Multiple UAV distributed close formation control based on in-flight leadership hierarchies of pigeon flocks

Owing to the similarity between bird flocks and unmanned aerial vehicle (UAV) swarms among intelligence, autonomy and local interactions, the collective motion mechanisms in bird flocks have reference significance for the design of distributed control algorithms for multiple UAVs. In this paper, a pigeon flocking model is proposed based on the in-flight leadership hierarchy in pigeon flocks. Graph theory is adopted to describe the transformation process from an arbitrary connected topology to the leadership hierarchy required for a line formation. The leader-follower relations are defined as the guidance from leaders to followers on the relative positions. On the basis of the pigeon flocking model, a distributed close formation control method to coordinate multiple UAVs to fly in a line close formation is presented. The simulation results based on the UAV close formation model, modified by the additional nonlinear aerodynamic interactions, are elaborated to show the feasibility and validity of our proposed method.