基于EMD与峭度滤波的煤岩界面识别

Application of Filtering Method Based on EMD and Kurtosis in Coal-Rock Interface Recognition

煤岩界面识别问题一直是制约放煤自动化发展的一项关键问题,液压支架尾梁振动信号分析法是近年来发展较快的一种有效方法。该方法中煤和矸石信号在频域内存在差异是非常有用的信息,但因系统低频干扰较多且两种信号差异微弱,无法直接提取使用。通过对振动信号使用经验模态分解(empirical mode decomposition,简称EMD)得到多个固有模态分量(intrinsic mode function,简称IMF);以峭度为准则,选取煤和矸石差异最大的通道对信号重新合成;使用Hilbert边际谱分析煤、矸石的频域范围,以矸石频域特征区域求取带通滤波最优截止频率;对合成后的信号进行滤波。实验结果表明,该方法能够减少信号低频干扰、突出较高频成分,使煤与系统干扰的低频信号视为常态被屏蔽,而混入煤中的矸石较高频信号能够被及时识别,实现了煤岩界面识别的目的。

A new method based on empirical mode decomposition(EMD)and kurtosis is used to recognize the coal-rock interface.Vibration signals of the rock and coal are obtained on the hydraulic support tail beam.The signals are first decomposed using EMD to obtain the intrinsic mode functions(IMFs).The IMFs can be used to decompose the signals to distinguish between rock signals and coal signals by kurtosis.In this process,the low frequency interference is reduced and the high-frequency interference is highlighted.The frequency ranges of coal and rock can be analyzed by Hilbert marginal spectrum of the IMFs.The optimal cut-off frequency of the band pass filter can be found according to the frequency domain characteristics of rock.Finally,the vibration signals are processed by the filter.The results show that the coal signal and the interference signal are shielded,and the rock signal mixed in the coal signal can be recognized.Thus,the coal-rock interface is recognized.