Based On The Temperature Compensation Bragg Grating Pressure Sensor And Signal Processing Research

The fiber Bragg grating(FBG) become one of the all-fiber passive devices with the fastest developing speed in recent years,when it is used to a sensor system,it can check strain,temperature,pressure,acceleration,etc.Optic fiber grating sensor gradually Optic fiber grating sensor gradually become the research focus among the sensors because of the excellent properties such as its small size,light weight,high accuracy, immunity to EMI and high resistance to corrosive environments,and its application is a field in the ascendant,there are very wide development prospects.The work of this paper focuses on research on fiber Bragg grating stress sensor.including the basic theory of fiber grating,principles of a fiber Bragg grating sensor,cross sensitivity,enhanced sensitivity technology,temperature compensation, signal demodulation technology for fiber Bragg grating,and so on.Firstly,we introduced the characteristic of fiber Bragg grating and its current development trend at home and abroad,explained the theory of the fiber Bragg grating coupling model and sensing mechanism of fiber Bragg grating,analyzed the cross sensitivity of temperature in fiber Bragg grating pressure sensing and method of severing cross sensitivity.further more,to overcome the cross sensitivity problem,we have designed Optical fiber Bragg grating stress sensors based on thin-walled cylinder structure and plane sheet structure,proposed the passive temperature-compensating and Polymer package technique,by this means,we have not only solved the cross sensitivity problem caused the temperature changing but also increased the stress sensitivity of stress measurement.Secondly,we analyse commonly used demodulation technique for fiber Bragg grating,a new demodulation technique for fiber Bragg grating based on FPGA is presented.Finally,we setup stress sensing model of fiber Brgag grating,and completed the pressure-sensitive experiments,temperature-sensitive experiments,as well as cross-sensitive to pressure and temperature experiments,researched the fiber Brgag grating characteristics of temperature and stress,including repeatability,hysteresis error,linearity,accuracy.The experimental results indicated that the use of passive temperature compensation as well as real-time temperature of residual effect of the initiative amendment to the temperature sensitivity can achieved the accurate measurement of pressure,pressure measured up to 50 MPa,the pressure sensitivity to achieve 0.036 nm/MPa,repeatability error is 0.75%,hysteresis error is 1.84%,and the basic error is±0.89%,But also can be achieved on the pressure,temperature measurements at the same time.The result also show that this structure FBG pressure sensor can meet the measurements of different range and sensitivity by changing the structure of parameters,such as substrate material,geometry size.