Multi-vehicle circular formation flight in an unknown time-varying flow-field

This paper presents a coordination technique for circular formation flight of multiple Unmanned Aerial Vehicles (UAVs) to circle around a ground target when a wind with an unknown velocity and direction is blowing. The guidance law is based on the line-of-sight (LOS) method which has the ability to transfer UAVs to different formation patterns through a single parameter change. An optimal control law is applied to a linear dynamic model employing a linear quadratic regulator (LQR) control technique. A leader-follower coordination model is adopted for encirclement around the ground target. In order to verify the performance of the proposed system, a numerical simulation is demonstrated.