Robust Close Formation Flight Control Based on Vector Fields

The utilization of unmanned aerial vehicle (UAV) with fixed wings tight formations in real flight offers a multitude of advantages. However, it is important to recognize that there are numerous and unpredictable disturbances in tight formations, as the vortices generated by the lead airplane affect the aerodynamics of the following airplane in the formation. To make optimal use of tight formations in enhancing the range of the formation, it is essential to design robust controllers to maintain the stability of UAV formation flight. This paper presents the first establishment of a mathematical model of a flight formation’s wake vortex, which is then used to design a nonlinear robust controller for tight formation flight based on vector field theory. The controller employs a vector field method in conjunction with sliding mode control, thereby a fortiori permitting the aforementioned aircraft to accurately track the lead aircraft’s position even in the existence of the lead airplane’s vortex. The stabilization of proposed controller is then demonstrated and verified in mathematical simulations. The results of experiments demonstrate that the proposed controller exhibits excellent close formation accuracy and robustness to tail-vortex perturbations.