Motion analysis and experiments of passive walking robot QUARTET II

In this paper, passive walking of the eight-legged robot QUARTET II that has simple straight legs, and is also constrained to have two degrees of freedom for the simplicity of its motion, is described. The legged robot can continue to walk down a slight slope steadily without any actuation if appropriate initial conditions are given. Since no control input, except for gravitational torque, is applied to the robot, more natural gaits compared with those of conventional actuated walking robots are expected. In walking simulation, trajectory stability and bifurcation that occurs along with the increase of slope angle and finally leads to chaotic gait are discussed. In walking experiment, some kind of trajectory stability and bifurcation can be observed