Resilient Output Formation-Tracking of Heterogeneous Multi-Agent Systems Against Composite Attacks: A Fully-Distributed Event-Triggered Framework

This study investigates the problem of designing countermeasures for resilient output time-varying formation-tracking of multi-agent systems (MASs) in a composite hazardous scenario consisting of various kinds of attacks, such as actuation attacks and denial-of-service (DoS) attacks. Combined with the digital twins concept, the above problem is decoupled into a DoS attack defense scheme on the Digital Twins Layer (DTL) and an actuation attack defense scheme on the Cyber-Physical Layer (CPL) by introducing a DTL with higher security and privacy. On the DTL, a novel Zeno-free event-triggered protocol with sampling state information, equipped with the backup topology countermeasure, is used to suppress the threat of DoS attacks. Note that the resilient protocol against DoS attacks is fully-distributed, which does not need prior knowledge of network algebraic connectivity and thus possesses sufficient scalability to large-scale networks. Moreover, the event-triggered mechanism can completely avoid Zeno phenomena by introducing a strict lower bound for the time interval between cascading triggered events. On the CPL, this study introduces a decentralized, adaptive, and resilient control strategy to address actuation attacks exhibiting exponentially unbounded destructiveness. It is proven that all followers can reach uniformly ultimately bounded convergence by the proposed two-layered control protocols. The effectiveness and resilience of the proposed algorithm are validated through a numerical simulation example.