Semi-global weighted output average tracking of heterogeneous multi-agent systems in the presence of actuator saturation and external disturbances

This article studies the problem of semi-global weighted output average tracking of a heterogeneous multi-agent system in the presence of actuator saturation and external disturbances. The multi-agent system contains a group of leader agents and a group of follower agents. Both the dynamics of leader agents and the dynamics of follower agents are allowed to be heterogeneous. Applying the classical output regulation theory and the low gain feedback design technique, we construct for each follower agent a state feedback control protocol and an output feedback control protocol, both parameterized in a scalar parameter. In both the state feedback case and the output feedback case, we construct distributed leader state observers for each follower agent that estimate the states of the leader agents. In the case of output feedback, we also construct for each follower agent state observer that estimates its own state. It is shown that, under these control protocols with a sufficiently small value of the parameter, each follower agent can track the weighted average of the outputs of the leader agents from an arbitrarily large bounded set of initial conditions and in the presence of actuator saturation and external disturbances if there exist directed paths from each leader agent to all the follower agents. Simulation results are given to illustrate the theoretical results.