Instantaneous frequency estimation method based on Prewitt operator and PauTa detection

Abstract

The invention discloses an instantaneous frequency estimation method based on Prewitt operator and PauTa detection. According to the method, the short-time Fourier transform is adopted to transform an original signal into a time spectrogram, the Prewitt detecting algorithm is adopted to obtain multiple ridge bands, and the PauTa detection is adopted to exclude an abnormal value of each ridge band; by constructing a combined ridge band with a complete and clear edge in a superposition mode and adopting the PauTa detection to exclude abnormal values of the combined ridge band, a mean value curve of the combined ridge band is figured out, smoothing treatment is conducted on the mean value curve, confidence intervals, with a confidence level more than 95%, of the mean value curve are calculated, and then the smooth mean value curve and the confidence intervals of the curve are mapped onto target ridge lines to obtain reference lines and local searching intervals of the target ridge lines; a non-deferred cost function is adopted to extract the target ridge lines. The instantaneous frequency estimation method based on the Prewitt operator and the PauTa detection is suitable for estimation of instantaneous frequency of complex multi-component frequency conversion signals and overcomes the defects of traditional methods in estimation of instantaneous frequency of mechanical vibration signals, the accuracy degree and precision of estimation results are high, and the method is convenient to put into 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 Prewitt 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 ...

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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