B108 Evaluation of influence of surface shape of wheel on traversability of wheeled mobile robots on loose soil

Abstract

Planetary rovers play a significant role in surface explorations on the Moon and/or Mars. However, because of wheel slippage, the wheels of planetary rovers can get stuck in loose soil, and the exploration mission can fail because of this situation. To avoid slippage and increase the wheels' drawbar pull, the wheels of planetary rovers typically have lugs, i.e., grousers, on their surface. In this study, we conducted experiments using two-wheeled testbeds in a sandbox to evaluate the influence of lugs on the traversability of wheeled mobile robots. According to the experimental results, we confirmed that the lugs have a greater effect on the travesability of the mobile robots than the increase of the effective diameter of the wheel. Furthermore, we concluded that the bulldozing force of lugs, rather than shear stress between lugs at the tip, contributes to the traversability, especially over steep slopes.