JPH08188932A - Method and device for evaluating fiber - Google Patents

Abstract

PURPOSE: To accurately and quantitatively evaluate the unevenness of a yarn such as a spun yarn by subjecting a yarn unevenness signal to a spectrum analysis and subsequently evaluating the yarn with the data of the spectrum analysis and with the average value of spectrum strengths in an arbitrary wavelength region. CONSTITUTION: A yarn unevenness signal from a yarn unevenness detector 7 comprising a light-emitting diode and a phototransistor is inputted into a yarn-evaluating device 20. The yarn unevenness signal weighed with a window such as a time window is computed with a Fourier transformer 22 and subsequently judged with a peak shape-judging means 25 and a peak ratio-judging means 26 through a moving average computing means 24. The judgment result is outputted on a display means 21. An average value in an arbitrary frequency region in an examination range is determined. The unevenness of the yarn can be judged with the determined average value data and with the data of the spectrum analysis, and the extent of the yarn unevenness to the arbitrary peak can be judged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for evaluating yarn spun by an air spinning machine or the like.

[0002]

2. Description of the Related Art In a spinning machine, for example, an air spinning machine, a sliver is drafted by a back roller, an apron, and a front roller and twisted by a swirling flow in an air spinning nozzle. After that, it is wound into a package. After the delivery roller, a monitor called a slab catcher composed of a light emitting diode and a phototransistor is provided to detect the yarn unevenness.

Conventionally, in detecting yarn unevenness by a slab catcher, the signal from the phototransistor is A / D converted, the digitized signal is spectrally analyzed by a Fourier transformer, and the calculation result is integrated for each frequency component. However, when the power spectrum intensity in a specific frequency band exceeds the set level, it is determined to be defective, and at the same time, based on the frequency determined to be defective, each roller is associated with a roller having its own number of revolutions. We try to determine the cause of defects.

7 to 9 show power spectra when the yarn unevenness signal is Fourier-transformed with a predetermined resolution from a direct current component (DC) having a frequency of 0 Hz to 10 Hz.

In this power spectrum, it can be seen that the spectrum intensity is uniform in FIG. 9 and is normal without yarn unevenness, and in FIG. 7, the level (L) exceeds the set level (L) at the frequency (p). Therefore, from this frequency (p), it is possible to determine which roller is caused by the peripheral speed of the back roller described above.

[0006]

However, the defect setting in the yarn unevenness detection described above is detected only when the spectral intensity exceeds a certain level (L), and as shown in FIG. Even if the value is less than or equal to the level, if there is a change in the overall level, there is a problem that it is not possible to quantitatively evaluate the long-period tendency of the yarn unevenness and the degree of the yarn unevenness relative to the average value.

Since such yarn unevenness changes periodically even if it does not exceed the above level, when the yarn is subsequently made into a cloth by a loom or a knitting machine, it appears as a striped pattern on the cloth.

Further, even when the level is exceeded, there is a problem that it is not possible to determine how bad the peak is with respect to the average value of the yarn unevenness. Therefore, the object of the present invention is to solve the above-mentioned problems, It is an object of the present invention to provide a yarn evaluation method and device capable of quantitatively evaluating unevenness.

[0009]

In order to achieve the above object, the invention of claim 1 spectrally analyzes the yarn unevenness signal, averages the analyzed spectral intensities in an arbitrary wavelength bandwidth, and averages them. Is a yarn evaluation method for evaluating a yarn on the basis of the above data and analyzed spectrum data.

According to a second aspect of the present invention, the peak ratio is obtained from the peak detected in the power spectrum data and the average value of the peaks, and it is determined that the time period irregularity occurs when the peak ratio exceeds the allowable value. It is the yarn evaluation method described in 1.

According to a third aspect of the present invention, the average value is obtained by excluding an arbitrary number of spectral intensity values close to the maximum value and the minimum value among the spectral intensity values in the wavelength band for which the average value is obtained. Or the yarn evaluation method described in 2.

According to a fourth aspect of the present invention, a yarn unevenness detecting device for detecting a yarn unevenness signal of a spun yarn, a Fourier transformer for spectrally analyzing the yarn unevenness signal from the yarn unevenness detecting device,
An average value calculating means for obtaining an average value from an operation signal from the Fourier transformer, a peak ratio determining means for determining a peak ratio from the average value from the average value calculating means and the spectrum intensity value from the Fourier transformer, and a peak A yarn evaluation apparatus comprising: a cycle irregularity generation determining means for determining that a cycle irregularity has occurred when a ratio exceeds an allowable value.

