Actively Articulated Wheel-on-Limb Mobility for Traversing Europa Analogue Terrain

Published in Conference on Field and Service Robotics, 2019

W. Reid, G. Meirion-Griffith, S. Karumanchi, B. Emmanuel, J. B. Brendan Chamberlain-Simon, J. Bowkett, and M. Garrett

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Exploring the water-rich surface of Europa is a desirable planetary ex-ploration objective for the coming decades. Knowledge of the Europan terrain isrelatively uncertain and therefore to perform mobile surface operations a versatilemobility system capable of adapting its locomotion is desirable. Our work sum-marizes preliminary efforts to evaluate a variety of wheel-on-limb mobility modeson Europan analogue terrain populated with unstructured salt-evaporite formations.A redundant wheel-on-limb quadruped,RoboSimian, has been adapted to performtraverses over unstructured terrain with obstacles up to 50 cm tall (1.6 times itswheel diameter). Multiple mobility modes that are combinations of wheeled andlimbed motion primitives are proposed and evaluated over varying roughness ter-rain as a function of energy usage. In combination with these mobility modes, amode-agnostic actively articulated suspension control scheme that maintains groundtraction, regulates chassis orientation and prevents suspension saturation is pre-sented. The controller uses an inverse kinematics solver that leverages pre-computedlookup-tables for each limb. This is shown to be simple yet effective in the field andis able to scale to a robot with 32 degrees-of-freedom.

Recommended citation: W. Reid, G. Meirion-Griffith, S. Karumanchi, B. Emmanuel, J. B. Brendan Chamberlain-Simon, J. Bowkett, and M. Garrett, “Actively Articulated Wheel-on-Limb Mobility for Traversing Europa Analogue Terrain,” Submitted to Conference on Field and Service Robotics, 2019.