Abstract
This study focus on the balance model describing human body dynamics during standing on a moving board. In general, it is very difficult to build the balance model because the sensory feedback system is unknown. To establish the trend of the human dynamics, we implemented frequency response test and tried to build an appropriate model. In the test, phase delay arises in low frequency range below 0.2 Hz. We assume that the delay is generated by velocity feedback of the board via visual sensing. Under the assumption, we built a model and identified feedback parameters using least square method. Then a reasonable and stable model to agree the characteristics with frequency response diagram in low frequency range is obtained. Additionally, we checked posture angle of the subject standing on the board which moves in constant velocity. From the result, we found that subject’s posture inclines toward rearward according to the velocity of support surface. The phenomenon accords with the proposed model obtained and a constant of proportionality between velocity of the support surface and posture angle of the subject is approximate to the feedback parameter identified from frequency response test. As a result, validity of the proposed model is verified by frequency response test and constant velocity test.
