Abstract: In order to improve the precision and efficiency for fractal dimension calculation and reduce manmade influence, a technique is proposed for fractal scaleless band automatic identification. The method is based on the study of the correlation integral algorithm and the information of time series. The number of fit points was also considered. Firstly the fractal scaleless’s probable range is estimated.Then it is exactly confirmed. Finally regression significance test of lnr～lnCq? curve is made.The method was applied to analyze two aero engine’s vibration time series, which were tested in different operation conditions and different rotate speeds. Meanwhile the result was compared with the general calculation results. It shows that the method is effectual no matter how much scaleless band is and the linearity of curves is better in the scaleless band. The method is more objective, precise, simple and applicable, however sometimes the fractal scaleless band may be shrunk by it.

Key words: Correlation integral, Fault diagnose, Fractal scaleless band, Phase space reconstruction