This paper considers the controllability problem for multi-agent systems. In particular, the structural controllability of multi-agent systems with a single leader under switching topologies is investigated. The structural controllability of multi-agent systems is a generalization of the traditional controllability concept for dynamical systems, and purely based on the communication topologies among agents. The main contribution of the paper is a graph-theoretic characterization of the structural controllability for multi-agent systems. It turns out that the multi-agent system with switching topology is structurally controllable if and only if the union graph G of the underlaying communication topologies is connected. Finally, the paper concludes with several illustrative examples and discussions of the results and future work.
Xiaomeng Liu, Hai Lin, Ben M. Chen