ROBUST ACTIVE FAULT-TOLERANT CONTROL FOR A CLASS OF UNCERTAIN NONLINEAR SYSTEMS WITH ACTUATOR FAULTS

For a class of uncertain nonlinear systems with actuator faults, robust active fault-tolerant control is investigated based on the adaptive observer, feedback linearization, and backstepping design theory. Time-varying faults and bounded uncertainty are simultaneously considered in the paper. An, adaptive observer is firstly constructed to estimate the faults and then a backstepping-based active fault-tolerant controller is designed to compensate for the faults. The main theoretical contributions of this work are a new fault updating law which relaxes the assumption. conditions of the fault diagnosis observer and a new recursive control law for tracking the time-varying reference input signal. The asymptotical stability of the closed-loop fault-tolerant control system is proved by Lyapunov theorem. The numerical simulation results demonstrate the application and effectiveness of the proposed scheme.