Cooperative Tracking Control for High-Order Multi-agent Systems Based on Reduced-Order Observer

Focuses on distributed tracking control of leader–follower multi-agent systems with directed communication topologies. The directed communication graph needs to contain a spanning tree. It is supposed that the leader has different internal dynamics with the followers, and each agent cannot measure the states’ information of itself and its neighbors directly. Therefore, a reduced-order observer is designed for the first time for the multi-agent system which contains the external disturbance using an appropriate transformation, and the state information of the agents can be divided into the measurable and unmeasurable part. Then, distributed observer-based consensus protocols are proposed such that all the outputs of the followers reach the same trajectory with the leader’s output, based on the relative outputs of neighboring agents. A multistep algorithm is presented to construct the observer-based protocols. In light of the discrete-time algebraic Riccati equation and internal model principle, output synchronization problem is completed. The result is also extended to the continuous-time multi-agent systems.