A Method Research Of Extracting Shifts Obits Based On Signal Sparse Representation

As a kind of important graphic signs in the vibration of the rotary machine, theorbit of shaft centre-line include a large number of fault information, so the level ofpurification and identification of the orbits determines the level of fault diagnosisdirectly. Aim at that the obit contains much noise and the characters can’t be extractedcorrectly, this paper discuss about the method of purification and extractingcharacters,which will have a vital scientific significance and the project use value. Theorganization of this research is as following:Firstly, after introduce the background of the orbit studying, this paper analysis therotor vibration mechanism in detail under various fault causes. Based on theoreticalcalculation of force conditions, several mechanical models are established. In while,both time domain waveform feature and frequency spectrum feature of axis orbits wasanalyzed.Secondly, aim at that the nowadays de-noising methods are based on the usefulsignal and noise signal are in different frequencies, a method based on sparserepresentation is put forward. By using an algorithm—SALSA, the measured obit signalcan be translated into a very compact signal, which has no noise. Meanwhile, thealgorithm can be improved by optimizing the parameters. Then the effect of improvedalgorithm can be found by simulating calculation. The results proved that the improvedalgorithm has a better purification.Thirdly, based on the purified signal, the characters of the obits can be get byimproved invariant moments and Fourier descriptors. Then the obits can bedistinguished by Euclidean distance classification. The simulation results show that themethods can get the characters of the orbits and has a certain accuracy.Last, a software measurement system is developed based on the improvedalgorithm and virtual instrument technology. This system includes the purification,characters extracting and recognition. Using the system on thewater-lubricatedtransmission system for experiment, the resultsshow the methodsdiscussed in this paper have a good ability in purifying the obits. In a word, the theoretical research and experiments of this paper make an usefulattempt in the research of the orbit of shaft, which has a scientific significance andengineering valuefor the condition monitoring and fault diagnosis of the rotor system.