Aerodynamic configuration and control optimization for a novel horizontal-rope shipborne recovery fixed-wing UAV system

Efficient UAV performance and a perfect recovery system are required to achieve the safe and reliable shipborne recovery of fixed-wing UAVs, which is essential for expanding their marine applications. In this study, taking an automatic horizontal-rope shipborne recovery (aHRSR) system as the recovery platform, a joint optimisation method of fixed-wing UAVs combined aerodynamic configuration and control optimisation was investigated. First, the distribution of a dynamic system was adopted to attain aerodynamic optimisation. A wing-mounted double-engine pull (WMDE-PULL) configuration was developed based on the slipstream effect. Compared with the tail-mounted single-engine push (TMSE-PUSH) configuration, the WMDE-PULL configuration could significantly enhance the lift and low-speed characteristics and eliminate the disturbances from the reaction torque of the single-engine propeller. This aerodynamic optimisation method evidently improved the control accuracy of the controller. To offset the comprehensive disturbance under complex conditions at the sea, including the internal disturbance of the additional torque and external disturbance of the wake, the acceleration feedback method was implemented for the inner loop attitude of the original controller. The optimised controller had good robustness and stability. Several experiments were conducted for the recovery of the optimised UAV on the aHRSR system, and a recovery success rate of 100% was achieved. The results show that the joint optimisation method of fixed-wing UAVs is valid and practical, and the recovery scheme of an optimised fixed-wing UAV on an aHRSR system provides practical reference for shipborne recovery.