Formation Control of Multi-UAV Systems with Time and Angle Constraints

This study addresses the formation control problem of multiple fixed-wing unmanned aerial vehicles (UAV) in three dimensions, taking into account assembly time and angle constraints. A novel control strategy is proposed, which divides the system into two modules. The first module, known as the assembly stage, assembles the UAV swarm and creates a fundamental formation from arbitrary initial states. Each UAV is required to reach the designated site while considering the terminal constraints regarding both time and angles. Novel sliding manifolds have been developed, and corresponding control laws are proposed to meet the constraints in the assembly stage. The Lyapunov stability theory is employed to prove that the proposed control laws guarantee a fixed-time stable system. The second module, referred to as the formation-keeping stage, is responsible for precisely maintaining the UAV swarm’s geometric pattern. The study proposes a sliding mode control (SMC) law that uses the traditional proportional navigation guidance (PNG) for followers to trace the relative trajectories of a predetermined central leader in a leader-follower structure. Finally, numerical simulation results are presented to demonstrate the successful implementation of the proposed approach. Compared to the two other methods, our proposed approach not only satisfies the constraints but also exhibits a higher level of distance accuracy. In precise terms, our method achieves a reduction in the average distance error of 73% and 87%, respectively, when compared to the previous two methods.