Power-Considered Fault-Tolerant Control for Nonlinear Systems With Nonfragile Prescribed Performance

This paper proposes a novel fault-tolerant control scheme that not only addresses traditional gain and bias faults but also considers their impact on actuator power. Specifically, the power index of the faulty input is no longer 1; instead, it is an odd integer greater than 1. Moreover, a novel dynamic boundary relaxation technique (DBRT) is proposed to address the fragility issue in prescribed performance control in the presence of actuator faults. The DBRT continuously monitors and evaluates the proximity between the tracking error and the prescribed performance boundary. It selectively relaxes only a single boundary when the tracking error approaches critical thresholds, effectively preventing singularity issues while minimizing the performance degradation caused by the relaxation. In addition, the prescribed performance function is redesigned to enhance its performance characteristics, including the elimination of the initial feasibility condition, the capability to specify settling time, and the reduction of both transient overshoot and steady-state error. The effectiveness of the scheme is validated through simulation results.