Abstract
In this paper, the limp posture during the bipedal locomotion of ratitaes were examined by creating simple link models based on videotapes of each bird during locomotion. The model was balanced by comparing them with photos of skeletons and using known bone length ratios. Two methods were used to determine the location of the center of mass (MC), in which both methods confirmed the same location. From these models, the exhibition of long double-leg support phases and minute CM vertical motion became apparent. The kinetics of locomotion shows similarities with models using the Linear Inverse Pendulum Method. Analysis of limp posture by the introduction of manipulabuility ellipsoids suggests that limb posture of both support and swing legs are advantageous for bipedal locomotion.
