The analysis of human walking stability using ZMP in sagittal plane

This paper investigates the difference of walking stability between the young and the elderly by using the method of zero moment point(ZMP) in sagittal plane. 3 young subjects and 3 elderly subjects participated in free walking experiment in a straight line on level ground. Motion capture system was used to collect the experimental data of lower limbs movement while walking. Experimental results show that in the comparison between young and elderly, there are some effective walking stability parameters, specifically including the horizontal distance (δ
_Zmp
) between ZMP and the center of mass of body, the horizontal distance (δ
_ankie
) between ZMP and the ankle joint, the linear relationship between δ
_ZMP
and gait speed, and the trajectories of ZMP in ground plane. These parameter criteria can be used to analyze dynamic walking stability for guiding the development of walking assistance devices.