An Autonomous Aerial Refueling Controllable Drogue With Adjustable Strut Angle: Control and Test

Addressing the issues of low docking efficiency and high error rate in autonomous aerial refueling missions, an autonomous control scheme for controllable drogue, which utilizes a strategy of adjustable strut angles, is proposed. First, based on the dynamic model of the hose-drogue system, an actuator scheme of controllable drogue is designed, which utilizes the adjustable strut angles to modulate the shape of the canopy, thereby generating the control forces. Then the aerodynamic model of the drogue is developed, with strut angles serving as the primary control variable. Based on this, a type-II fuzzy logic controller with a novel form of dynamic footprints of uncertainty is proposed, considering the inaccuracy of aerodynamic parameters and time-varying disturbances. Simulation results demonstrate the effectiveness of the controller. Finally, wind field tests were conducted, showing that the swing amplitude of the drogue can be significantly reduced, and the drogue can track the desired instructions to achieve autonomous maneuvering.