Rotor dynamic balance fault feature extraction method under keyless phase change rotating speed

Abstract

The invention discloses a rotor dynamic balance fault feature extraction method under a keyless phase change rotating speed. The method comprises the steps of carrying out band-pass filtering noise reduction processing on an acquired vibration signal; performing time-frequency analysis on the vibration signal after noise reduction processing through short-time Fourier transform to obtain time-frequency energy distribution; calculating by adopting a Sobel operator to obtain an energy gradient, and searching a target ridge line with the minimum energy gradient by adopting a dynamic programming algorithm so as to adjust the discontinuity of ridge line change caused by noise and realize accurate estimation of the instantaneous rotation frequency of the variable-rotating-speed vibration signal; and according to the extracted instantaneous rotation frequency, carrying out order tracking calculation and discrete spectrum correction on the vibration signal after noise reduction processing, and extracting the amplitude and the phase corresponding to a first-order spectrum. According to the invention, near frequency and strong noise interference can be overcome, the dynamic balance fault features of the variable-speed rotor can be accurately extracted under the condition of keyless phase signal, the hardware cost is saved, and the dynamic balance efficiency is improved.

Description

technical field [0001] The invention relates to the fields of rotor dynamic balance fault diagnosis and signal analysis and processing at variable speeds, in particular to a method for extracting rotor dynamic balance fault features at keyless phase change speeds. Background technique [0002] With the rapid development of production technology and equipment manufacturing industry, the structure of mechanical equipment has become more and more complex. Among the rotating parts of these complex equipment, the rotor is mostly used as the main working part. Rotor unbalance is gradually becoming the main cause of rotating machinery failure. Vibration signals are the most important source of information in the process of monitoring and diagnosing complex equipment. They can directly reflect the operating status of equipment and contain rich fault information. They are usually used in rotor unbalance fault diagnosis. The traditional rotor unbalance fault diagnosis method is based...

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Problems solved by technology

Chinese invention patent 201911285855.2 proposes a method for feature extraction of rotating machinery faults without a tachometer at variable speeds. This method is based on the assumption that the speed of the signal will not change in a short period of time (such as 1-4 cycles), with the help of matching pursuit method Realize the extraction of instantaneous frequency of rotating machinery with variable speed, but it is not suitable for the situation where the speed fluctuates violently, and even seriously affects the extraction accuracy of instantaneous frequency

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