Decentralized Adaptive Control for Interconnected Cyber-Physical Systems under Coordinated Attacks

This paper introduces a decentralized adaptive control scheme for networks of cyber-physical systems under sensor and coordinated actuator attacks. First, a simplified model, in which each node system is isolated, is studied. A partially adaptive controller with a non-adaptive linear component and an adaptive nonlinear component is proposed: this guarantees bounded system trajectories and asymptotic regulation of the state. Then, the whole network system under coordinated actuator attacks is studied and a decentralized fully adaptive controller is proposed. By jointly placing the fully adaptive controller and the partially adaptive controller, according to the so-called feedback vertex set of the underlying graph, boundedness and convergence properties of the simplified model can be guaranteed for the entire network. Finally, a simulation example for a multi-stage water distribution system is presented. The results show that the proposed controller guarantees robustness of the closed-loop network system against sensor and coordinated actuator attacks and it is capable of restoring the transient performance to that of the attack-free case.