小波阈值去噪在深小孔钻削声发射信号处理中的应用

Application of wavelet threshold de-noising method in signal processing of deep small hole drilling acoustic emission

深小孔钻削声发射信号中往往夹杂着大量噪声信号,能否有效去除这些噪声对后续利用声发射信号实现钻头状态的在线监测具有重要意义。针对深小孔钻削声发射信号中存在噪声的问题,文章采用了小波阈值法进行去噪,并详细讨论了小波阈值去噪过程中各参数的选定方法和最优选取原则。对深小孔钻削声发射信号进行去噪对比实验,结果表明:在选取4层小波分解、Sym6小波基函数、rigrsure阈值以及改进的渐进半软阈值函数去噪时,获得的信号的信噪比最大为23.6168,均方根值最小为0.1128。说明其有效去除了声发射信号中的噪声,同时又很好地保存了信号的完整度,避免信号失真,显著改善了去噪效果。

Deep small hole drilling acoustic emission signals are often mixed with a large number of noise signals,therefore,whether these noise signals could be eliminated effectively has great significance in monitoring the drill condition online through acoustic emission signals.Considering the problem of the existence of noise in deep small hole drilling acoustic emission signals,wavelet threshold de-noising method was used for signal de-noising in this paper.Selection methods and optimal selection principles of each parameter in wavelet threshold de-noising method were discussed in detail as well.And de-noising comparison experiments of deep small hole drilling acoustic emission signals were carried out,whose results show that the maximum value of SNR can reach 23.616 8 and the minimum value of RMSE can reach 0.112 8 when the 4-layer wavelet decomposition,the Sym6 wavelet basis function,the rigrsure threshold,and the progressive semi-soft threshold function are selected in the process of de-noising.Noise in acoustic emission signals can be removed effectively,and the integrity of the signal can be well preserved to avoid signal distortion in this condition,which can improve the de-noising effect significantly.