Time-Varying Formation Tracking Control for Multi-UAV Systems with Directed Graph and Communication Delays

In this paper, we investigate the time-varying formation tracking (TVFT) control problem for multiple unmanned aerial vehicles (multi-UAVs) with directed interaction topology and communication delays. Firstly, each UAV is modeled by the double integrator for the TVFT control problem. Then a consensus based protocol utilizing neighboring relative state information with time-varying delays is constructed. Sufficient conditions for multi-UAV systems with communication delays to achieve TVFT are illustrated and the stability of the proposed control protocol is shown based on Lyapunov-Krasovskii functional approach. Furthermore, we present a multi-UAV system to verify the proposed protocol. The architecture of the multi-UAV system which consists of four quadrotors is introduced. Finally, numerical simulations and flying experiments are presented to illustrate the feasibility and effectiveness of the proposed control protocol.