Instantaneous frequency estimation method based on Sobel operator and PauTa examination

Abstract

The invention discloses an instantaneous frequency estimation method based on a Sobel operator and a PauTa examination. The method comprises steps of using the short-time Fourier transform to convert an original signal into a time frequency spectrogram; using the Sobel detection algorithm to acquire multiple ridge belts; using the PauTa examination to exclude an abnormal value of each ridge belt; constructing a synthesized ridge belt with a complete clear edge through superposition; using the PauTa examination to exclude an abnormal value of the synthesized ridge belt; calculating a mean curve of the synthesized ridge belt; carrying out smoothing processing on the mean curve; calculating the confidence interval of the smooth mean curve at the 95% of confidence level; mapping the smooth mean curve and the confidence interval thereof to a target ridge line to obtain a reference line and a local searching interval of the target ridge line; and using a non-delay cost function to extract the target ridge line. According to the invention, the method is suitable for estimation of instantaneous frequency of complex multi-component variable frequency signals; defects in estimation of the instantaneous frequency of mechanical vibration signals in the prior art are overcome; accuracy and precision of estimation results are high; and the method is easily used in engineering application.

Description

technical field [0001] The invention relates to the field of state monitoring and fault diagnosis of rotating machinery, in particular to an instantaneous frequency estimation method based on Sobel operator and PauTa test. Background technique [0002] Due to the complexity of the working environment, rotating machinery often works under variable speed conditions. Instantaneous frequency estimation is an important prerequisite for evaluating the operating state and fault diagnosis of rotating machinery. The most commonly used instantaneous frequency estimation method is the one-step cost function method. The one-step cost function method can search for ridge points in the local frequency range, but the center point of the local frequency range depends on the position of the previous ridge point, which leads to a delay in the one-step cost function. In addition, the width of the local frequency range is set arbitrarily according to experience, and the width at any moment is...

AI Technical Summary

Problems solved by technology

The one-step cost function method can search for ridge points in the local frequency range, but the center point of the local frequency range depends on the position of the previous ridge point, which leads to a delay in the one-step cost function

In addition, the width of the local frequency range is set arbitrarily based on experience, and the width at any moment is fixed and cannot change with time, which leads to a lack of sufficient adaptability of the one-step cost function

The above defects lead to the low accuracy and precision of the one-step cost function method in estimating the instantaneous frequency

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