Consensus of nonlinear multi-agent systems with exogenous disturbances

Most existing research concerning the consensus problem of multi-agent systems has been focused on linear first-order or two-order systems without disturbances. However, in practice, most multi-agent systems are complicated nonlinear system subjected to disturbances. In this paper, the coordinated tracking problem for nonlinear undirected multi-agent systems with exogenous disturbances is studied in the framework of consensus theory. The exogenous disturbances generated by both linear exosystems and nonlinear exosystems are considered. Disturbance observers are developed to estimate the disturbances generated by the linear exogenous systems. The Lyapunov stability theorem is used to prove the asymptotical consensus of the systems. The dynamic gain technique is used to construct the disturbance observer for the disturbance generated by a nonlinear exosystem. Based on the adaptive disturbance observer, a consensus protocol is proposed for the nonlinear multi-agent system. Finally, the proposed design approaches are verified though simulation examples.