Passive walking robot Quartet

In this paper, passive walking of the eight-legged robot Quartet that has simple straight legs, and is also constrained to have two degrees of freedom for the simplicity of its motion, is described. It is known that a 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, birfurcation that occurs along with the increase of slope angle and finally leads to chaotic gait is discussed. In walking experiment, some kind of trajectory stability can be observed