Strategic Topology Switching for Security-Part II: Detection & Switching Topologies

This two-part paper considers strategic topology switching for the second-order multi-agent system under attack. In Part II, we propose a strategy on switching topologies to reveal zero-dynamics attack. We first study the detectability of zero-dynamics attack for the second-order multi-agent system under switching topology, which has requirements on the switching times and switching topologies. Based on the strategy on switching times proposed in Part I [1] and the strategy on switching topologies proposed here, a decentralized strategic topology-switching algorithm is derived. Its primary advantages are threefold: (i) in achieving consensus in the absence of attacks, the control protocol does not need velocity measurements and the algorithm has no constraint on the magnitude of coupling strength; (ii) in revealing zero-dynamics attack, the algorithm has no constraint on the size of misbehaving-agent set, while it allows the defender or the system operator to have no knowledge of the attack-starting time; (iii) in revealing zero-dynamics attack, if the Laplacian matrix of Xor graph generated by consecutive switching topologies has distinct eigenvalues, only one observed output of position is sufficient. Simulations are provided to verify the effectiveness of the strategic topology-switching algorithm.