Design And Research On Push-pull Double Fiber Bragg Grating Based Accelerometer

Starting from the nineties of last century, many domestic and foreign research institutions and scholars in the field of fiber grating sensor technology efforts among research, opened up a new era of fiber Bragg grating. Fiber Bragg grating based accelerometer develops relatively rapid in many of FBG sensors. In the production and all areas of life, we need to make dynamic real-time analysis on variety vibration to ensure the safety of production and life. In many applications, which, based on fiber grating based accelerometer relative to the current widespread use of electromagnetic vibration accelerometer, it showed many advantages, such as simple structure, intrinsic safety explosion-proof, high temperature, high accuracy, resistance to electromagnetic interference and low power consumption.Into the twenty-first century, many domestic and foreign research institutions launched a section on marine seismic waves and the seabed seismic monitoring crustal new sensor system. Accelerometer based on fiber grating due to its simple structure, low power consumption and highly pro-Lai, its growth rate is fastest. Throughout the monitoring sensor system, the current work is mainly based on the study of fiber Bragg gratings which made with a simple mechanical structure and low complexity demodulation system of the accelerometer sensor.In this paper, on the basis study of fiber grating sensing technology as well as principles and techniques of achieve acceleration measurement system, combine with the practical application problems, a new type of double fiber grating accelerometer design and demodulation system has been advanced.The main contents are:First of all, starting from the theory of fiber grating sensor, analyze the characteristics of fiber Bragg grating strain sensing. A new type of optical fiber grating acceleration sensor design which use two fiber Bragg grating as the sensing part has been advanced. Make the mathematical model of advanced FBG accelerometer to analyze the mechanical properties and its characteristic equation. According to the theoretical and FEM analysis, confirmed the advanced FBG accelerometer to achieve acceleration measurement. Introduce the mechanical structure design of the accelerometer and the processing and assembly of it.Secondly, according to the analysis and comparison of currently more mature signal technology, for the different dual-fiber grating structures and their spectral characteristics, Propose IM-DD system as the optical signal demodulation of the advanced FBG accelerometer. Derive the relationship between the light intensity of dual fiber and the relative strain, and then make the theoretic curve. Finally confirmed the intensity demodulation technique can be used directly as a new accelerometer demodulation system. Detailed introduce the entire sensing optical circle and the demodulation unit.Last, based on the theoretical analysis, design the experimental program; use the laboratory resources to build a test platform. The test of advanced FBG accelerometer and electrical sensor under steady-state sinusoidal excitation contrast verify the system stability and reliability. Comprehensive comparative analysis of the experimental data of the two acceleration sensors to test the existence of the sensor design deficiencies. Use the software LabView to store the test date for facilitates subsequent data analysis.