A Formation Maintenance Method of UAV Swarm under Wind Disturbances

Abstract

Formation maintenance control is one of the important methods to maintain the flight stability of multiple UAVs, and the inevitable wind disturbances during formation flight make many existing methods difficult to implement. In this paper, we study the formation maintenance problem when multiple UAVs fly according to the preset trajectory under wind disturbances, and propose a novel decentralized formation control method. A synchronized trajectory generation method that can resist wind disturbances is designed in this paper. The method generates a real-time formation trajectory for each UAV, estimates the time for local aircraft to complete this trajectory after eliminating errors caused by wind, and obtains the time to reach the next waypoint together through inter-aircraft communication. To satisfy the time constraint of the formation trajectory, the trajectory tracker of each UAV generates a virtual point for the local aircraft. A kinematic relationship is established for the UAV to track its virtual point, and a PD velocity controller with wind compensation is designed to enable the UAV to accurately track its virtual point location. We used hardware-in-the-loop simulations to demonstrate the effectiveness of the formation maintenance method in a variety of wind speeds. Subsequently, a field flight test of triangular formation was conducted using 6 miniature fixed-wing UAVs, and the designed formation method can reduce the formation error to about 3m under 6m/s wind speed disturbance.