Cooperative semi-global robust output regulation for nonlinear lower triangular uncertain multi-agent systems

In this paper, the cooperative semi-global robust output regulation problem for the nonlinear lower triangular uncertain multi-agent systems with nonidentical relative degrees is studied. We first introduce a type of distributed internal model to convert the cooperative semi-global robust output regulation problem into the cooperative semi-global robust stabilization problem of its associated augmented system. We then solve this stabilization problem by developing the block semi-global backstepping control technique under some standard assumptions.