Performance recovery-based low-computation adaptive self-triggered fault-tolerant control for nonlinear systems with actuator replacement and unmatched disturbances

In this paper, a low-computation adaptive fault-tolerant control (FTC) scheme is proposed for a class of strict-feedback nonlinear systems with unmatched disturbances. In contrast to existing FTC schemes, a method called delayed actuator replacement is taken into account, that is, the backup actuator cannot be connected to the system immediately after failure detection. In order to restore the tracking error to the prescribed performance within a specified time, a set of shifting functions is established to derive new error variables. In addition, by introducing two novel error transformation functions, the designed low-computation adaptive control method overcomes the complexity explosion problem and simplifies the design process. Furthermore, a self-triggered mechanism is designed to improve the transmission efficiency of the whole system. The validity of our control scheme is demonstrated through a simulation example.