Instantaneous Frequency Estimation Method Based on Non-Delayed Cost Function and Grubbs Test

Abstract

The invention displays an instantaneous frequency estimation method based on a non-deferred cost function and the Grubbs verification. The method comprises the steps that an original signal is converted into a time-frequency spectrogram by using the short-time Fourier transform, a plurality of ridged bands are obtained by using the Canny detection algorithm, the abnormal value of each ridged band is excluded through the Grubbs verification, and one synthesized ridged band which has a complete and clear edge is built through superposition; the abnormal value of the synthesized ridged band is excluded through the Grubbs verification, and a mean value curve of the synthesized ridged band is calculated; the mean value curve is subjected to smoothing processing, and the confidence interval of the smooth mean value curve at a confidence level of 95% is calculated; the smooth mean value curve and the confidence interval of the smooth mean value curve are mapped to a target ridged line, a reference line and a local search interval of the target ridged line are obtained, and the target ridged line is extracted by using the non-deferred cost function. The instantaneous frequency estimation method is suitable for estimating the instantaneous frequency of a complex multi-component variable frequency signal, the defect of a traditional method in the instantaneous frequency estimation of a mechanical vibration signal is overcome, the estimation result is high in accuracy and precision, and engineering application is facilitated.

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 a non-delayed cost function and a Grubbs 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 search range is set arbitrarily according to experience, and the...

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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 search 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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