CAJ | 학술논문

提纯旋转机械设备故障振动信号中的冲击特征，可以有效地实现相关故障的诊断。利用S变换适合于处理冲击特征信号的特点，提出基于 S 变换谱阈值去噪的冲击特征提取方法。先将信号进行 S 变换，得到其时频谱。考虑到此 S 变换谱为一复数矩阵，故而根据谱系数的模值大小进行阈值去噪。去噪过程中分别采用了基本的硬阈值函数和软阈值函数。对于最优阈值的估计，以所提出的改进风险函数为评价标准，利用步长迭代算法在零到系数最大模值的区间内获取。最后将去噪后的时频谱进行 S 逆变换，重构得到时域冲击特征。仿真信号与滚动轴承故障振动信号的处理结果表明，利用所获取的最优阈值，S 变换谱阈值去噪方法能够从噪声混合信号中提取出冲击特征，从而实现相关故障的诊断。
제순선전궤계설비고장진동신호중적충격특정，가이유효지실현상관고장적진단。이용S변환괄합우처리충격특정신호적특점，제출기우 S 변환보역치거조적충격특정제취방법。선장신호진행 S 변환，득도기시빈보。고필도차 S 변환보위일복수구진，고이근거보계수적모치대소진행역치거조。거조과정중분별채용료기본적경역치함수화연역치함수。대우최우역치적고계，이소제출적개진풍험함수위평개표준，이용보장질대산법재령도계수최대모치적구간내획취。최후장거조후적시빈보진행 S 역변환，중구득도시역충격특정。방진신호여곤동축승고장진동신호적처리결과표명，이용소획취적최우역치，S 변환보역치거조방법능구종조성혼합신호중제취출충격특정，종이실현상관고장적진단。
Extracting impact features from a rotating machinery fault vibration signal is significant to some fault diagnoses.Based on the fact that S-tansformation is suitable for processing signals with impact features,an effective impact feature extracting method with the threshold denoising for S-transformation spectrum was proposed.Firstly,the time-frequency spectrum of a time-domain signal was obtained using S-transformation.As the spectrum coefficients were complex numbers,the spectrum threshold denoising was performed according to the magnitude of coefficients.During denoising,both the hard and the soft threshold functions were used,respectively.Most importantly,the optimal threshold estimation was obtained between zero and the maximum modulus of the coefficients with the step iterative algorithm,and evaluated with the introduced modified risk function.Finally,the inverse S-transformation was carried out on the denoised time-frequency spectrum to reconstruct the time-domain impact features.The processing results of simulated signals and rolling bearing fault vibration signals showed that using the acquired optimal threshold,S-transformation spectrum threshold denoising method can be used to successfully extract impact features from noise mixed signals,so as to realize the related fault dignosis.