Distributed Robust Output-Constrained Control of Unknown Nonlinear Multiagent Systems Under Switching Topologies

The leader-following problem for the heterogeneous nonlinear multiagent systems under output constraints is investigated in this paper. It is focused on the cases where the underlying communication graph is directed and switching, and each agent is a multi-input multi-output block-triangular system with totally unknown and inherently nonlinear dynamics. They render the existing distributed control solutions infeasible. To surmount this challenge, a novel distributed mixed control strategy, composed of a group of robust decoupling constrained controllers and a set of PI-type gain adaption-based controllers, is developed in this paper. It ensures that the outputs of each follower evolve inside the prescribed constraint bands and track the leader outputs with the tunable settling time and accuracy, despite the topology switching. Moreover, it exhibits a prominent simplicity, in spite of the severe model uncertainties, without parameter identification, function approximation, disturbance estimation, or derivative calculation or estimation. The theoretical findings are illustrated by a comparative simulation on a team of planar mobile robots.