Study on traveling performance for variable wheel-base robot using subsidence effect

In order to traverse the Lunar and Martian surface, planetary exploration rovers, which is equipped with cylindrical typed wheels, has been required high traveling performance. However, the cylindrical wheels of conventional rovers are easy to sink or slip on loose soil. Therefore, the rovers cannot move forward or backward in order to escape from the corresponding severe areas. In this study, we focus on an inching worm locomotion method to solve such a problem. The inching worm locomotion is a method that utilizes bearing force, which is generated between the ground and wheel when the wheel shears the ground. A few previous studies have investigated a method to traverse the loose soil. Further, a static sinkage was used to obtain bearing force in previous studies. This study proposes an advanced scheme that uses large sinkage to increase the traction. In order to confirm the effect of bearing force when the wheel sinkage is large, we performed traveling experiments on loose soil. From experimental results, the traveling performance of the robot, which is operated with the proposed scheme, indicated higher than that of the conventional scheme.