Passive dynamic walking of combined rimless wheel and its speeding-up by adjustment of phase difference

This paper investigates passive dynamic walking of a combined rimless wheel that consists of two identical 8-legged rimless wheels. By using the mathematical model, we numerically show that stable passive gaits can be generated on a gentle slope, and that the walking speed is dramatically improved by adjusting the phase difference between the fore and rear legs. We then discuss the inherent speeding-up mechanism from the potential barrier point of view. Furthermore, the validity of the derived results is evaluated by using an experimental machine.