Formation Control Algorithms for Multi-UAV Systems with Unstable Topologies and Hybrid Delays

Multi-UAV systems rely on the communication network to exchange mission-critical data for their coordination and deployment, while communication delays could cause significant challenges to both tasks. The impact of the delays becomes even more severe if the delay, network structure and formation are all time-varying, a common challenge faced by real-world multiUAV systems. To address this challenge, we consider time-varying delays that exist in multiple channels caused by transmitting information and internal delays that exist in UAVs themselves caused by obtaining and processing their own data. We design an effective distributed formation control protocol for a multiUAV system to achieve time-varying formation; this protocol is particularly useful for dealing with time-varying multi-UAV network topologies as well. We provide rigorous convergence analysis for different scenarios with or without hybrid delays and obtain sufficient conditions for achieving the time-varying formation. Furthermore, we propose an algorithm for quantifying the maximum delay allowed by the system. Based on the designed formation algorithm, a deployment strategy is proposed to coordinate multi-UAV systems in a practical environment. Numerical analysis and UAV hardware experiments are conducted to evaluate the performance of the theoretical results and investigate the feasibility of generated flight trajectories.