Strategic Topology Switching for Security-Part I: Consensus & Switching Times

TL;DR

This paper proposes a decentralized topology-switching strategy for second-order multi-agent systems that ensures consensus in normal operation and enhances detection of stealthy attacks, using dwell time conditions and stable switched system theory.

Contribution

It introduces a novel dwell time-based topology-switching algorithm that guarantees consensus without velocity measurements and is robust against zero-dynamics attacks.

Findings

The proposed algorithm guarantees consensus under specified dwell time conditions.

It achieves consensus using only relative position measurements.

Numerical simulations validate the effectiveness of the strategy.

Abstract

In this two-part paper, we consider strategic topology switching for the second-order multi-agent systems under a special class of stealthy attacks, namely the "zero-dynamics" attack (ZDA). The main mathematical tool proposed here is to strategically switch the network topology to detect a possible ZDA. However, it is not clear a priori that such a switching strategy still yields consensus in this switched system, in the normal (un-attacked) operation mode. In Part I, we propose a strategy on the switching times that enables the topology-switching algorithm proposed in Part II to reach the second-order consensus in the absence of a ZDA. Utilizing the theory of stable switched linear systems with unstable subsystems, we characterize sufficient conditions for the dwell time of topology-switching signal to reach consensus. Building on this characterization, we then propose a decentralized time-dependent topology-switching algorithm. The proposed algorithm, used in conjunction with a simplified control protocol, achieves consensus while providing substantial advantages over other control approaches: it relies only on the relative position measurements (without any requirement for velocity measurements); and it does not impose any constraint on the magnitudes of coupling weights. We finally demonstrate our theoretical findings via the numerical simulation results.