Terminal constraint guidance and predefined-time event-triggered consensus control for multi-UAV aerial rendezvous

Aiming to realize the aerial rendezvous of multi-unmanned aerial vehicles (UAVs) with a carrier, this work proposes a rendezvous guidance and formation control (RGFC) scheme for UAVs. First, according to three-dimensional relative kinematics between the leader in UAVs and the aerial rendezvous point (ARP) behind the carrier, a predefined-time sliding-mode rendezvous guidance method is designed under terminal line-of-sight (LOS) angle and velocity constraints. Then, a predefined-time event-triggered consensus (PTETC) control method for the followers in UAVs is proposed to realize multi-UAV formation control with lower communication consumption. By applying fundamental filtering techniques to the available system states and invariant manifolds, an unknown system dynamics estimator (USDE) is designed to estimate the unknown disturbances. On this basis, a USDE-based UAV backstepping control structure is developed for UAVs to track guidance commands within a predefined time. Furthermore, the stability of the closed-loop system is proved by using a Lyapunov function, and Zeno behavior under PTETC is excluded. Finally, numerical simulations validate the effectiveness of the proposed RGFC scheme.