Hybrid consensus-based formation control of UAVs

Abstract

In this paper, hybrid consensus based formation control for a team of Unmanned Aerial Vehicles (UAV’s) is considered. A hybrid consensus based formation controller is applied for UAV’s moving at fixed altitudes to drive them to a goal point while maintaining a specified formation. The proposed hybrid automaton consists of two discrete states, each with continuous dynamics: a regulation state and a formation keeping state. The controller in the regulation state uses local state information to achieve its objective while the formation controller utilizes the state and controller information of neighboring UAV’s. Consequently, the UAV’s switch between the control objectives of formation keeping and goal seeking in route to their goal points. The switching behavior creates hybrid dynamics from the interactions between the continuous and discrete states making the stability analysis of the system more complex than considering purely discrete or purely continuous. Therefore, the stability of the hybrid approach is proven by using multiple Lyapunov functions and also considers the switching conditions between the regulation and the formation states. The Lyapunov based approach demonstrates that the formation errors converge to a small bounded region around the origin and the size of the bound can be adjusted by using the switching conditions. Convergence to goal position while in formation is also demonstrated in the same Lyapunov analysis, and simulation results verify the theoretical conjectures.