Passive/active unified dynamic walking for biped locomotion

In order to implement walking efficiency and environmental adapting ability to a biped locomotion, it is required to combine passive dynamic walking and active one. In this paper, a passive/active unified dynamic walking for biped locomotion was proposed. Firstly, a passive/active unified actuator that has a torque detector and is actively controlled by zero torque feedback control was proposed and developed. Next, a free moving joint used in passive motion was implemented analytically and experimentally to a one-joint one-link and a two-joint two-link mechanism with a reduction gear using this developed actuator. Furthermore, in order to apply it to a biped walking robot, a passive/active unified dynamic walking control algorithm was proposed. Moreover, 2-D passive/active unified dynamic walking of a three-joint four-link biped robot was implemented experimentally by applying self-excited control to the passive walking phase of the swing leg. Finally, we showed the energy-efficient walking using the proposed method by comparing Specific Cost of other types of dynamic walking, and mentioned its adaptability to disturbances and unknown environment.