Novel Approach to Analyze All-Round Kinematic Stability During Curving Steps

Abstract

From the viewpoint of the stability of biped walking, the stability for both anteroposterior, lateral, and diagonal directions should be considered owing to the frequent occurrence of turning and curving motions in the daily environment. In this study, a measure called the all-round margin of stability (MoS) is proposed to evaluate the kinematic balance of the all-round direction. A curving experiment was performed to analyze the characteristics of the all-round MoS. The curving gait was recorded with and without the restriction of hip rotation. The all-round MoS of trials were classified using cluster analysis, and the characteristics of curving motion were extracted from gait parameters using factor analysis. By comparing the characteristics of the all-round MoS and factor scores, the features of the all-round MoS were discussed. The results suggest that the effect of the parameters on the MoS, such as the velocity of the center of gravity and step width, matched the characteristics of the all-round MoS. Thus, the effect of the range of motion of hip rotation on curving gait was analyzed using an all-round MoS. The all-round MoS helps visualize the anisotropy of balance, which then enables estimation of the direction with high fall risk. Furthermore, the all-round MoS enables to evaluate and improve the performance of gait assist devices such as exoskeletons. This study proposes the concept of all-round MoS as the method to evaluate balance in diagonal direction especially for complex gait.