机械工程学报
機械工程學報
궤계공정학보
CHINESE JOURNAL OF MECHANICAL ENGINEERING
2015年
3期
121-128
,共8页
低次故障特征阶比系数%等效转频%瞬时故障特征频率%变转速%滚动轴承%故障诊断
低次故障特徵階比繫數%等效轉頻%瞬時故障特徵頻率%變轉速%滾動軸承%故障診斷
저차고장특정계비계수%등효전빈%순시고장특정빈솔%변전속%곤동축승%고장진단
lower fault characteristic order coefficient%equivalent rotational frequency%instantaneous fault characteristic frequency%varying rotational speed%rolling bearing%fault diagnosis
基于时频表达的阶比跟踪算法能够帮助实现变转速旋转设备的故障诊断而不依靠转速计的帮助。然而，滚动轴承振动信号的时频表达却因缺少明显且易提取的转频成分使得该算法无法得到应用。为此，引入瞬时故障特征频率作为滚动轴承的等效转频，并提出基于低次故障特征阶比系数的估计算法对其进行提取。根据转频的变化范围确定基本滤波带宽并沿频率轴构造一组带通滤波器对原信号进行带通滤波。计算各带通滤波结果的包络时频谱并提取相应的等效转频趋势线。利用等效转频趋势线对相应的滤波结果进行重采样并计算故障特征阶比包络谱。将各阶比包络谱中与一、二、三次故障特征阶比相对应的幅值之和作为标准确定最优滤波带宽与相应的等效转频趋势线(瞬时故障特征频率趋势线)。利用该趋势线对原始信号进行故障相角域重采样，所得结果故障特征阶比包络谱即可用于滚动轴承的故障诊断。仿真算例和应用实例证明了该算法的有效性。
基于時頻錶達的階比跟蹤算法能夠幫助實現變轉速鏇轉設備的故障診斷而不依靠轉速計的幫助。然而，滾動軸承振動信號的時頻錶達卻因缺少明顯且易提取的轉頻成分使得該算法無法得到應用。為此，引入瞬時故障特徵頻率作為滾動軸承的等效轉頻，併提齣基于低次故障特徵階比繫數的估計算法對其進行提取。根據轉頻的變化範圍確定基本濾波帶寬併沿頻率軸構造一組帶通濾波器對原信號進行帶通濾波。計算各帶通濾波結果的包絡時頻譜併提取相應的等效轉頻趨勢線。利用等效轉頻趨勢線對相應的濾波結果進行重採樣併計算故障特徵階比包絡譜。將各階比包絡譜中與一、二、三次故障特徵階比相對應的幅值之和作為標準確定最優濾波帶寬與相應的等效轉頻趨勢線(瞬時故障特徵頻率趨勢線)。利用該趨勢線對原始信號進行故障相角域重採樣，所得結果故障特徵階比包絡譜即可用于滾動軸承的故障診斷。倣真算例和應用實例證明瞭該算法的有效性。
기우시빈표체적계비근종산법능구방조실현변전속선전설비적고장진단이불의고전속계적방조。연이，곤동축승진동신호적시빈표체각인결소명현차역제취적전빈성분사득해산법무법득도응용。위차，인입순시고장특정빈솔작위곤동축승적등효전빈，병제출기우저차고장특정계비계수적고계산법대기진행제취。근거전빈적변화범위학정기본려파대관병연빈솔축구조일조대통려파기대원신호진행대통려파。계산각대통려파결과적포락시빈보병제취상응적등효전빈추세선。이용등효전빈추세선대상응적려파결과진행중채양병계산고장특정계비포락보。장각계비포락보중여일、이、삼차고장특정계비상대응적폭치지화작위표준학정최우려파대관여상응적등효전빈추세선(순시고장특정빈솔추세선)。이용해추세선대원시신호진행고장상각역중채양，소득결과고장특정계비포락보즉가용우곤동축승적고장진단。방진산례화응용실예증명료해산법적유효성。
Extraction of the rotational frequency is the key step of employing order tracking based on the time-frequency representation (TFR) in fault diagnosis of rotational mechanical machinery under varying rotational speed the assistance of a speed sensor. However, the lack of obvious and extractable rotational frequency components in the TFR of the vibration signal of the rolling bearing will block the usage of this algorithm. As such, a new equivalent rotational frequency (ERF) of IRF, the instantaneous fault characteristic frequency (IFCF), is introduced, and a corresponding estimation algorithm based on the lower fault characteristic order coefficient is proposed to estimate this ERF. A series of band-pass filters whose frequency bands can be determined by the range of rotational frequency are constructed along the frequency axis. The ERFs of all these band-pass filtered results are then extracted from the envelope time-frequency representation of the corresponding band-pass filtered results. The fault characteristic order (FCO) envelope spectrums are calculated based on the resampled version of the band-passed filtered signal using the corresponding ERF. The lower fault characteristic order coefficient which equals to the amplitude summation of the 1st, the 2nd and the 3rd fault characteristic order is finally used to determine the best filtered band and corresponding ERF. Resampling the original vibration signal with the IFCF trend can result in the resampled signal which can be used for the final diagnosis of rolling bearing under the varying rotational speed. The effectiveness of the proposed method is validated by both simulated and experimental bearing vibration signals.
