Wheel-Based Stair Climbing Robot with Hopping Mechanism - Fast Stair Climbing and Soft Landing Using Vibration of 2-DOF System -

We propose a simple hopping mechanism using the vibration of a two-degrees-of-freedom (DOF) system for a fast stair-climbing robot. The robot, consisting of two bodies connected by springs, hops by releasing energy stored in springs and travels quickly using wheels mounted on its lower body. The trajectories of bodies during hopping change based on design parameters such as the reduced mass of the two bodies, mass ratio between the upper and lower bodies, spring constant, and control parameters such as initial contraction of the spring and wire tension. This property allows the robot to quickly and economically climb stairs and land softly. In this paper, the characteristics of hopping for the design and control parameters are clarified by both numerical simulation and experiments. Furthermore, fast stair climbing and soft landing are demonstrated.