Distributed bearing-based formation maneuver control of fixed-wing UAVs by finite-time orientation estimation

This paper investigates the bearing-based formation maneuver control problem for a group of fixedwing unmanned aerial vehicles. Unlike the existing works that only steer UAV swarm to achieve a fixed geometric pattern, our objective is to enable UAV swarm to maneuver as a group such that the centroid, scale and orientation of the formation can be continuously changed. The underlying graph of UAV swarm is assumed to satisfy a leader-first-follower structure, and the desired formation maneuvering parameters are only accessible to the leader. To address such issue, a cascaded control scheme is proposed. Firstly, we propose a distributed quaternion-based observer for each follower to estimate the desired orientation of the formation in finite time. Secondly, a bearing-based formation control law is developed to achieve the maneuvering formation, in which an adaptive-gain finite-time disturbance observer is synthesized to reject the deformations which vary the bearing constraints. It is demonstrated that the closed-loop formation tracking error converges to zero exponentially. Comparative simulations are preformed to demonstrate the effectiveness of the proposed method.