The concept of rod-driven locomotion for spherical lunar exploration robots

A spherical robotic probe has several advantages in rough environments and has therefore raised interest for application in planetary exploration. A sphere is well-suited to protect high-sensitive payloads, however, the locomotion system for planetary surfaces raises several challenges. This paper presents a novel locomotion system consisting of linear actuators which are usable in a multi-functional fashion. Apart from pushing and bringing leverage for locomotion the extendable rods enable a tripod mode for improved sensing. The developed solutions offer a mathematical-physical system description, simple algorithms for the control of locomotion and balancing as well as general calculations for determining the maximum achievable performance parameters of such a robot. The first built prototype shows the basic suitability of the system and reveals directions for further research.