2004 Volume 17 Issue 1 Pages 26-38
In this paper, we develop two controllers to control simplified dynamic models of three unmanned aerial vehicles (UAVs) in formation. The formation control scheme is constructed in a hybrid system fashion, i.e., switching between two stable systems with state-dependent (collision-detection based) switching logic. Main Formation Controller (MFC) is designed based on Lyapunov direct method and integrator backstepping techniques playing the role of formation hold between two UAVs. Collision Avoidance Controller (CAC) gives benefit to the short range collision avoidance using polar coordinate instead of traditional relative model to capture motions between two UAVs. The proposed collision avoidance control uses the sliding mode control with better choices of sliding surfaces to effectively establish the desired collision avoidance behavior. Fusion of both controllers establishes stability and convergence to the reference formation by means of switching control. The numerical simulation results prove the validity of the proposed control scheme.