Hopping motion analysis of 'superball'-like spherical robot based on feedback control

This paper deals with hopping motion analysis of spherical robot with a typical impact condition like 'superball'. A horizontal velocity of super ball after an impact depends on the angular velocity before the impact where it doesn't slip at the contact point. Our robot model consists of an elastic spherical shell with such an impact condition and of an internal rotary input. Assuming the perfectly elastic impact in a vertical direction, a feedback control strategy for generating the horizontal velocity after an impact by the rotary input during flying phase is derived. Simulation results show that some hopping motion is achieved by the proposed method. In addition, this paper shows the possibility and necessary condition that a climbing motion with impacts against two parallel vertical planes is achieved.