基于傅里叶级数的光栅波长信号重构及振动位移精准测量  

Fourier Series Based Grating Wavelength Signal Reconstruction and Accurate Vibration Displacement Measurement

作　　者：张翠[1] 罗睿 张寅杰 贾思凯 甘维兵[1] ZHANG Cui;LUO Rui;ZHANG Yinjie;JIA Sikai;GAN Weibing(National Engineering Research Center of Fiber Optic Sensing Technology and Networks,Wuhan University of Technology,Wuhan 430070,China;School of Information Engineering,Wuhan University of Technology,Wuhan 430070,China)

机构地区：[1]武汉理工大学光纤传感技术与网络国家工程研究中心,武汉430070 [2]武汉理工大学信息工程学院,武汉430070

出　　处：《光子学报》2024年第8期14-28,共15页Acta Photonica Sinica

基　　金：湖北省自然科学基金面上项目(No.2022CFB330);湖北省重点研发计划项目(No.2021BCA218)。

摘　　要：为实现光纤光栅传感器在多频率振动位移中的精确测量,研究了一种基于傅里叶级数的光栅波长转换。该方法将光栅波长偏移量按照振动频率分解,依据波长变化量与加速度的关系式得到振动频率分量产生的振动加速度,通过对振动加速度进行二次积分得到振动位移,对振动位移求和,实现整体振动位移的精确测量。实验结果表明,在检测单频率振动位移时,该方法的最大误差率为3.74%,基于振动主频的光栅波长转化方法的最大误差率为-4.60%。在检测双频率振动位移时,该方法的最大误差率为-8.45%,基于振动主频的光栅波长转化方法的最大误差率为-74.25%。因此,该基于傅里叶级数的光栅波长转化方法能够准确分解并重构光栅波长信号,在测量多频率振动位移时精度更高,稳定性更强。During operation of a water turbine,the vibration of its mechanical structure may reflect its operating condition.If the peak value of the vibration displacement exceeds a certain range,the water turbine may malfunction,causing serious accidents resulting in casualties and property damage.Therefore,real-time monitoring of the vibration displacement of water turbines is of great importance to ensure the safe operation of water turbines.Existing vibration displacement calculation methods do not consider the influence of vibration frequency,resulting in significant errors when measuring complex vibration displacements.This paper proposes a grating wavelength conversion method based on Fourier series.First,the wavelength variation of the fiber-optic grating sensor feedback is decomposed into multiple wavelength components containing only a single frequency according to different frequencies.Calculate the vibration acceleration generated by each wavelength component corresponding to the vibration component based on the sensitivity of the sensor.Calculate the vibration displacement generated by each vibration component by quadratic integration of the vibration acceleration.Sum these vibration displacements to obtain the total vibration displacement.Perform displacement measurement for complex vibrations.In order to improve the accuracy of vibration displacement measurement,we conducted calibration experiments on the sensitivity outside the stable operating frequency band of fiber-optic grating sensors,because only a part of the corresponding relationship between vibration frequency and sensitivity is included in the stable operating frequency band.And the corresponding relationship between vibration frequency and wavelength change in this part of the frequency was determined by segmented fitting.Two experiments were designed to compare the ability of this method to calculate vibration displacement with traditional methods.They are the simple harmonic vibration experiment and the complex vibration experiment.The harmoni

关 键 词：光纤布拉格光栅 振动位移测量 波长信号重构 傅里叶级数 机械振动 

分 类 号：TN253[电子电信—物理电子学]