Hopping direction controllability for small body exploration robot

Hopping is effective mobility for exploration robot on small body. To explore small bodies, a mobile robot is required to move to target points. In case of exploration of microgravity environment by a hopping locomotion, hopping trajectories cannot be controlled after a robot hops. To move to target points, hopping direction and velocity should be controlled at takeoff. The authors proposed a, hopping robot, which consists of three masses, two linear actuators and a spring. This paper discusses how to control a hopping direction of the proposed robot in microgravity environment. When the robot hops, the friction force between the robot and the ground becomes larger. The simulation results show the controllability of a hopping direction even if there is a slip on a ground. The controllability is also confirmed by the free fall experiments.