基于小波降噪和Hilbert-huang变换的柴油机瞬时转速分析

Design of Transient Speed Filter for Marine Diesel Engine Based on Hilbert-huang Transform

柴油机瞬时转速信号存在大量测量噪声和环境噪声。直接使用HHT对柴油机瞬时转速信号处理时存在边缘效应和模态混叠问题,文中尝试利用小波降噪与EMD分解相结合的处理方法,根据处理前后的波形曲线和频谱分析发现,基于小波降噪和Hilbert-huang变换的柴油机瞬时转速处理可以有效消除EMD分解的边缘效应和模态混叠问题,并且能得到物理意义明确的分量。实验结果表明,该方法对于各工况下的柴油机瞬时转速都能够得到较好的处理效果,为下步基于瞬时转速的舰船柴油机故障诊断系统研制打下良好基础。

In diesel engine instantaneous speed signal there is a lot of measurement noise and ambient noise.The edge effect and modal aliasing problem of diesel engine instantaneous speed signal processing are directly used by HHT.The method of wavelet denoising and EMD decomposition is used in this paper.According to the waveforms and spectral analysis before and after the treatment,and Hilberthuang transform can effectively eliminate the edge effect and modal aliasing problem of EMD decomposition,and can get the reasonable meaning of the physical meaning.The experimental results show that this method can achieve better processing effect for the instantaneous speed of the diesel engine under each working condition,which will lay a good foundation for the development of the diesel engine fault diagnosis system based on the instantaneous speed.