Passive dynamic of the simplest walking model: Replacing ramps with stairs

Passive dynamic of the simplest walking model is considered for stepping motion. The only variable is the ratio of the stair height to the robot leg length. It exhibits period-one stable limit cycles and then period doubling route to chaos. Since the results are comparable with walking down a shallow incline, we show the similarities and differences between these two kinds of passive walking to specify the role of surface profile in walking stability.