Composite nonlinear feedback control for cooperative output regulation of linear multi-agent systems by a distributed dynamic compensator

This paper investigates the cooperative output regulation problem of linear multi-agent systems with a linear exogenous system (exo-system). The network topology is described by a directed graph which contains a directed spanning tree with the exo-system as the root. Aiming at improving the transient performance of the multi-agent systems, a dynamic control law is developed by the composite nonlinear feedback (CNF) control technique. In particular, a distributed dynamic compensator independent of the interaction on the compensator states of agents among the network, is adopted. The solvability condition for the cooperative output regulation problem is obtained using the small-gain theory, which will not be destroyed by adding the nonlinear feedback part of the CNF control law. It is also shown that in the case with the exo-system not diverging exponentially, the small-gain condition can be guaranteed using the low-gain design. Finally, simulation results illustrate that the proposed CNF control law improves the transient performance for the cooperative output regulation of linear multi-agent systems.