Robotic Gripper for Payload Capture in Low Earth Orbit

Abstract

The consensus to a study phase for an Intermediate eXperimental Vehicle (IXV) successor, a preoperational vehicle called Space Reusable Integrated Demonstrator for European Return (SPACE RIDER), has been recently enlarged, as approved during last EU Ministerial Council. One of the main project tasks consists in developing SPACE RIDER to conduct on orbit servicing activity with no docking. SPACE RIDER would be provided with a robotic manipulator system (arm and gripper) able to transfer cargos, such as scientific payloads, from low Earth orbiting platforms to the SPACE RIDER cargo bay. The platform is a part of a space tug designed to move small satellites and other payloads from Low Earth Orbit to Geosynchronous Equatorial Orbit and vice versa. A study on this robotic technology is here presented. This research is carried out by Politecnico di Torino and Thales Alenia Space Italy. The system configuration of the robotic manipulator is first described in terms of volumes and masses. The considered housing cargo bay requirements in terms of volume (< 100 l) and mass (< 50 kg) combined with the required overall arm dimensions (4 m length), and mass of the cargo (5–30 kg) force to developing an innovative robotic manipulator with the task-oriented end-effector. It results in a 7df arm to ensure a high degree of dexterity and a dedicated end-effector designed to grasp the cargo interface. The gripper concept here developed consists in a multi-finger hand able to lock both translational and rotational cargo degrees of freedom through an innovative under-actuation strategy to limit its mass and volume. A configuration study on the cargo handle interface has also been performed together with some computer-aided design models and multibody analysis of the whole system to prove its feasibility. Finally, the concept of system control architecture is defined.