Adaptive Fast Terminal Sliding Mode Control for Automatic Load Alleviation Problem of Refueling Boom Against Disturbances

The refueling boom is widely adopted in recent years because of its advantages in autonomous aerial refueling. During the refueling docking process, the contact between the refueling boom and the refueling receptacle of the receiver UAV may generate an excessive radial force which will cause the refueling boom bent or even damaged. To solve this problem, an automatic unloading system of the refueling boom is designed in this paper. Firstly, the attitude kinematic model of the refueling boom and the loading dynamic model are established, meanwhile the disturbance observer is designed based on sliding mode theory to estimate the exogenous disturbance. Then, the adaptive fast terminal sliding mode control method is adopted to control the attitude of the refueling boom, and the traditional PID control method is further used to achieve the automatic unloading. Finally, numerical simulation results validate the efficacy of the proposed control system.