Fault-tolerant control of multi-agent systems using a Fourier series observer under DoS attacks and periodic intermittent faults

This paper presents an observer design method based on Fourier decomposition and rotational exosystem reconstruction to address periodic intermittent faults that are challenging to handle in existing studies. The research focuses on the fault-tolerant control (FTC) of multi-agent systems (MAS) subject to physical-layer periodic intermittent faults and network-layer Denial-of-Service (DoS) attacks. First, considering the prevalence of periodic faults and the non-differentiability of certain fault signals at switching instants due to instantaneous level transitions, a Fourier observer based on a rotational exosystem model is designed to estimate actuator faults and system states. Second, a FTC protocol integrating an event-triggered mechanism and an open-loop estimator is developed to mitigate the impact of DoS attacks, with further analysis conducted on the attack frequency and duration. Finally, the feasibility of the proposed observer and FTC scheme is validated through a simulation case study.