On the internal model principle in formation control and in output synchronization of nonlinear systems

The role of internal model principle is investigated in this paper in the context of collective synchronization and formation control problems. In the collective synchronization problem for nonlinear systems, we propose distributed control laws for passive systems which synchronize to the solution of an incrementally passive exosystem. This generalizes the result from linear systems where the existence of an internal model is required for the output synchronization of networked systems. In our second result, a distributed control law that solves a formation control problem for incrementally passive systems is proposed based also on the internal model principle.