No-time-mark order tracking method based on self-demodulation transform

Abstract

The invention provides a no-time-mark order tracking method based on self-demodulation transform, comprising the following steps of: firstly, adsorbing an accelerated speed or speed sensor on a tested rotary machine and collecting a vibration signal; utilizing fractional order Fourier transform to carry out time frequency rotation on the vibration signal and projecting to a frequency axis; searching a corresponding Fourier transform order alpha obtained by projecting the extreme great value of a characteristic frequency component; then extracting a stable projection amount of the characteristic frequency component by adopting a band-pass filtering method; carrying out alpha order fraction Fourier transform to obtain an engaged frequency component; then carrying out Hilbert transform to obtain an instantaneous phase of the engaged frequency component; and finally, utilizing the instantaneous phase to carry out the self-demodulation transform on the original vibration signal to obtain an order spectrum of rotary equipment, so as to finish the no-time-mark order tracking. According to the no-time-mark order tracking method based on the self-demodulation transform, the dependence on a time mark can be get rid, so that the no-time-mark order tracking method not only can be suitable for a weak rotary speed fluctuation condition, but also can be suitable for online of the rotary machine under a large rotary speed fluctuation condition of starting and stopping the machine; and the real-time order tracking is realized.

Description

technical field [0001] The invention belongs to the field of fault diagnosis and control of rotating machinery, in particular to a time-scale-free order tracking method based on self-demodulation transformation. Background technique [0002] Order tracking is the most commonly used analysis method in the fault diagnosis of rotating machinery, and it is also the key technology to solve the fault diagnosis of rotating machinery under the condition of rotational speed fluctuation. In essence, the order tracking method converts the vibration information or sound signal of the rotating machinery from the sampling sequence of equal time sampling to the sampling sequence of equal angle, so as to effectively suppress the influence of rotational speed fluctuation on spectrum analysis and fault diagnosis. [0003] The core problem of order tracking is how to accurately extract the angle domain information of the rotating machinery to realize the angle domain resampling of the vibratio...

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Problems solved by technology

[0004] Patent application numbers 201110169763.5 and 201120172140.9 respectively provide the implementation method of order tracking and corresponding hardware devices, but both of the above two patents require time scale signals, that is, speed sensors, and patent application number 201110026078.7 proposes An order tracking method that uses transmission ratio parameters to generate analog pulses and resamples vibration signals at equal angles, but this method still needs to be equipped with a speed sensor at the high-speed shaft end

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