Autonomous UAV Mission Cycling: A Mobile Hub Approach for Precise Landings and Continuous Operations in Challenging Environments

Environmental monitoring via UAVs offers unprecedented aerial observation capabilities. However, the limited flight durations of typical multirotors and the demands on human attention in outdoor missions call for more autonomous solutions. Addressing the specific challenges of precise UAV landings-especially amidst wind disturbances, obstacles, and unreliable global localization-we introduce a mobile hub concept. This hub facilitates continuous mission cycling for unmodified off-the-shelf UAVs. Our approach centers on a small landing platform affixed to a robotic arm, adeptly correcting UAV pose errors in windy conditions. Compact enough for installation in an economy car, the system emphasizes two novel strategies. Firstly, external visual tracking of the UAV informs the landing controls for both the drone and the robotic arm. The arm compensates for UAV positioning errors and aligns the platform's attitude with the UAV for stable landings, even on small platforms under windy conditions. Secondly, the robotic arm can transport the UAV inside the hub, perform maintenance tasks like battery replacements, and then facilitate direct relaunches. Importantly, our design places all operational responsibility on the hub, ensuring the UAV remains unaltered. This ensures broad compatibility with standard UAVs, only necessitating an API for attitude setpoints. Experimental results underscore the efficiency of our model, achieving safe landings with minimal errors (≤ 7 cm) in winds up to 5 Beaufort (8.1 m/s). In essence, our mobile hub concept significantly boosts UAV mission availability, allowing for autonomous operations even under challenging conditions.