摘要
为了提高稀缺的滚动轴承故障样本的利用价值,以及针对支持向量机对噪声敏感的特点,提出了基于小波阈值去噪和SVM的轴承运行状态识别的新方法。对现有故障轴承振动信号样本进行小波阈值去噪,得到相应的去噪后样本。在此基础上结合SVM的参数寻优进行SVM模型的初步建立,并将错分样本重新去噪后进行SVM模型的重建,直到惩罚因子和交叉验证的精度达到预定标准,从而实现最优模型的建立以及轴承状态的识别。但是传统的软硬阈值函数各自存在的不足制约了信号去噪和特征提取的效果,并且无法实现去噪处理的可调性,因此,首先提出了一种改进的阈值函数,并结合MATLAB仿真实验分析了其优点。最后的滚动轴承诊断实例表明,引入改进阈值函数的去噪法能有效提高样本数据利用率和SVM的抗噪与泛化能力以及滚动轴承智能诊断的可靠性。
In order to enhance the utilization value of the scarce fault samples of rolling bearing and aimed at the characteristic that support vector machines( SVM) are sensitive to noises,a new method of bearing running state recognition based on wavelet threshold de-noising and SVM was proposed. The present gathered samples of bearing's vibration signals were de-noised with wavelet threshold de-noising method,and the corresponding de-noised samples were gotten. On this basis,the SVM model was preliminarily established by combining with parameter optimization of SVM. Then,the samples which were classified incorrectly were de-noised afresh and the SVM model was reconstructed until the penalty factor and the accuracy of cross validation fixed preconcerted requirements,so as to realize the establishment of optimal SVM model and the identification of bearing running state. However,the disadvantages of the traditional soft-thresholding and hard-thresholding functions of their own restricted the effects of signal de-noising and feature extraction,then the adjustability of de-noising processing could be realized. Firstly an improved thresholding function was presented,and the advantages of this function were analyed by the MATLAB simulation experiments. The final diagnosis example of rolling bearing indicates that the introduction of the improved threshold de-noising method can effectively enhance utilization rate of sample data,the generalization capability and anti-noise property of SVM and the reliability of the intelligent diagnosis of rolling bearing.
出处
《机床与液压》
北大核心
2015年第23期187-192,共6页
Machine Tool & Hydraulics
基金
国家自然科学基金资助项目(50775157)
山西省高等学校留学回国人员科研资助项目(2011-12)
山西省基础研究项目(2012011012-1)
关键词
小波阈值去噪
阈值函数
支持向量机
滚动轴承
故障诊断
抗噪能力
利用率
Wavelet threshold de-noising
Thresholding function
SVM
Rolling bearing
Fault diagnosis
Anti-noise property
Utilization rate
