Spaceclimber: A Six-Legged Robot For Extraterrestrial Surface Exploration In Unstructured And Steep Terrain

Abstract :

In this paper we describe the biologically inspired, energy-efficient, and adaptively free-climbing robot SpaceClimber developed for extraterrestrial surface exploration. Regions, such as rock fields, which require highly mobile systems in order to carry out in-situ examinations, typically belong from a scientific point of view to the most fascinating places on Moon and Mars. Their attraction is only topped by crater and canyon walls which are even more difficult to explore. It is assumed that from these slopes, comparable to slopes on the earth, it is possible to get access to a variety of sedimentary layers from different eras. Therefore, these places are predestined for exogeological and exobiological investigation. Of particular scientific interest on the Moon are the asteroid craters at the poles, where it is expected to find old (inter)-stellar particles as well as volatile substances, e.g., frozen water. So far, all mobile robots deployed in extraterrestrial surface exploration missions are based on wheeled driven concepts with passive suspension systems which provide limited mobility on fine-grained soil surfaces and in steep gradients. SpaceClimber proved that legged systems present a very suitable solution to future missions in unstructured, uneven terrain, in particular in craters. The developed system was tested and evaluated on relevant terrain regarding energy efficiency and stability. As high stability in steep terrain is of utmost importance, these experiments were also performed to identify suitable parameter sets to modify the posture and walking pattern of the robot depending on the inclination and surface typ.