Cooperative robust output regulation for nonlinear multi-agent systems with unity relative degree subject to a nonlinear leader

In this paper, we study the cooperative global robust output regulation problem for unity relative degree nonlinear multi-agent systems in normal form with a non- linear leader system. The same problem was studied recently under the assumptions that the leader system is linear and the communication network is undirected. By employing a distributed nonlinear internal model, we will construct a control law that accommodates nonlinear leader systems, and directed communication networks. Our result will be illustrated by an example with the well known Van der Pol osicllator as the leader system.