Abstract
This paper deals with the problem of stability and health condition in a human stance posture control system by analyzing its dynamics from the view point of control engineering. The stance of a subject is based on a number of internal body functions, and is arrived through the combination of nerve centers connecting receptor organs such as inner ear vestibules, sight and kinesthesia. Therefore, a subject's stance posture system is regarded as a sort of barometer for comprehensively evaluating the entire body. This dynamics was discussed from the model of several subjects aged from 20 to 60 years old. It was found from experiments that the "fluctuation" of a body swaying was a key factor in evaluating health conditions of a stance posture control system. Further we could not find any obvious relationship between the stability and the health condition in this system.
