基于光功率切割算法的级联FBG光谱重叠识别研究

Research on Spectral Overlap Recognition of Cascaded Fiber Bragg Grating Based on Optical Power Cutting Algorithm

针对级联光纤布拉格光栅(FBG)传感器使用时,实际工况不确定应变可能使2个中心波长邻近的FBG光谱动态重叠,引起测试信号紊乱而无法被商用FBG解调设备软件正确解调,导致被测对象的真实应变丢失或失真问题,提出一种FBG光谱光功率切割算法。建立光功率等值线函数模型,搜索等间隔光功率等值线族与FBG光谱的交点,依据交点个数对2个具有邻近中心波长的FBG光谱重叠状态进行识别。经风电叶片交变载荷疲劳试验中2个级联FBG实测数据计算案例表明,本文提出的FBG光谱光功率切割算法能有效识别2个FBG传感器的重叠光谱,为级联FBG传感器工程应用自诊断提供了解决方案。

When using cascaded fiber Bragg grating(FBG)sensors,the uncertain strain may dynamically overlap the FBG spectra adjacent to two central wavelengths under actual working conditions,causing the test signal to be disordered and unable to be correctly demodulated by the commercial FBG demodulation equipment software,resulting in the loss or distortion of the real strain of the tested object.A FBG spectral optical power cutting algorithm is proposed and an optical power contour function model is established,Search the intersection of the equidistant optical power contour family and the FBG spectrum,and identify the overlapping states of two FBG spectra with adjacent central wavelengths according to the number of intersections.The calculation case of the measured data of two cascaded FBG sensors in the alternating load fatigue test of wind turbine blades shows that the FBG spectral optical power cutting algorithm proposed in this paper can effectively identify the overlapping spectra of two FBG sensors,and provides a solution for the self diagnosis of cascaded FBG sensors in engineering application.