Instantaneous frequency estimation method based on LoG operator and PauTa test

Abstract

The invention discloses an instantaneous frequency estimation method based on an LoG operator and a PauTa test. According to the method, an original signal is transformed into a time-frequency spectrogram based on short-time Fourier transform; a plurality of ridge bands are obtained according to a LoG detection algorithm; with PauTa testing, an abnormal value of each ridge band is removed; superposition is carried out to construct a synthesis ridge band with the complete and clear edge; an abnormal value of the synthesis ridge band is eliminated by PauTa testing; a mean value curve of the synthesis ridge band is calculated, smoothing processing is carried out on the mean value curve, and a confidence interval of the smooth mean value curve at the 95% of confidence level is calculated; the smooth mean value curve and the confidence interval are mapped to a target ridge line to obtain a reference line and a local searching zone of the target ridge line; and the target ridge line is extracted by using a non-delay cost function. The instantaneous frequency estimation method is suitable for estimating an instantaneous frequency of a complicated multi-component variable-frequency signal; defects in instantaneous frequency estimation of a mechanical vibration signal according to the traditional method are overcome; the accuracy and precision of the estimation result are high; and the method is convenient to 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 LoG 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 f...

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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