Distributed Formation Control and Navigation of Fixed-wing UAVs at Constant Altitude

We present a distributed control strategy for a team of fixed-wing Unmanned Aerial Vehicles (UAVs), such that they achieve a desired formation and travel along a desired direction at a constant altitude. We describe the motion of UAVs with the kinematic unicycle model, and impose the constraints that the airspeed and turning rate of UAVs must satisfy some practical bounds. Based on this model, a control strategy is proposed, and local convergence of the team to the desired formation and travel direction is proved. The control direction returned by our strategy is well-suited as a high-level motion planning input to a low-level UAV autopilot, which can compensate for the aerodynamics, wind effects, disturbances, etc., that are not accounted for in the unicycle model. The proposed strategy is fully distributed and can be implemented using relative position measurements acquired by UAVs in their local coordinate frames. Furthermore, UAVs do not need to communicate. Simulations are provided to typify the proposed strategy.