小波分形技术及其在非平稳故障诊断中的应用

根据小波变换和分形理论在多尺度分析和自相似本质上的一致性，提出了小波分形技术。为了克服目前离散信号盒维数计算方法的不足，推导出了确定周期或准周期振动信号无标度区的经验公式，使盒维数的改进算法具有简单、准确和实用的特点。通过汽轮发电机组轴瓦松动故障的成功诊断案例表明，小波分形技术为非平稳故障诊断提供了一种有效的新技术。

Wavelet Fractal Technology and Its Applications to Nonstationary Fault Diagnosis

Wavelet fractal technology (WFT) is proposed according to the unity that possesses multiscale decompositions and self similarity in both wavelet transform and fractal theory. In order to overcome disadvantage of the general method calculating box dimension (BD) of discrete signals, an improved algorithm of BD is given. An empirical formula is derived for choosing scale invariant region of periodic or quasi periodic signals. Successful application has been achieved to detect looseness fault in bearing bushing of turbo generator set. The results show that WFT can provide a new effective technology to reveal nonstationary fault of mechanical equipment.