Optimal and hierarchical formation control for UAV

In this paper, optimal and hierarchical control concepts are investigated for cooperative formation flying of aircrafts. The airplanes are modeled as point mass and represented by double integrators. And all the planes are considered to be in a plane. For demonstration of the concepts, a task of forming a square from arbitrary initial conditions is presented to four airplanes. The final position that each airplane has to reach is unknown to them. The goal for the team is abstracted in the top layer. The system is modeled as a two layer hierarchical system in which the global information comes from the top layer. Following this global information, a square is formed in the bottom layer according to tracking of the top layer setting. Two cases are considered in this paper: the first is the time optimal square forming problem. The other is maintenance and movement of the formation, both are solved in this hierarchical structure. Numerical results from simulating these two cases are presented. From the simulation results, the effectiveness of the hierarchical concept for the UAV class of problems is demonstrated.