抄録
Estimation of stability of standing during recovery phase after frontal inclination using video-captured posture is discussed. Two-link inverse pendulum models is applied to the human body to estimate viscoelastic coefficients, i.e. natural frequency and dumping ratio, of ankle and waist during the recovery phase only. One subject is asked to stand still, incline forward as far as possible and return to the original posture in subject's eyes-opened, eyes-closed and one-legged condition. The estimated viscoelastic coefficient of ankle and physical parameters such as body weight, length and moment of rotational inertia are applied to one-link inverse pendulum to derive natural frequency and dumping ratio of second order transfer function which simplifies the dynamics of standing human. The experimental results show that the dumping ratio maximizes during eyes-opened condition and minimizes during one-leg condition. It is suggested that the damping ratio indicates the ability of dynamical postural control.
