智能服装中光纤Bragg光栅心音检测方法的研究

Research on heart sound measurement based on fiber Bragg grating for intelligent clothing

研究基于光纤光栅智能服装心音检测的理论和方法。根据光纤光栅应变效应和圆形膜片振动原理,建立了心音传感数学模型,推导出心音灵敏度计算公式。设计了光纤光栅心音传感器结构并制作出样品,其灵敏度理论值为957.11 pm/kPa。用所设计的传感器对人体心音进行实测,反射波长变化范围约70 pm。在体温不变的情况下,光纤光栅反射波长漂移主要由心音和呼吸作用引起,提出利用小波消噪进行心音提取的算法。数据处理结果表明:在1 kHz采样频率下,用db4小波消噪后的心音数据与标准心音传感器输出具有相同的心音特征,证明了所提出的光纤光栅心音检测方法的可行性。

The theory and method of human heart sound measuring are researched for intelligent clothing based on fiber Bragg grating.In terms of strain effect of fiber Bragg grating and the vibration principle of round diaphragm,the mathematics model of heart sound sensing is established,and the expression of heart sound sensitivity is deduced.A fiber Bragg grating heart sound sensor is designed and fabricated and its sensitivity is 957.11 pm/kPa in theory.The designed sensor is used to measure human heart sound,the reflected wavelength excursion range is about 70 pm.When the temperature is invariable,the reflected wavelength variety of fiber Bragg grating is mainly caused by heart sound and respiration,and a heart sound extracted arithmetic is proposed based on wavelet decomposition theory.The data processing result shows that when the sampling frequency is 1 kHz,the heart sound data by using the db4 wavelet decomposition has the same characteristics as a standard heart sound sensor.The experimental result proves that the proposed heart sound measurement method and signal processing arithmetic are feasible.