Hose-Drum-Unit Modeling and Control for Probe-and-Drogue Autonomous Aerial Refueling

Probe-and-drogue aerial refueling has been widely adopted because of its flexibility, but the drogue is susceptible to wind disturbances, especially the receiver forebody bow wave disturbance and the excessive contact on the drogue. The docking process must be accurate, and a submeter error may result in failure. Thus, it is important for the docking task to understand the dynamics of the drogue under wind disturbances and improve safety after excessive contact happens. In this article, based on the previous work on drogue dynamic modeling, an improved integrated model is proposed by adding the hose-drum unit to describe the behavior of the drogue under wind disturbances more accurately. For the convenience of docking controller design of the receiver aircraft, the simplified drogue dynamic model with the hose-drum unit is obtained through system identification. Finally, to avoid the hose whipping phenomenon after excessive contact on the drogue, a control method is proposed to monitor the state of the hose and control the hose length to stabilize the drogue movement. Simulations and comparisons indicate that the motion of the drogue generated by the proposed modeling method is in good agreement with the real experimental results, and the proposed control method can significantly reduce the effect of the hose whipping phenomenon and improve the safety of probe-and-drogue aerial refueling systems.