Active Disturbance Rejection Time-Varying Formation Tracking for Unmanned Aerial Vehicles

Time-varying formation tracking problem for unmanned aerial vehicle (UAV) swarm systems subject to unknown nonlinear dynamics, external disturbances, and switching topologies is studied. The states of the following UAV s are required to form a predefined time-varying formation while tracking the state of the leading UAV. For each following UAV, the unknown nonlinear dynamics and external disturbance are regarded as an extended state of the UAV, and then an extended state observer (ESO) is correspondingly designed. Based on the output of the ESO, a novel time-varying formation tracking protocol is proposed. Rigorous theoretical analysis is given to show that, with the application of the proposed protocol, the ESO estimation error and the time-varying formation tracking error can be made arbitrarily small. A numerical simulation demonstrates the effectiveness of the proposed approach.