基于LOMS-STFRFT高精度识别时变结构非平稳响应信号的瞬时频率  

High-accuracy identification for instantaneous frequency of non⁃stationary response signals from time⁃varying structures based on LOMS-STFRFT

作　　者：刘景良 戴逸宸 郑文婷 廖飞宇 LIU Jingliang;DAI Yichen;ZHENG Wenting;LIAO Feiyu(School of Transportation and Civil Engineering,Fujian Agriculture and Forestry University,Fuzhou 350108,China;College of Civil Engineering,Fujian University of Technology,Fuzhou 350118,China)

机构地区：[1]福建农林大学交通与土木工程学院,福建福州350108 [2]福建理工大学土木工程学院,福建福州350118

出　　处：《振动工程学报》2025年第4期750-760,共11页Journal of Vibration Engineering

基　　金：国家自然科学基金青年科学基金项目(51608122);中央引导地方科技发展专项(2022L3007);福建省自然科学基金面上项目(2020J01581,2024J01423);福建省住房和城乡建设行业科技研究开发计划项目(2022-K-266);福建农林大学科技创新专项基金项目(KFB24050A)。

摘　　要：为提高时变结构非平稳响应信号的瞬时频率识别精度,提出一种局部优化多重同步挤压⁃短时分数阶傅里叶变换(locally optimized multi⁃synchrosqueezing⁃short time fractional Fourier transform,LOMS⁃STFRFT)。该算法对短时分数阶傅里叶变换(short time fractional Fourier transform,STFRFT)进行局部旋转参数的优化选取,通过STFRFT得到时频分布投影在分数域上的时频系数矩阵;对时频系数矩阵进行瞬时频率估计和多次迭代;采用多重同步挤压算子对时频系数矩阵进行重排并通过局部模极大值法提取瞬时频率曲线。通过一个多分量信号数值算例和一个线性时变拉索试验验证了所提方法的精确性。研究结果表明:相比传统的多重同步挤压算法,LOMS⁃STFRFT针对时变结构非平稳信号的瞬时频率识别效果更佳。To enhance the accuracy of instantaneous frequency(IF)identification for non-stationary response signals of time-varying structures,a locally optimized multi-synchrosqueezing-short time fractional Fourier transform(LOMS-STFRFT)algorithm is proposed in this paper.Firstly,the local rotation parameters of the short time fractional Fourier transform(STFRFT)are optimally selected in this method.Subsequently,the time-frequency coefficient matrix projected to the fractional domain is obtained through STFRFT.After that,IF estimation and multiple iterations are performed on the time-frequency coefficient matrix.The time-frequency coefficient matrix is reassigned by the multi-synchrosqueezing operator,and IF curves are then extracted via the local mode maxima method.The accuracy of the proposed method is validated through a numerical example of a multi-component signal and a linearly time-varying cable test.The results demonstrate that the proposed LOMS-STFRFT algorithm behaves better than traditional multi-synchrosqueezing transform on IF identification of non-stationary signals from time-varying structures.

关 键 词：时变结构 局部优化 短时分数阶傅里叶变换 多重同步挤压变换 瞬时频率 

分 类 号：TU311.3[建筑科学—结构工程] TN911.6[电子电信—通信与信息系统]