Fault Detection-Based Optimal Performance Recovery Control for Nonlinear Systems via an Actuator Replacing Method

This paper concentrates on a fault detection-based performance recovery control scheme using an actuator replacing method. The main procedure includes: 1) an integral sliding-mode (ISM) based event-triggered nominal controller; 2) a shifting-function-assisted fault detection design; and 3) an event-triggered reconfigurable controller. Unlike existing FTC schemes, no prior fault model is required. Minor actuator faults are directly attenuated via ISM, whereas significant faults are handled by switching to a backup actuator. For both nominal and reconfigurable phases, a modified Hamilton-Jacobi-Bellman (HJB) equation is solved with a single critic neural network, and an experience replay mechanism mitigates the persistence of excitation requirement while reducing computational complexity. A shifting function guarantees that post-replacement reconstructed states re-enter the prescribed performance bound within a finite window, and an actuator-oriented event-triggered strategy lowers update frequency while ensuring single-actuator operation. The effectiveness of the proposed scheme is validated by two simulation examples.