Multi-degree-of-freedom reliable docking control for probe-and-drogue autonomous aerial refueling

In probe-and-drogue refueling (PDR), it is challenging for the probe to dock with the drogue. This is due to the nonlinearity and various disturbances of the PDR system, which affect both precision and safety. This study fully considers these characteristics, focusing on achieving high-precision tracking and strong robustness against disturbances. To this end, a multi-degree-of-freedom reliable docking control method for PDR based on additive state decomposition (ASD) is proposed. The PDR docking system is initially decomposed into three subsystems of the same order using the ASD approach. Subsequently, three separate controllers are designed for these subsystems: a lyapunov-based controller, a terminal iterative learning controller, and an active disturbance rejection controller. Finally, the three individual controllers are integrated to form a comprehensive controller for the PDR docking system. By constructing a PDR docking simulation platform, it is verified that the proposed method can effectively handle complex disturbances and nonlinearities in the PDR docking system, achieving high-precision docking control. Furthermore, simulation experiments show that the control performance of the proposed docking controller is superior to that of the traditional terminal iterative learning docking controller.