旋转机械故障窄带信号的循环平稳特征分析

阐述了窄带叠加正弦调幅信号的循环平稳特征,指出了窄带叠加正弦调幅信号与其对应的确定性正弦调幅信号循环矩相比,循环频率不变,仅将确定性幅值变成了随机幅值,幅值的大小和相位发生了变化;并以旋转机械中使用最为广泛的轴承故障的诊断为例,对机械故障的窄带信号循环平稳特征进行了分析;使用傅氏级数及相关分析理论,给出了周期冲击信号循环自相关函数数学表达式,得到了故障存在于内外环和滚动体上的二阶循环频率大小;最后通过实例分析证明了理论的正确性。

Cyclostationary Characteristic Analysis for Narrowband Signal of Rotation Machinery Fault

This paper addresses the cyclostationary characteristic of narrowband signals mixed by sine amplitude modulation, and a conclusion is achieved that the cyclostationary frequency is invariable and only the amplitude and phase are changed while compared with fixed signal′s cyclic moment. By the bearing fault diagnosis example, the cyclostationary characteristic of narrowband signals of machinery fault is analysed. FT and correlation theory are applied to acquire cyclic correlation algorithm of period impact signals and second-order cyclic frequency of bearing faults including the inner ring, out ring and ball. Finally the fault example is demonstrated to show the validity of this approach.