Finite-time Prescribed Performance Fault-tolerant Control for a Class of Nonlinear System Using Super-twisting Disturbance Observer

To improve the performance of a class of nonlinear system with actuator fault and external disturbance, a fault-tolerant control method with finite-time prescribed performance is proposed based on the super-twisting disturbance observer in this paper. First, the actuator bias fault and external disturbance of the system are regarded as a lumped disturbance, and it is estimated by the designed super-twisting disturbance observer in finite time. Second, a finite-time prescribed performance fault-tolerant controller under full state constraints is designed by combining the backstepping method, the modified barrier Lyapunov function (MBLF) method and the improved prescribed performance function (IPPF) method. Moreover, the “explosion of complexity” problem in the controller design is solved by the command filters with error compensation. Theoretical analysis shows that the closed-loop system can converge to the neighborhood near the equilibrium point in finite time, and all states are always within the constraint boundaries. Finally, the effectiveness and feasibility of the proposed method are verified by the comparisons of simulations and experiments based on a permanent magnet synchronous motor (PMSM) position system.