局部特征尺度分解方法在机械振动中的应用

摘要

局部特征尺度分解（Local characteristic-scale decomposition ,简称LCD）是一种能够自适应处理非平稳非线性信号的方法。其主要思想是把一个复杂的时域信号分解为若干个内禀尺度分量（Intrinsic scale component，简称ISC）与一个残余项之和，然后再求其各个ISC分量的瞬时频率。但是利用线性变换得到的基线信号不够光滑。为此将基线分段进行三次样条插值，并设每段端点的一阶导数为零来得到基线信号的方法。经过对仿真分析，该方法具有更高的精度；而且，通过分析实测信号，进一步证明该方法的有效性。%Local characteristic-scale decomposition ( LCD) is a adaptive method of processing nonlinear and non-stationary signal. The main idea of the LCD is to decompose a complex time domain signal into several intrinsic scale component ( ISC) and a residual signal, and then to obtain the instantaneous frequency of each ISC. But baseline signal obtained by using the linear transformation is not smooth enough. In view of this, a new method of getting them by the piecewise cubic spline interpolation is proposed in this passage and the first-order derivative of each segment endpoint is set to zero. The study to the simulation signals proves the method can offer higher precision. The method effectiveness is proved in further by studying actual signals.