轮对升降速工况下短信号拼接定速信号的方法  

Method of Splicing Constant Speed Signals with Short Signals During Wheelset Acceleration and Deceleration

作　　者：张伟[1] 董大伟[1] 黄燕 闫兵[1] 华春蓉[1] 吕路梅 宋世哲 ZHANG Wei;DONG Dawei;HUANG Yan;YAN Bing;HUA Chunrong;LYU Lumei;SONG Shizhe(School of Mechanical Engineering,Southwest Jiaotong University,Chengdu 610031,China)

机构地区：[1]西南交通大学机械工程学院,四川成都610031

出　　处：《西南交通大学学报》2024年第6期1346-1356,共11页Journal of Southwest Jiaotong University

基　　金：国家自然科学基金项目(51875482)。

摘　　要：列车轮对的特征值与转速密切相关,进行轮对故障定量分析时需要采集某转速下一定长度的信号,而实际工作于变速工况的系统难以方便获得该信号,为满足定量分析的要求,提出一种不需要转速计的信号重构方法,该方法利用升降速工况下的短信号片段拼接成指定转速下的定速信号.首先,采用STFT(short-time Fourier transform)峰值搜索方法获取转速曲线,并提取通过指定转速的多个信号片段;其次,将信号片段转换成角域信号,并通过互功率谱密度确定信号间的相位差,根据相位差和前信号的长度,得到信号间的拼接位置,并采用插值和融合技术保证拼接信号的连续性;最后,将拼接得到的角域信号恢复成时域信号.经与轮对结构相似的转子实验台实验验证:某裂纹轴在升降速过程中,使用本方法获得的各转速拼接信号频谱和实验获得的定速信号频谱高度接近,其中15.0 Hz拼接信号与定速信号1x、3x值(1x和3x表示转速的1倍频和3倍频)的相对误差仅为0.9%、1.0%,将待拼接信号加入噪声且缩短到1.5个周期后,拼接相位误差不超过10°.The characteristic value of train wheelsets is closely related to the speed,and the quantitative analysis of wheelset faults requires signals with a certain length collected at a certain speed.However,such a signal is difficult to be obtained by the system working in the variable speed condition.Therefore,a signal reconstruction method that did not require any velocimeters was proposed to realize the above quantitative analysis.This method used short signal segments to splice the constant speed signals under the acceleration and deceleration conditions.Firstly,a short-time Fourier transform(STFT)peak search method was adopted to obtain the speed curve and extract multiple signal segments passing through a specified speed.Secondly,the signal segments were converted into an angular domain signal,and the phase difference between signals was determined by cross-power spectra density(CPSD).Then,according to the phase difference and the length of the front signal,the splicing position of signals was obtained,and interpolation and fusion techniques were used to ensure the continuity of spliced signals.Finally,the spliced angular domain signal was resampled into the time domain signal.A rotor test bench with a similar wheelset structure has verified that during acceleration and deceleration of a cracked shaft,the frequency spectrums of the spliced signals of each speed obtained by this method are highly close to the frequency spectrums of the constant speed signals obtained by the experiment.The relative errors of the 1x and 3x values between the spliced signal of 15.0 Hz and the constant speed signal are only 0.9% and 1.0%, respectively. After adding noise to the signals to be spliced and shortening them to 1.5 cycles, the splicing phase error does not exceed 10°.

关 键 词：定速信号 升降速工况 角域信号 互功率谱密度 转速计 信号重构 

分 类 号：TH701[机械工程—仪器科学与技术] TN911.7[机械工程—精密仪器及机械]