An evaluation method of human standing stability by applying the disturbance of swash plate fall

This paper proposes a swash plate disturbance application device for human standing stability evaluation. It is known that when a mechanical disturbance is applied to the lower body, the COP (center of pressure) trajectory of the human is closely related to the standing stability of the human. Based on this fact, the paper first proposes a swash plate disturbance application device to measure the COP trajectory when the mechanical disturbance is applied. A linear identification method, where the input is the disturbance and the output is COP trajectory, is used to get a human standing stability system model. The model is expressed by a transfer function which includes the parameters of poles and zeros. Using the identified parameters, a human standing stability index is proposed. By some swash plate disturbance experiments for human standing and system identification experiments under several experimental conditions based on the proposed method, parameters of stability system dynamical model are obtained. The proposed index is calculated using the parameters. Then, it is found that the stability index values according to the experimental conditions such as normal standing and tandem standing, which is known more unstable one and less stable one, are properly obtained.