Attack Analysis and Resilient Control Design for Discrete-time Distributed Multi-agent Systems

This work presents a rigorous analysis of the adverse effects of cyber-physical attacks on discrete-time distributed multi-agent systems, and propose a mitigation approach for attacks on sensors and actuators. First, we show how an attack on a compromised agent can propagate and affect intact agents that are reachable from it. This is, an attack on a single node snowballs into a network-wide attack and can even destabilize the entire system. Moreover, we show that the attacker can bypass the robust H∞ control protocol and make it entirely ineffective in attenuating the effect of the adversarial input on the system performance. Finally, to overcome the adversarial effects of attacks on sensors and actuators, a distributed adaptive attack compensator is designed based on a virtual estimator. The adaptive attack compensator is augmented with the controller to achieve resilient control. The developed controller achieves secure invulnerable consensus in presence of the attacks. This controller provides remarkable benefits over a class of the existing resilient controller, by making no restriction on the number of agents or agents neighbors under the effect of adversarial input, despite it redeems compromised agent from the effect of the attack. Effectiveness of proposed controller and analysis is validated through simulations.