Dynamic modeling and simulation of variable-length hose–drogue aerial refueling systems

This paper describes an improved modeling and simulation analysis of a variable-length reel take-up system for hose retrieval/deployment during aerial refueling. Based on a previously developed finite segment model, full reel acceleration is applied to the first rigid link connected to the towing point. The variation in the length of the hose and its rate of change are distributed evenly across all of the hose segments through a re-discretization technique, and the dynamics of the hose’s motion are regarded as a series of quasi-static processes. First, numerical simulations of the steady-state trailing hose are compared with previous results and flight data. The non-linear dynamics of a variable-length hose–drogue system during aerial refueling are then analyzed under various retrieval/deployment conditions. The results indicate that the finite segment model is prone to inducing chain-link oscillations in the hose dynamics, which are not appropriate for such a flexible body. In two application cases, the non-physical oscillations were well filtered using the proposed method, achieving a simultaneous combination of accuracy, stability, and robustness. Several advantages of the simulated hose dynamics provide a theoretical basis and platform for subsequent research into control strategies for suppressing the hose whipping phenomenon during hook-up.