Earth’s orbital space is a busy and dangerous place to work, an environment filled with very specific, highly complex challenges… and lots of space debris. On-Orbit-Servicing (OOS) and On-Orbit-Assembly (OOA) are two ways to make spaceflight more sustainable; building, maintaining, and repairing spacecraft in orbit extends their lifetime and reduces the amount of space junk floating around our planet. 

To minimise the need for inherently risky human interaction in servicing, maintenance, and assembly tasks, the application of robotic systems has obvious advantages. However, space robotic systems are traditionally created for specific purposes or applications, and often require a vast amount of design effort and cost, often making them unfeasible for many missions. 

A collaboration between the Institute of Space Systems (IRAS) at the Technical University of Braunschweig and the Institute of Structural Mechanics and Lightweight Design (SLA) at RWTH Aachen University, has led to a project to modularize a manipulator for use in space applications by developing an unconventional kinematic chain with a joint rotation axis offset of 45°. This modular manipulator can adapt itself physically, modifying its length and degrees of freedom during operation as necessary.

The HOMER team have developed two on-Earth demonstrators; the ‘Little Inspection and Servicing Arm’ (LISA) and ‘Medium-sized Arm for Reconfiguration and Grappling Exercises’ (MARGE) to determine the operating loads, design of the actuators, design of the joints, and design and optimisation of the structure.

Racks for electronics within each module house devices for power handling, controls and communication. Kvaser’s Leaf Light HS v2 CB control servo drives from Copley Controls. Actronic Solutions provided advice and support to the project, suggesting the PCB-based CAN interfaces and supplying the servo drives.

Space isn’t the only application for the concept. Taking the idea of minimising the need for inherently risky human interaction in servicing, maintenance, and assembly tasks, it could also be used in other harsh environments such as the ocean floor or in the confined, highly-radioactive space of a nuclear reactor. The modular, highly redundant design could also bring this technology within the reach of many more projects since it increases flexibility during production, reducing tooling times and enabling swift adaptability to create a variety of products. 

Kvaser wishes the HOMER team the very best for continued success with their project. And who knows, maybe in a few years we’ll be talking about subsequent terrestrial demonstrators BART and MAGGIE!

The information was published in a paper entitled ‘Fully Modular Robotic Arm Architecture Utilizing Novel Multifunctional Space Interface’ by C. Zeis₁, C. A. de Alba-Padilla₂, K.-U. Schroeder₁, B. Grzesik₃, E. Stoll₃ that was published in 11TH-EASN IOP Conf. Series: Materials Science and Engineering 1226 (2022) 012096, IOP Publishing doi:10.1088/1757-899X/1226/1/012096

₁ Institute of Structural Mechanics and Lightweight Design, RWTH Aachen
University, Wuellnerstr. 7, 52066 Aachen, Germany
christopher.zeis@sla.rwth-aachen.de

₂ Institute of Space Systems, TU Braunschweig, Hermann-Blenk-Str. 23, 38108
Braunschweig, Germany

₃ Chair of Space Technology, TU Berlin, Marchstr. 12-14, 10587 Berlin, Germany