[0013]

According to the above-mentioned structure, in the evaluation of the spectrum-analyzed data, conventionally, the frequency value exceeding a certain level was detected in the frequency range within the investigation range. By obtaining the average value in an arbitrary frequency bandwidth and determining the average value data and the spectrum-analyzed data together, the degree of yarn unevenness with respect to a specific peak can be known, and this allows accurate yarn Can be evaluated.

Further, in obtaining the average value, by removing an arbitrary number of pieces of data of the maximum value and the minimum value, a more accurate peak ratio is obtained according to the width of the detected peak and the steepness of the peak. be able to.

[0015]

An embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

First, the air spinning machine will be described with reference to FIGS.

In FIG. 5, reference numeral 1 is an air spinning nozzle, and the sliver S drafted by the back roller 2, the apron 3 and the front roller 4 is introduced into the nozzle 1 and twisted by an air jet.

The yarn Y produced by passing through the nozzle 1 is taken up by the take-up package P via the delivery roller 5.

Immediately after the delivery roller 5, as shown in FIG. 6, a yarn unevenness detecting device 7 including a light emitting diode 8 and a phototransistor 9 is provided.
The LED light from the light is received by the phototransistor 9 through the yarn Y, which is converted into the voltage signal ES (that is, the voltage signal ES ′ is a signal corresponding to the thickness of the yarn Y) and the A / D converter 10 is also included. At, for example, it is converted into a digital signal of 256 gradations.

In FIG. 1, 7 is a yarn unevenness detecting device including the AD converter shown in FIG. 6, and the yarn unevenness signal from this yarn unevenness detecting device is input to the yarn evaluation device 20 of the present invention, and the yarn is evaluated. The unevenness state is displayed on the display means 21.

The yarn unevenness signal of the yarn unevenness detecting device 7 is weighted by a window such as a time window (not shown) and sent to the Fourier transformer 22 for calculation. The resolution of the Fourier transformer 22 is, for example, the survey frequency range (0 to
10 Hz), the calculation data as a power spectrum of 400 points can be obtained in steps of 0.025 Hz.

This operation data is used for the comparator 2 as in the conventional case.
The calculated data may be sent to the moving average value calculating means 24 in the present invention, though the result may be displayed on the display means 21.

The moving average value calculating means 24 obtains an average value of an arbitrary number of operation data sequentially sent, and also obtains a moving average value for each sequential data.

The peak shape determining means 25 determines the peak shape in the survey frequency range from the moving average data sent from the moving average value calculating means 24, and the peak ratio determining means 26 determines the peak ratio with respect to the average value. judge. The peak shape determining means 25 and the peak ratio determining means 26 are
The judgment result is output to the display means 21.

Next, the moving average value calculating means 24, the peak shape judging means 25 and the peak ratio judging means 26 will be described.

First, the power spectrum data from the Fourier transformer 22 is the calculation data described with reference to FIGS. 7 to 9, and the moving average value calculating means 24 has the power spectrum data of 400 points in steps of 0.025 Hz. Will be sent. At this time, as shown in FIG. 3, for example, when a moving average value at a point p is obtained, a moving average range M including an arbitrary sampling number before and after that is set, and the average value of the spectrum data of the range M is set to z. The average value z is determined as the moving average value at the point p, and the same is applied to 0.025 Hz.
The moving average value of each point is calculated in steps.

When obtaining this moving average value, the moving average value calculating means 24 obtains the average value c of the data in the range M excluding the maximum value a and the minimum value b, and calculates the moving average. Alternatively, the moving average value may be obtained by excluding data of a predetermined value close to the maximum value a and the minimum value c depending on the peak ratio to be detected, as the value z.

Next, the peak shape determining means 25 will be described with reference to FIG.

The power spectrum data from the Fourier transformer 22 changes minutely as shown by the solid line n in FIG. 4, but there is little change as shown by the dotted line m by taking the moving average value. Data (waveform) is obtained.

The peak shape determining means 25 determines whether or not yarn unevenness has occurred from the average value (dotted line m) in the survey frequency range (for example, 0 to 10 Hz) as follows.
That is, first, for a certain point y, the difference between the power spectrum value Y of the point y and the power spectrum values X and Z of the points (frequency) x and z spaced a predetermined distance from the point y are obtained. . Next, the ratio to the average value (AVE) in the survey frequency range, that is, the mount ratio is calculated by the following equation.

