從一個人的平衡能力中能得到很多訊息，如健康狀況、老化程度等，因此受到相當程度的重視。目前常用來做為人體平衡機制研究的訊號主要是人體壓力中心訊號(center of pressure, COP)，而壓力中心訊號的量測是藉由生物力學量測設備測力板來作量測。不過由於測力板的造價昂貴，且量測上有諸多不便，本研究利用電容式低頻三軸加速規訊號針對人體平衡能力作評估，取代過去常用的測力板。由於人體不停擺動，使得加速規之鉛直方向於重力加速度方向之分量為時變問題，利用將訊號分為數段，各別做主成分分析的方式，將訊號降維至平面訊號，並消除垂直方向重力加速度對水平分量訊號之影響，藉以模擬壓力中心訊號，建立兩者間之轉換關係，使加速規量測之訊號能用以同壓力中心訊號進行人體之平衡能力評估。;Most people evaluate human balance ability by analyzing the center of pressure (COP). However, the force plate which is used to measure the COP is normally expensive and is limited for measurement capability. In this study, we evaluate human balance ability through the measurements of capacitor-type accelerometer. The principal components analysis (PCA) is employed to reduce the influence of gravity component on the horizontal components while the accelerometer tilts inevitably. The signals relationship between the COP and the acceleration will be derived, so that the measurements of accelerometer can be utilized for evaluating the human balance ability.
