Integration of Time-Varying threshold-based Fault Detection and Tolerant Control

An integrated fault detection and fault-tolerant control scheme are proposed for uncertain strict-feedback systems with unmeasurable states in this paper. A fault detector, which comprises a residual generator with a prescribed performance and a tight time-varying threshold calculated from the prescribed performance bound, is first designed. After the faults are detected, a fault-tolerant controller is then proposed where the residual generator is regarded as the reference model of the virtual actuator. It is shown that all system states and estimation errors are uniformly bounded before the detection of faults and converge to zero when the proposed fault-tolerant controller is deployed. A simulation example is provided to manifest the effectiveness of the proposed scheme.