Active Tethered Hook: Heavy Load Movement using Hooks that Move Actively with Micro UAVs and Winch System

In this paper, multiple micro UAVs (Unmanned Aerial Vehicles) are used to carry small hooks tethered to a heavy load, providing movement of the load within a three-dimensional workspace. We propose an active tethered hook. By moving and attaching the hook to an elevated location and winding the wire with a winch mechanism attached to a load holder, a heavy object can be moved that far exceeds the payload capability of a micro UAV. An RGB-D camera is mounted on the load holder to detect a suitable position to hook at the elevated position, measure the relative position between the micro UAV and the target and perform position control based on the feedback. We verified the hook attachment using this method and examined the hook selection method according to the conditions. Through experiments, it is confirmed that the detection of a rod-shaped object using the point cloud and the position measurement of the micro UAV using a marker were executed accurately. We also confirmed and demonstrated that it is possible to attach the hook to a target in autonomous flight.