Robust flight mode transition control for tail-sitter formation flying with communication delays

In this article, the formation control problem is investigated for a team of unmanned tail-sitters subject to communication delays. A robust distributed and continuous formation control scheme is developed to achieve the desired aggressive time-varying formation flying in flight mode transitions between forward and vertical flights. The proposed control method consists of a translational controller and a rotational controller for each individual tail-sitter to govern the position and attitude motions, respectively. It is proven that the formation system stability can be guaranteed in the presence of communication delays and multiple uncertainties. Simulation results are presented for a team of tail-sitters to illustrate the advantages of the proposed formation flight control algorithm.