Design And Analysis Of Pressure Measurement System Based On Spectral Analysis Using Fiber-Optic Fabry-P(?)rot(F-P) Pressure Sensors

The brain pressure refers to the pressure within the cranial cavity,which is also known as intracranial pressure.Due to the importance of the brain pressure and the specificity of its detection position,the measurement equipment of brain pressure puts higher and even harsher requirements on the sensor and the analytical method.Micro-pressure sensors play a very important role in the field of biomedicine because of their obvious advantages in invading the human body,and the measurement technologies based on this type of sensors have also been continuously growing.The optical fiber pressure sensors are light,small,and easy to embed into the body,and they also have obvious advantages such as high sensitivity,strong anti-interference,and strong multiplexing.In recent years,optical fiber sensing has become a research hotspot in the field of sensing technology,and it has also caused widespread attention among researchers in the field of brain pressure measurement.The purpose of this project is to design a set of brain pressure measurement system based on FP pressure sensor,spectrometer and LabView virtual instrument,and propose two optimization methods of spectral analysis.At the same time,it combines optical transmission technology,infrared light detection technology,and spectral processing technology to conduct experimental analysis and verification,and then completes and optimizes the designed measurement system.The system adds optical switch devices based on traditional laboratory measurement systems,enabling the system to measure the light source spectrum and the reflectance spectrum simultaneously,and then use the optimization methods proposed in this paper to analysis the spectral data more quickly and efficiently.Through the above innovations,the impact of light source power fluctuation and optical fiber optical path loss on the brain pressure measurement system is greatly reduced.As a result,the accuracy and stability of the measurement are greatly improved.At the same time,it also makes the measurement system get rid of the shackles of the traditional broadband light source,which greatly reduces the cost of the production and the system's volume.Therefore,this system has a good application and development prospects in the future medical field.This study also provides a good reference for future research and mass production of medical pressure measurement equipment.In this paper,the importance of the measurement of brain pressure and the development status of this field are explained first.Then the interference principle,classification and application fields of the FP pressure sensor are introduced in detail,and various demodulation methods are analyzed.Based on this,we designed the software and hardware of the measurement system,and then conducted a series of tests and analysis.The specific work of this article is as follows:(1)Through the research of the brain pressure measurement abroad and the study of the advantages of optical fiber pressure sensors,this subject identified pressure sensing devices as FP pressure sensors and started work on this basis.By investigating the current technological achievements of the FP pressure sensor,we have analyzed the principle of the FP pressure sensor used in this project.At the same time,we made a theoretical analysis of the traditional spectral analysis method of FP pressure sensors and proposed two optimized methods.(2)Based on the optimized methods proposed in this project,the selection and design of the hardware components of the measurement system were completed.We completed the design of the software of the measurement system using the method of mixed programming of Lab View and MATLAB.Using the serial port communication to control the optical switch,we achieved the purpose of switching the light source reference spectrum and the sensor reflectance spectrum automatically.This system has the advantages of low cost,small size,high stability and beautiful interface.(3)For the above methods,we performed a series of experiments and then analyzed the experimental data.Finally,the normalized wavelength analysis method was determined as the demodulation method of the subject.This method has the advantages of high linearity of measurement,large measurement range,and small interference from light sources.(4)We calibrated the measurement system in a dynamic pressure environment.The experimental results show that in the range of 0?1000mmHg,the linearity of the curve is as high as 0.998,the sensitivity is 0.17nm/mmHg,and the error is controlled within 0.25mmHg.(5)The temperature-sensitive characteristics of the brain pressure measurement system were measured experimentally at different temperatures.The experimental results show that the measurement system is less sensitive to temperature.In the temperature range of 36?40?,the temperature sensitivity is about 0.02nm/?.The error caused by the temperature change to the measurement system within 0.3mmHg range.