An Adaptive, Reconfigurable, Tethered Aerial Grasping System for Reliable Caging and Transportation of Packages

Aerial robot development has gathered steam in recent years for applications such as package delivery and transportation of arbitrary payloads, both in academia and business. However, current solutions for Unmanned Aerial Vehicles (UAVs) based transportation of large objects and/or parcels rely on some form of standardization of packaging. This design constraint greatly limits the applicability of the autonomous package delivery drone concepts. In this paper, we propose a reconfigurable, tethered aerial gripping system that can allow for the execution of a more diverse range of package handling and transportation tasks, employing autonomous aerial robots. The system combines a reconfigurable, telescopic, rectangular frame that is used to conform to the parcel geometry and lift it, and a net system that is used to secure the parcel from the bottom, facilitating the execution of caging grasps. This combination provides reliable aerial grasping and transportation capabilities to the package delivery UAV. The grasping and transportation process used by the proposed concept system can be divided into three stages: i) the reconfigurable, telescopic frame conforms to the parcel geometry securing it, ii) the package is lifted or tilted by the frame's lifting mechanism, exposing its bottom part, and iii) the net is closed, caging and securing the package for transportation. A series of airborne gripping and transportation trials have experimentally validated the system's effectiveness, confirming the viability and usefulness of the proposed concept. Results demonstrate that the prototype can successfully secure and transport a package box. Furthermore, the complete system can be tethered to any type of aerial robotic vehicle.