractional-order NTSMC (FO-NTSMC), in which a new fractional-order (FO) nonsingular terminal sliding mode (NTSM) surface is proposed. Then, a corresponding controller is designed to provide robustness, high performance control, finite time convergence in the presence of uncertainties and external disturbances. Furthermore, a fuzzy system with online adaptive learning algorithm is derived to eliminate the chattering phenomenon in conventional sliding mode control (SMC). The stability of the closed-loop system is rigorously proven. Numerical simulation results are presented to demonstrate the effectiveness of the proposed control method.