Controlling walking behavior of passive dynamic walker utilizing passive joint compliance

Abstract

The passive dynamic walker (PDW) has a remarkable characteristic that it realizes cyclic locomotion without planning the joint trajectories. However, it cannot control the walking behavior because it is dominated by the fixed body dynamics. Observing the human cyclic locomotion emerged by elastic muscles, we add the compliant hip joint on PDW, and we propose a "phasic dynamics tuner" that changes the body dynamics by tuning the joint compliance in order to control the walking behavior. The joint compliance is obtained by driving the joint utilizing antagonistic and agonistic McKibben pneumatic actuators. This paper shows that PDW with the compliant joint and the phasic dynamics tuner enhances the walking performance than present PDW with passive free joints. The phasic dynamics tuner can change the walking velocity by tuning the joint compliance. Experimental results show the effectiveness of the joint compliance and the phasic dynamics tuner.