A Three-dimensional Balance Control Model of Quiet Upright Stance Based on an Optimal Control Strategy

INTRODUCTION Many existing balance control models have adopted a single-segment inverted pendulum to model the human body, and have focused on investigating postural sway only in the sagittal plane (e.g. Maurer et al., 2005). However, evidence indicates that postural sway in the frontal plane is important, and able to account for different balance control mechanisms as well (e.g. McClenaghan et al., 1996). Thus, a simple two-dimensional balance control model that cannot simulate medial-lateral (M/L) postural sway is not able to sufficiently reflect how humans control upright posture. The purpose of this study was to develop a balance control model that can accurately simulate postural sway in three-dimensional space.