This paper proposes an Emergency Battery Service (EBS) for drones in which an EBS drone flies to a drone in the field with a depleted battery and transfers a fresh battery to the exhausted drone. The authors present a unique battery transfer mechanism and drone localization that uses the Cross Marker Position (CMP) method. The main challenges include a stable and balanced transfer that precisely localizes the receiver drone. The proposed EBS drone mitigates the effects of downwash due to the vertical proximity between the drones by implementing diagonal alignment with the receiver, reducing the distance to 0.5 m between the two drones. CFD analysis shows that diagonal instead of perpendicular alignment minimizes turbulence, and the authors verify the actual system for change in output airflow and thrust measurements. The CMP marker-based localization method enables position lock for the EBS drone with up to 0.9 cm accuracy. The performance of the transfer mechanism is validated experimentally by successful mid-air transfer in 5 seconds, where the EBS drone is within 0.5 m vertical distance from the receiver drone, wherein 4m/s turbulence does not affect the transfer process.

翻译：本文提出了一种面向无人机的紧急电池服务（EBS），其中EBS无人机飞至现场电量耗尽的无人机处，并将满电电池转移至缺电无人机。作者提出了一种独特的电池转移机制，以及采用十字标记位置（CMP）方法的无人机定位方案。主要挑战包括实现稳定且平衡的转移，以精确定位接收无人机。所提出的EBS无人机通过采用与接收无人机的对角线对齐，将两架无人机之间的距离缩短至0.5米，从而减轻了因垂直接近导致的下洗气流影响。计算流体动力学（CFD）分析表明，对角线对齐相较于垂直对齐能最大限度减少湍流，作者通过实际系统验证了输出气流与推力测量的变化。基于CMP标记的定位方法可实现EBS无人机位置锁定，精度高达0.9厘米。实验验证了转移机制的性能：在5秒内成功完成空中转移，此时EBS无人机与接收无人机的垂直距离为0.5米，且4米/秒的湍流不会影响转移过程。