【摘要】 为解决经验模式分解(empirical mode decomposition,简称EMD)法在分解过程中产生的端点效应,提出了基于余弦函数窗的端点效应处理方法。首先,定义在余弦函数窗的中部窗函数幅值为1,而在窗的两端幅值根据余弦函数缩减;然后,将窗函数和待处理信号相乘,使待处理信号两端的幅值将按余弦函数缩减,而信号中部的数据不受影响;最后,对经加窗处理的信号做EMD分解,使分解过程中的端点效应被控制在信号两端,而信号中部的数据就可得到较好的分解结果。经分析表明,该方法可有效地抑制EMD分解中的端点效应,并可用于转子系统摩擦故障诊断。更多还原

【Abstract】 In order to solve the boundary distortion problem in the empirical mode decomposition (EMD) method,a novel boundary processing method using a cosine window is proposed.The cosine window is firstly defined that its values equal to 1 in middle of the window and reduce according to the laws of cosine/sine functions in both ends.Secondly,the analyzed signal is preprocessed by multiplying with the defined window,so that the amplitudes of the signal remain in middle and reduce in both ends.Lastly,EMD method is used to analyze the preprocessed signal.With the proposed method,the boundary distortion can be controlled in ends of the signal and the middle component can be correctly decomposed.The results show that the proposed method can effectively decrease the boundary distortion of EMD and is useful in friction fault diagnosis of rotor system.更多还原