Instantaneous frequency estimation method based on Sobel operator and t inspection

Abstract

The invention discloses an instantaneous frequency estimation method based on a Sobel operator and t inspection. The method comprises the steps that short-time Fourier transform is adopted for converting original signals into a time-frequency spectrogram, multiple ridge belts are obtained through a Sobel detection algorithm, t inspection is adopted for excluding an abnormal value of each ridge belt, a synthetic ridge belt with the complete and clear edge is built through superposition, t inspection is adopted for excluding an abnormal value of the synthetic ridge belt, a mean value curve of the synthetic ridge belt is calculated, smoothing is conducted on the mean value curve, a confidence interval of the smooth mean value curve at the 95% confidence level is calculated, the smooth mean value curve and the confidence interval thereof are mapped to a target ridge line, a reference line of the target ridge line and a local searching region are obtained, and the target ridge line is extracted by adopting a non-delayed cost function. The method is suitable for estimating the instantaneous frequency of complex multicomponent frequency conversion signals, the defects of a traditional method in mechanical vibration signal instantaneous frequency estimation are overcome, the accuracy and precision of the estimated result are high, and engineering application is convenient to achieve.

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 t 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 fix...

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 arb

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