Distributed adaptive consensus protocols for linear multi-agent systems with directed graphs in the presence of external disturbances

This paper revisits the distributed adaptive consensus protocol in [1] when the agents are subject to external disturbances. To deal with the parameter drift phenomenon associated with the adaptive protocol in [1], we propose a novel distributed adaptive protocol by using the σ modification technique. It is shown that this novel adaptive protocol can guarantee the ultimate boundedness of both the consensus error and the adaptive coupling weights for linear multi-agent systems whose communication graph contains a directed spanning tree with the leader as the root node, and thereby is robust in the presence of external disturbances.