Structural controllability of multi-agent systems with absolute protocol under fixed and switching topologies

The paper investigates the structural controllability of leader-follower multi-agent systems under fixed and switching topologies. Three models of agents: double-integrator, high-order integrator and general-linear dynamics are analyzed. Necessary and sufficient graphical conditions are provided for structural controllability based on communication topology of the system. In particular, a linear neighbor-based control protocol is designed for generic linear agents under which structural controllability is proved to be uniquely determined by communication topology structure. The role that leaders play in the structural controllability of multi-agent system is characterized, and a method is developed to realize structural controllability under single leader. The results clearly indicate the role of leaders and the effect of communication topology on structural controllability.