Tether-based Robot Locomotion Experiments in REX-J mission

Locomotion is an important factor of astronaut support robots for construction, repair, or inspection. The requirements for it are long reach, smallness, and lightness. Tethers are good candidate because they can make long reach and are very light. They are also compact when they are reeled up. The authors have proposed a re-configurable tether-based locomotion method. In the concept, the robot attaches / detaches its tethers to / from handrails on spacecrafts and locomotes by controlling the length and tension of the tethers. From Aug. 2012 to May 2013, JAXA conducted the REX-J (Robot Experiment on JEM) mission which is the demonstration experiment of the proposed method on the International Space Station. This paper describes the results of the locomotion experiments.