基于STFT和FPO的旋转机械阶次分析

Order Analysis of Rotary Machinery Based on STFT and FPO

针对在无转速计下发动机转速难以估计的问题,采用短时傅里叶变换(short-time Fouriertransform,STFT)和快速路径优化(fast pathoptimization,FPO)相结合的方法对发动机进行转速估计,结合无转速计阶次分析方法对某客车变速箱底部振动信号进行分析。使用STFT分析振动信号,运用FPO算法从时频图中提取特征阶次所对应的瞬时频率值,计算得到发动机转速曲线,通过积分采样得到等角度间隔信号,最终得到阶次图。仿真分析和试验分析的结果表明:文中方法在提取时频图中相应的瞬时频率值有较高的精度和较好的抗噪性,能够在无转速计的情况下有效实现旋转机械振动信号的阶次分析。

To solve the problem in estimating engine speed without a tachometer,a method combined the short-time Fourier transform(STFT)with fast path optimization(FPO)was used to estimate the en⁃gine speed.And the vibration signal at the bottom of the transmission of a passenger car was analyzed by using the non-tachometer order analysis method.The vibration signal was analyzed by STFT.The in⁃stantaneous frequency value corresponding to the characteristic order was extracted from the time-fre⁃quency spectrum by FPO algorithm.The engine speed curve was calculated.Then the equal angle inter⁃val signal was obtained by integral sampling.And the order spectrum was finally obtained.The results of simulation and experimental analysis show that the method has high accuracy and good noise immuni⁃ty in extracting the corresponding instantaneous frequency values in the time-frequency spectrum,and can effectively realize the order analysis of rotary machinery vibration signals without tachometer.