From Hitch to Lift: Autonomous Cable Interlacing by Multi-UAV Teams for Aerial Grasping and Transportation

The use of cables in aerial manipulation offers a lightweight and flexible alternative to rigid grasping mechanisms. However, achieving autonomous tying and secure transportation of objects with cables remains a significant challenge. In this work, we present a novel method for autonomously securing and transporting objects using multi-layer hitches formed in midair by a team of aerial robots. Building upon prior work on polygonal hitch formation, we extend the framework to include layered cable interlacing that increases frictional grip and enables secure object grasping. We introduce two new manipulation actions: multi-layer tying and autonomous object release, completing the pipeline for aerial grasping and transportation. We develop a capstan-based analytical model that establishes an exponential scaling law for the effect of cable layers and provides a conservative guideline. The formation algorithm operates in parallel, ensuring scalability to large teams with constant execution time. We validate our system through simulation and hardware experiments, demonstrating fully autonomous object tying, lifting, and releasing using cables alone without human intervention.