Research And Design Of Fiber Bragg Grating Vibration Sensing System Based On F-P Filter

Vibration is a phenomenon which exists in nature commonly. It values a lot inpractical engineering when various problems encountered in engineering practice aresolved reasonably. With the continuous improvement and development of fiber gratingsensing technology, fiber Bragg grating sensor due to its unique advantages has become ahigh-performance methods gradually which is used in the detection of vibration signal.And it is widely used in engineering practice. When referring to the method that FBGsensors are used in detecting vibration signal, it needs demodulate the wavelength of thelight. Among the conventional demodulating methods, high frequency vibration signalcan not be demodulated, since frequencies of mechanical vibration or scanning arelimited. Therefore, in this thesis, a FBG high-frequency vibration sensing demodulationmethod based on F-P filter is raised to improve the detection frequency and accuracy ofvibration signal.In this thesis the dynamic development of vibration detection method is summarized,the fiber Bragg grating strain and temperature sensors as well as the principles andcharacteristics of vibration sensing are discussed, the importance of researching ahigh-precision and high-frequency FBG vibration sensing demodulation system isdiscussed. The specific methods of FBG high-frequency vibration sensing demodulationsystem based on F-P filter is detailed, and the optical experimental system based on thismethod is built. In VC6.0environment, the drive program of D/A card for controlling theF-P filter and the data acquisition program of A/D card are designed and compiled byC++language. The FBG sensing demodulation system is researched on experiment. Thenatural frequency of the cantilever is measured. A high-frequency vibration signal isapplied to the FBG, and it is detected and analyzed, when the frequency and amplitudechanges, the sensing system can be sensitive to change. The experimental results showthat the range of high-frequency vibration signal demodulation can be achieved to kHzunit magnitude, and the high-frequency vibration signal demodulation is achieved.