Leader-Follower Formation Control via Fixed-Time Distributed Observer Over Directed Topology: Theories and Applications

The consensus control problem under a leader-follower formation scenario is investigated in this paper, where the interactive link is considered as directed topology. A fixed-time distributed observer (FDO) is proposed to estimate the states of the leader node, whose states are supposed to be accessible for only partial followers. Furthermore, a weighted consensus protocol (WCP) is deployed on unmanned aerial vehicles (UAV) to attain formation tracking. The fixed-time convergence of FDO is proved through Lyapunov theories. A comparative simulation is conducted with FDO against a typical linear observer and WCP against a conventional consensus protocol. The results depict that the faster convergence speed and lower formation tracking error can be reached by FDO and WCP. An outdoor experiment with an unmanned ground vehicle (UGV) as leader and three quadrotor UAVs as followers is performed to enhance the application of the proposed approach.