Robust output consensus of networked heterogeneous nonlinear systems by distributed output regulation

In this paper, we study the output consensus problem of networked heterogeneous nonlinear systems. In contrast to existing results on similar problems, output consensus of all systems is achieved with some robustness not only to heterogeneous dynamics with uncertainties but also to unreliable network communication in terms of network connectivity and communication delays. In particular, we allow the time-varying network topology and the presence of time-varying communication delays in network, which are among the most challenging issues in cooperative control. To solve the problem, we propose a hierarchical control scheme and design a distributed dynamic output feedback control law by the distributed output regulation approach. The proposed control approach offers great flexibility to incorporate the output regulation approach, the separation principle and the certainty equivalence principle to stability analysis of the closed-loop system, thus setting a stage for systematically studying the robust output consensus problem. By establishing some technical lemmas and resorting to ISS Lyapunov technique, we solve the robust output consensus problem of nonlinear multi-agent systems subject to system uncertainties, jointly connected directed network topologies, and arbitrarily bounded and nonuniform time-varying communication delays.