提出了基于信号共振稀疏分解的包络解调方法,并将其应用到轴承故障诊断中。与常规的基于频带划分的信号分解方法不同,信号共振稀疏分解方法根据信号中各成分品质因子的不同,将信号分解成高共振分量和低共振分量。当轴承出现损伤时,振动信号由以包含轴承自身振动的谐振信号、包含轴承故障信息的瞬态冲击信号以及噪声组成。谐振信号为窄带信号,具有高的品质因子,可分解为高共振分量;而瞬态冲击信号为宽带信号,具有低的品质因子,可分解为低共振分量。基于信号共振稀疏分解的包络解调方法首先利用信号共振稀疏分解方法将信号分解成高共振分量、低共振分量及残余分量,再对低共振分量进行包络解调分析,根据包络解调谱进行轴承故障诊断。算法仿真和应用实例表明该方法能有效地提取轴承故障信号中的冲击成分,凸显故障特征。
Envelope demodulation method based on resonance-based sparse signal decomposition is proposed and is applied to the fault diagnosis of roller bearings. Different from the traditional signal decomposition method based on the frequency band, resonance-based sparse signal decomposition method decomposes a signal into high and low resonance components based on the Q-factor. When a damage occurs in a roller bearing,its vibration signal is composed of harmonic one,transient impulse signal with bearing fault information and noise. The harmonic signal belongs to narrowband one and has a high Q-factor,and can be decomposed into high resonance component;while the transient impulse signal belongs to wideband one and has a low Q-factor,and can be decomposed into low resonance component. The proposed method decomposes the vibration signal of a roller bearing into high resonance component, low resonance one and residual one using resonance-based sparse signal decomposition, and the low resonance component is analyzed by envelope demodulation method, then the fault diagnosis of a bearing is carried on according to the envelope demodulation spectrum. Simulation and application examples show that the impulse can be extracted effectively from the fault vibration signal of a bearing and the feature of fault bearings can be enhanced.