Quantifying one's mechanical ability to control upright balance based on the probability of recovery

摘要

Control of balance is an inherent objective in human whole-body movements. It is essential for movement researchers as well as clinicians to quantitatively know how good the balance is at a body posture or at every moment during a task. In this research we suggest a method to quantitatively assess one's upright stability at a given body state, which assigns a value to a pair of person-state, based on the probability of avoiding a fall initiation. State space is, first, mapped into the stabilizer-input space taking advantage of stable manifolds, and then the probability of a stabilizer input to be applicable by a specific person is obtained based on strength data and kernel density estimation method. This probability is defined as a metric for upright balance for a person-state. It, therefore, describes how possible the control of balance is, or how safe being at that state is, for the specified person. We also compare our new metric to the conventional one, the so called margin of stability.