A rocking period control method for a biped quasi passive walker using a mechanical oscillator

A passive walker is a kind of robot that consumes low energy through body dynamics. However, it is difficult to stabilize it in various environments, because it is hard to synchronize the rocking period of the robot with the swing leg period. This research developed an online period control method to solve the stability problem and realize ascending slope for a biped quasi passive walker. A mechanical oscillator is used to control the robot utilizing frequency entrainment. The Van der Pol equation and a PI controller were utilized to determine the target path of the mechanical oscillator. Finally, the validity of the proposed methods was analytically examined by numerical simulation ODE (Open Dynamics Engine).