Concept Study of a Small-Scale Dynamic Legged Robot for Lunar Exploration

• Main Authors: Trentini, Marco, Arm, Philip, Valsecchi, Giorgio, Kolvenbach, Hendrik, id_orcid:0 000-0003-1229-7537, Hutter, Marco, id_orcid:0 000-0002-4285-4990
• Format: Conference Object
• Language: English
• Published: International Astronautical Federation 2023
• Subjects: Legged Robotics; Space Robotics; Space Exploration; Lunar exploration; South Pole; South pole
• Online Access: https://hdl.handle.net/20.500.11850/637579; https://doi.org/10.3929/ethz-b-000637579

When it comes to the exploration of the lunar surface, many high-reward targets, such as the craters at the lunar south pole or the Aristarchus Plateau, lie in hard-to-reach areas due to steep slopes, crater rims, and unstructured terrain. Therefore, such high-risk high-reward targets are currently out of human and robotic reach. Legged robots present a promising approach to exploring hard-to-access targets on the Moon. Legged robot prototypes have shown impressive locomotion capabilities in sloped, unstructured terrain in analog environments. However, despite their success in locomotion validation tests, we currently lack a target- and mission-specific analysis and design of the locomotion pattern, the thermal requirements, and the power system. We have set our goal to develop a small-scale, legged, technology demonstration robot. In this paper, we present our conceptual work on such a robot, targeting a traverse distance of 200 m and a payload capability of 1.5 kg. Our study showcases a basic locomotion study that identifies a feasible gait and its power requirements on representative terrain. We then lay our major focus on a thermal and power model considering the environment, the robot, and task schedule with sufficient accuracy to fulfill our self-defined mission success criteria. We also investigate the influence of the system’s emissivity and absorptivity on the regulation of the robot’s temperature. The simulation results suggest feasibility for missions at latitudes of 24°S and 75°S using a small-scale dynamic legged robot. However, it becomes clear that further research is required to validate the accuracy of the model. Research in solar panel degradation due to dust perturbation in legged robots will be necessary as the solar panel degradation shows a significant impact on the mission duration. Furthermore a precise soil-robot view factor needs to be determined. The determination of a realistic multi layer insulation concept for SpaceHopper in a lunar environment will be necessary to validate the ...