Adaptive Fault-Tolerant Control and Performance Recovery Against Actuator Failures With Deferred Actuator Replacement

In this article, an adaptive fault-tolerant control (FTC) scheme is proposed for a class of uncertain nonlinear systems with actuator failures, in which a backup actuator is available. Different from existing FTC methods applying dynamic redundant actuators, a situation of deferred actuator replacement is firstly taken into account, i.e., the backup one cannot connect to plant right after failure detection. To recover the tracking error into prescribed performance within a specified time, an error transformation is introduced to render tangent barrier Lyapunov functions valid at the replacement instant, by which reconfigurable controller can be designed for the backup actuator. Simulation results on a flight control system are presented to illustrate the effectiveness of the FTC scheme.