Mount ratio = {(Y-X) + (Y-Z)}
÷ (2 × AVE) × 100 [%] Then, such a mount ratio is obtained for all points in the survey frequency range, the maximum value is compared with a preset allowable value, and if the maximum value exceeds the allowable value, It is determined that yarn unevenness has occurred. By doing so, it is possible to detect and accurately determine a smooth peak having a width as shown in FIG. 4, which cannot be detected by the peak ratio determining means 26 described below.

Next, the peak ratio determining means 2 will be described with reference to FIG.
6 will be described.

The peak ratio judging means 26 judges from the average value (dotted line m) and the power spectrum value (solid line n) whether or not yarn unevenness has occurred as follows. That is, first, the ratio between the power spectrum value Y at a certain point and the average value X at that point, that is, the peak ratio is obtained by the following formula.

Peak ratio = (Y / X) × 100 [%] Next, such a peak ratio is obtained also for all points in the survey frequency range, and the maximum value thereof is set to a preset allowable value (peak cage shape determining means 25). If the maximum value exceeds the allowable value, it is determined that there is unevenness in the cycle. Then, the wavelength and intensity (peak ratio) of the unevenness are displayed, and the spinning of the weight is stopped. By doing so, a steep peak as shown in FIG. 2 can be detected and accurately determined. It should be noted that by removing more of the data to be sampled that are close to the maximum and minimum values, and obtaining the moving average value so that the tendency of the average value without failing the peak value can be reliably obtained, a more accurate The peak ratio can be calculated.

In this way, the yarn can be comprehensively evaluated by the data exceeding the level from the comparator 23, the mount ratio from the peak shape judging means 25, and the peak ratio from the peak ratio judging means 26. Become.

[0036]

In summary, according to the present invention, in the evaluation of spectrum-analyzed data, conventionally, a frequency value exceeding a certain level was detected in the frequencies in the survey range, but according to the present invention, The average value is obtained in any frequency bandwidth within the survey range, and the average value data and the spectrally analyzed data are combined to determine the degree of yarn unevenness for a specific peak. It is possible to evaluate various threads. In particular, it is suitable for detecting long-period unevenness with a wavelength of 50 cm to 10 m.

[Brief description of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention.

FIG. 2 is a diagram illustrating a power spectrum and a peak ratio obtained by a moving average in the present invention.

FIG. 3 is an explanatory diagram for obtaining a moving average in the present invention.

FIG. 4 is a diagram illustrating a peak shape obtained by a moving average in the present invention.

FIG. 5 is a diagram illustrating an air spinning machine in the present invention.

FIG. 6 is a diagram showing details of the yarn unevenness detection device of FIG.

FIG. 7 is a diagram showing a power spectrum of a yarn unevenness signal.

FIG. 8 is a diagram showing a power spectrum of a yarn unevenness signal.

FIG. 9 is a diagram similarly showing a power spectrum of a yarn unevenness signal.

[Explanation of symbols]

 7 yarn unevenness detection device 22 Fourier transformer 24 moving average value calculation means 26 peak ratio determination means

Claims (4)

[Claims] 1. The yarn unevenness signal is spectrally analyzed, the analyzed spectral intensities are averaged over an arbitrary wavelength bandwidth, and the yarn is evaluated based on the average value data and the analyzed spectral data. Thread evaluation method. 2. The yarn evaluation according to claim 1, wherein a peak ratio is obtained from a peak detected from the power spectrum data and an average value of the peaks, and when the peak ratio exceeds an allowable value, it is judged that irregularity in cycle occurs. Method. 3. The yarn according to claim 1, wherein the average value is obtained by excluding an arbitrary number of spectral intensity values close to the maximum value and the minimum value among the spectral intensity values in the wavelength band for which the average value is obtained. Evaluation methods. 4. A yarn unevenness detection device for detecting a yarn unevenness signal of a spun yarn, a Fourier transformer for spectrum analysis of the yarn unevenness signal from the yarn unevenness detection device, and an average value from a calculation signal from the Fourier transformer. A mean value calculating means, a peak ratio judging means for judging a peak ratio from the mean value from the mean value calculating means and a spectrum intensity value from the Fourier transformer, and a time cycle irregularity when the peak ratio exceeds an allowable value. A yarn evaluation device, comprising: a cycle unevenness occurrence determining means for determining that the yarn is occurring.