Research On Holospectrum Based On Phase Difference Correction

Holospectrum is a novel technology ,which is developed from fault diagnosis of mechanical equipment ,especially large rotating machinery. Vibration signal analysis based on FFT can basically meet the need of usual fault signature abstraction and fault analysis, but can not meet the need of accurate diagnosis and complicated fault diagnosis because of not utilizing the phase information of vibration signal affectively. Holospectrum is just developed under this condition. Making full use of the amplitude, frequency and phase information of the horizontal and vertical channels of one or several sections, therefore, Holospectrum technology can identify and diagnose the concealed fault signature more accurately than general methods. The Holospectrum for vibration signal of rotating machinery is set to the research object and the accuracy is improved.Kinds of discrete spectrum correction technologies home and abroad are compared to find its advantages and disadvantages. The principle, methods and the realization process of the ratio of discrete spectrum correction, the energy center of gravity correction, the FFT+FT spectrum zoom and several spectrum correction based on phase difference are introduced.Researching results demonstrates that the phase difference correction method based on two consecutive signals has a better accuracy , especially the accuracy of phase correction, under the noisy environment compared to the ratio of discrete spectrum correction, especially in the accuracy of phase correction. On this basis, the holospectrum based on phase difference correction of two consecutive signals is proposed, combining with the characteristics of those spectrum correction methods, it is short for the holospectrum based on phase difference correction in the follows.The holospectrum based on phase difference correction is researched and implemented. The essence of The holospectrum based on phase difference correction is to reflect the information of the vibration signal which are from the two vertical channels of the same section of the rotary machine's rotor. It is based on the Fourier algorithm and describes the rotor'vibration behaviors under different frequency using a series of synthesized ellipses. It gets the amplitude, frequency and phase of vibration signal accurately, which are acquired freely, using the phase difference spectrum correction, and then integrates the amplitude, frequency and phase from the same section of the rotor. The principle, arithmetic step and implementing process of the holospectrum based on phase difference correction is introduced in detail. Simulations and local experiments demonstrates that the holospectrum based on phase difference correction propose in this thesis is correct and valid.Base on the above researches, a holospectrum analysis system for rotating machinery is developed using the object-oriented programming language VC + +. The system includes the modules of data acquiring, time-domain analysis, frequency-domain analysis , spectrum correction, 2-D holospectrum, 3-D holospectrum, holospectrum fall , axis orbit shape based on holospectrum and so on. The local experiments demonstrate that the holospectrum analysis system for rotating machinery developed in this thesis has correct functions and gets good practical engineering value.