Adaptive Control for UAV Close Formation Flight against Disturbances

In fixed-wing UAV close formation flight adopting the leader-follower configuration, the follower dynamics is affected by the leader-induced trailing vortex effect. This paper considers the trailing vortex effect as external disturbances, and proposes an adaptive control scheme for the follower in order to counteract the trailing vortex effect and achieve accurate formation stabilization control in the horizontal plane. Equations of the relative motion between the leader and the follower considering the trailing vortex effect are derived. Then, an adaptive control law for the follower is designed based on the relative motion model, and adaptation laws are proposed to estimate the trailing vortex disturbances. It is proved via Lyapunov theory that both the lateral and the forward distance errors of the relative motion converge to zero. The effectiveness and robustness of the proposed control scheme are verified through numerical simulations under trailing vortex disturbances.