应用故障特征指标相对比值的低转速下编码器信号太阳轮故障特征提取

Encoder Signal Feature Extraction of Sun Gear Fault at Low Speed Using Relative Ratio of Fault Feature Index

针对低转速下太阳轮齿根裂纹故障编码器信号特征阶次提取困难的问题,本文提出了一种基于故障特征指标相对比值的特征提取检测方法。首先,将获得的编码器信号通过向前差分处理成瞬时角速度(IAS)信号,按照1/3-二叉树对得到的IAS信号进行子频带划分;其次,对各窄带信号进行包络分析,分别求取正常和故障状态下的IAS信号各子频带的谐波显著性指标(HSI),由此可计算得到其相对比值r;再次,利用r值选取包含故障信息丰富的频带;最后,对处理后的信号在选择的子频带处进行带通滤波,并在提取包络后进行谱分析,提取故障特征。对太阳轮齿根裂纹故障的实测编码器信号进行分析,验证了该方法能有效提取太阳轮故障的特征。

Aiming at the difficulty of extracting the encoder signal feature order of the sun gear with root crack at low speed,a feature extraction detection method is proposed based on the difference of the fault feature index in this paper.First,the obtained encoder signal is processed into an instantaneous angular speed(IAS)signal through forward difference,and the obtained IAS signal is divided into subbands according to the 1/3-binary tree.Then,the envelope analysis of each narrowband signal is carried out,and the harmonic significance index(HSI)of each subband of IAS signal in normal and fault states is obtained respectively,from which the relative ratio r can be calculated.And,the value of r is used to select the frequency band with rich fault information.Finally,the processed signal is filtered in the selected frequency band,and the spectrum analysis is performed after the envelope is extracted to extract the fault features.The analysis of the measured encoder signal of the sun gear with root crack fault shows that the method can effectively extract the features of the sun gear faults.