低信噪比矿井提升机振动信号融合去噪算法

Fusion denoising algorithm for vibration signal of mine hoist with low signal-to-noise ratio

针对矿井复杂环境下提升机振动信号非线性、低信噪比的特点,提出了一种基于总体平均经验模态分解(CEEMDAN)和自适应小波阈值的矿井提升机振动信号融合去噪算法。首先,采用CEEMDAN算法对含噪的矿井提升机振动信号进行分解,得到本征模态分量(IMF)和残差,对IMF分量进行高低频判断,采用t检验方法对该均值是否显著区别于0进行检验,趋于0的IMF分量为高频分量,显著区别于0的IMF分量为低频分量。然后,选取合适的小波基函数及分解层数,结合自适应小波阈值方法对高频IMF分量进行去噪处理。最后,将处理后的高频IMF分量和未处理的低频IMF分量与残差重构,得到融合算法去噪后的振动信号。分别采用CEEMDAN去噪算法、CEEMD-小波阈值联合去噪算法、CEEMDAN-小波阈值联合去噪算法和CEEMDAN-自适应小波阈值融合去噪算法对仿真信号进行去噪处理,结果表明:(1)CEEMDAN-自适应小波阈值融合去噪算法去噪后的信号在局部波形特征和信号峰值上与原始信号相似度较高,信号波形的一些特征得到了很好的复原,在去噪过程中很好地保留了原始信号的特征信息。(2)采用复合评价指标H作为客观评价标准,CEEMDAN-自适应小波阈值融合去噪算法的H值最小,说明融合去噪算法对于仿真信号的去噪效果要优于其他几种去噪算法的去噪效果。在黑龙江某矿正在运行的矿井提升机上进行试验,结果表明:(1)采用db4小波基函数对含噪IMF分量进行4层分解,CEEMDAN-自适应小波阈值融合去噪算法去噪后的信号比较光滑,信号的一些波形特征也得到了很好的复原,在剔除噪声的同时,最大程度上保留了原有信号的特征信息。(2)在实际矿井提升机振动信号的去噪过程中,CEEMDAN-自适应小波阈值融合去噪算法的H值最小,去噪效果最佳。

Aiming at the nonlinear and low signal-to-noise ratio characteristics of mine hoist vibration signal in complex environments,a mine hoist vibration signal fusion denoising algorithm based on complete EEMD with adaptive noise(CEEMDAN)and adaptive wavelet threshold is proposed.Firstly,the CEEMDAN algorithm is used to decompose the noisy mine hoist vibration signal to obtain the intrinsic mode component(IMF)and the residual.The IMF component is judged for high and low frequency.The t-test method is used to test whether the mean value is significantly different from 0.The IMF component which tends to 0 is the high-frequency component,and the IMF component which is significantly different from 0 is the low-frequency component.Secondly,the appropriate wavelet basis function and decomposition level are selected.The high-frequency IMF component is denoised by using the adaptive wavelet threshold method.Finally,the processed high-frequency IMF components and the unprocessed low-frequency IMF components are reconstructed with the residuals to obtain the de-noised vibration signal from the fusion algorithm.The CEEMDAN denoising method,CEEMD-wavelet threshold combined denoising method,CEEMDAN-wavelet threshold combined denoising method and CEEMDAN-adaptive wavelet threshold fusion denoising method are used to denoise the simulated signal respectively.The results show the following points.(1)The signal denoised by the CEEMDAN-adaptive wavelet threshold fusion denoising method is similar to the original signal in local waveform features and signal peak values.Some features of the signal waveform have been restored well.The feature information of the original signal has been well preserved in the process of denoising.(2)The composite evaluation index H is used as the objective evaluation standard.The H value of the CEEMDAN-adaptive wavelet threshold fusion denoising method is the smallest.This shows that the denoising effect of the fusion denoising algorithm for the simulation signal is better than that of other denoising methods.The experiment is carried out on the running mine hoist in a mine in Heilongjiang Province.The results show the following points.(1)The db4 wavelet basis function is used to decompose the noisy IMF component in four layers.The signal de-noised by CEEMDAN-adaptive wavelet threshold fusion de-noising method is smooth.Some waveform features of the signal have also been restored well.While removing the noise,the feature information of the original signal has been retained to the greatest extent.(2)In the actual mine hoist vibration signal denoising process,the CEEMDAN-adaptive wavelet threshold fusion denoising method has the smallest H value and the best denoising effect.