A discharging mechanism for a lunar subsurface explorer with the peristaltic crawling mechanism

To elucidate planetary origins and develop suitable bases for human operations, the subsurface of the planets must be investigated. Previously, we have developed a planetary subsurface excavation robot with the peristaltic crawling mechanism. This robot consists of two units; a propulsion unit and an excavation unit. The propulsion unit operates by peristaltic motion of three subunits, while the excavation unit is fitted with an earth auger. However, because underground soil is not smoothly discharged from the spout when it is below surface, this robot cannot continuously perform subsurface excavation. To solve this problem, we have developed a discharging unit that automatically conveys the soil from the spout to the ground surface. In this paper, we explain the function of the proposed discharging unit. Next, we develop the unit and experimentally evaluate its ability to remove underground soil. The unit is then attached to an excavation robot moving under propulsion. We conclude that the discharging unit can operate efficiently below surface.