Instantaneous frequency estimation method based on non-delayed cost function and t-test
A technology of cost function and instantaneous frequency, which is applied in computing, image data processing, computer components, etc., can solve the problems of low accuracy and precision, delay of one-step cost function, and inability to change with time, so as to eliminate errors , Eliminate the effect of time delay
Active Publication Date: 2019-11-01
山东中科普锐检测技术有限公司
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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 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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[0065] Examples such as figure 1 As shown, the instantaneous frequency estimation method based on non-delayed cost function and t test includes the following steps:
[0066] Step 1: Use the short-time Fourier transform algorithm to convert the signal x(k) (k=1, 2, ..., N) into a time-spectrogram, where N represents the length of the signal;
[0067] Step 2: Select a local area with a high signal-to-noise ratio from the time-spectrogram, and use the Canny detection algorithm to convert the local area into a binary image. The binary image contains multiple ridge bands; a local area refers to at least two Ridge bands, the area where the signal-to-noise ratio is greater than 80dB;
[0068] Step 3: Use the t-test algorithm to exclude outliers at the upper and lower edges of each ridge band;
[0069] Step 4: Superimpose the above-mentioned multiple ridges on one of the ridges with the most complete outline according to the kinematic proportional relationship between them to constr...
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The invention discloses an instantaneous frequency estimation method based on non-delay cost function and t test. This method uses short-time Fourier transform to convert the original signal into a time-spectrogram, uses the Canny detection algorithm to obtain multiple ridge bands, uses t-test to eliminate the outliers of each ridge band, and constructs a composite with complete and clear edges by superposition Ridge bands, use t test to exclude the outliers of the synthetic ridge bands, calculate the mean curve of the synthetic ridge bands, smooth the mean curve, calculate the confidence interval of the smooth mean curve at the 95% confidence level, and combine the smooth mean curve and its The confidence interval is mapped to the target ridge, and the reference line and local search interval of the target ridge are obtained, and the target ridge is extracted using a non-delayed cost function. The invention is suitable for estimating the instantaneous frequency of complex multi-component frequency conversion signals, overcomes the defects of the traditional method in estimating the instantaneous frequency of mechanical vibration signals, has high accuracy and precision of the estimation result, and is convenient for 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 a non-delayed cost function and a 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 an...
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IPC IPC(8): G01M13/02G01M13/00G06K9/00G06T7/11
CPCG06T7/11G01M13/00G01M13/028G06F2218/10G06F2218/04
Inventor 林近山
Owner 山东中科普锐检测技术有限公司