Climbing loose surfaces with steep slopes using a small, lightweight push-rolling rover with minimal configuration

Abstract

Owing to the payload limitations, some organizations are focusing on small, lightweight wheeled rovers for planetary exploration. Planetary and lunar surfaces feature weak soils and slopes that pose mobility challenges for wheeled rovers. Studies have shown that push–pull locomotion can improve climbing ability. Such rovers lock one pair of wheels relative to the ground while driving the other like an inchworm. Conventional rovers have large masses ranging from 10 to nearly 1,000 kg. However, some studies are now focusing on small rovers of masses from under 1 kg to 20 kg. For such rovers, traveling on granular surfaces with steep slopes and low slips remains an experimental challenge. This study develops a small, lightweight push-rolling rover and evaluates its ability to climb steep slopes. To meet size requirements, the rover uses a minimal configuration. Experiments to measure resistance and drawbar pull forces during push-rolling revealed that a lugged wheel and dynamic sinking behavior using an intentional slip increased the total thrust forces. Additionally, travel experiments showed that the developed rover, with its optimal configuration, demonstrated a high climbing ability on slopes greater than 30°.