Research On Human Blood Pressure Detection Method Based On Fiber Grating Pulse Wave

With the ageing of our society,the accelerating rhythm of modern life,the change of diet structure and the deterioration of the environment,cardiovascular and cerebrovascular diseases like hypertension and heart disease have become the main diseases threatening human’s health and life severely.Prevention and control of cardiovascular and cerebrovascular diseases has become one of the focuses in biomedical research.The fiber Bragg grating(FBG)sensor which possesses the merits of small size,high sensitivity,anti-electromagnetic interference and perfect combination with yarns,has the research value and application potential in the field of wearable sensors,and is of great significance to monitor the physiological parameters of human body under strong electromagnetic environment.A method of blood pressure monitoring based on pulse wave which uses FBG sensors has been studied in this paper on the basis of the early stage of the research group.The research content is divided into two parts:fiber Bragg grating pulse wave signal processing algorithm and establishment of human blood pressure estimation model based on multiple pulse characteristic parameters.With the characteristics of fiber grating pulse wave,a wavelet threshold de-noising combining with modified mathematical morphology has been proposed in signal de-noising works,and the length of mathematical morphology structural element based on the pulse cycle are chosen automatically in order to improve the effect of baseline de-noise.A method of feature extraction has been designed after the research of the actual physiological significance of pulse feature point,which improves the accuracy of extraction for peak and start point.The experimental result demonstrates that the SNR of the output pulse wave is doubled compared with that of the input pulse wave,and the accuracy of extract peaks and start point of pulse wave are over 97.2%and 97.6%within the allowable error range,respectively.An experimental platform of human body physiological multiple parameters detection is built,which can garther the FBG pulse wave,piezoelectric pulse wave and photoplethysmography pulse wave synchronously,and a signal processing software based on LabVIEW platform is programmed which can achieve de-noising of FBG pulse wave signal and feature extraction.A kind of personalized nonlinear blood pressure estimation method based on multiple pulse wave parameters has been proposed on the basis of the correlational research between pulse characteristics and human blood pressure.First of all,choose multiple pulse parameters which has higher relevance to blood pressure as modeling parameters;then analyze the actual function relationship between these parameters and blood pressure;finally,establish the pulse blood pressure estimation model by the least square fitting algorithm based on the parameters and actual function relationship mentioned above,to achieve cuffless continuous measurement of the systolic and diastolic blood pressure.According to the result of experiment,the average calculation error of systolic blood pressure and diastolic pressure calculated by the blood pressure estimation model is respectively 1.93±1.39mmHg and 2.05±1.56mmHg,which meets the international standard for blood pressure measurement requirements for non-invasive blood pressure measurement accuracy.On this basis,the volunteers were divided into four categories,and a universal blood pressure estimation method for each category of people was proposed.The experiment show that the calculation accuracy of systolic blood pressure and diastolic pressure calculated by the universal blood pressure estimation model is 3.56±2.68mmHg and 4.8813.76mmHg,respectively.By increasing the number of samples involved in each category,the accuracy of the general model can be further improved.The research achievements of this paper will provide reference for the research of human physiological parameters detection method based on Fiber Bragg grating sensing fabric,and provide important evidence for the development of wearable cuffless continuous blood pressure measurement technology.