Exploiting Friction for the Locomotion of a Hopping Robot

For the locomotion of animals and machines, the friction between the body and the ground is one of the most crucial factors for stability and mobility. In this paper, we investigate how the friction could be exploited for the purpose of adaptive locomotion. At first, we propose two conceptual working hypotheses, especially focusing on two important issues, (1) how to control the friction to increase the stability of a locomotive system, and (2) how the friction could mobilize a system for a form of adaptive locomotion. Secondly, by using a hopping robotic platform we have developed, we evaluate the proposed ideas with three experimental case studies. The experimental results show the statistical plausibility of the proposed idea of increasing the stability of locomotion. Furthermore, it is shown that, by properly taking advantage of the friction, the robot could enlarge the repertoir of locomotion behaviors, which could presumably enhance the adaptability of robot locomotion.