A Soft Spherical Robot for Lunar Crater Exploration

Abstract

The paper presents the design and construction of a new class of spherical robot. The robot consists of two main parts, an inner mobility mechanism and an inflatable outer spherical shell. In particular, the minimalist geometry of the spherical robot and its soft nature make descent into lunar craters possible, exploring dark and cryogenic terrain unreachable by human crew. However, outfitting a spherical robot with a soft outer shell will introduce changes in its dynamics that are do not exist with a rigid one. This paper will model how those dynamics affect the robot and influence the shell design. Descriptions of the robotic pendulum and shell prototypes will be presented. A model describing the dynamic changes with respect to design parameters will also be derived. The proposed prototypes will be characterized with the model to predict the robot's new dynamics.