Finite-time switching-like sliding mode fault-tolerant control for discrete-time cyber-physical systems under DoS attacks and intermittent faults

In this article, the finite-time sliding mode fault-tolerant control problem is addressed for discrete-time cyber-physical systems with intermittent faults and denial-of-service (DoS) attacks. To model the intermittent nature of faults, two sequences of shifted gate functions are employed to depict the fault appearance and disappearance moments. Considering that DoS attacks can prevent transmission of signals, resulting in measurement data losses over the sensor to observer channel, switching-like observer and sliding mode fault-tolerant controller are presented to accommodate both situations with and without attacks. The designed sliding mode fault-tolerant controller can ensure the finite-time reachability of the sliding surface such that it can enter the quasi-sliding mode domain within finite time from any initial state. Moreover, based on the Lyapunov theory, sufficient criteria are derived to guarantee the finite-time boundedness of the closed-loop systems with intermittent faults and DoS attacks in both the reaching and sliding motion phases. Finally, the effectiveness of the proposed sliding mode fault-tolerant control scheme is verified by a numerical example and a practical example.