JPWO2010026881A1 - Discrimination device and discriminating method for occurrence of transverse muscle - Google Patents

Abstract

The yarn friction data is measured, and the strength of the long-period component when the measured friction data is decomposed into the periodic components of friction fluctuations is obtained. It is determined that the strength is equal to or greater than a predetermined condition, and the yarn causes a transverse streak when the knitted fabric is knitted with a knitting machine. It can be determined whether or not the yarn has a transverse line when the knitted fabric is knitted.

Description

  The present invention relates to discriminating whether or not a yarn has a transverse stripe when knitted by a knitting machine.

  The knitted fabric may have horizontal stripes, which may significantly reduce the commercial value of the knitted fabric. However, on the other hand, depending on the yarn, the horizontal stripes may be the texture of the knitted fabric. Whether or not a horizontal streak is generated depends on the yarn used. Generally, a knitting machine with a coarse gauge (number of needles per inch) hardly generates a horizontal streak. It is said that it becomes easy to do. Further, in the case of wool, it is considered that the horizontal streak is not conspicuous with the spun yarn having a non-uniform shape of the yarn itself, and the streak is conspicuous with the worsted yarn having the uniform shape of the yarn. An example of the horizontal streak of the knitted fabric knitted by the flat knitting machine is shown in FIG. Note that X is the direction in which the carriage travels during knitting in the wale direction, and Y is the course direction and the vertical direction of the knitted fabric. From FIG. 18, it can be seen that the change in the state of the yarn over a long period is related to the transverse stripe.

  It is necessary to determine whether the thread is prone to cause horizontal stripes. It is known to measure yarn unevenness for quality control in spinning. For example, Patent Document 1: JP3520159B discloses that a yarn weight distribution is measured and Fourier-transformed and output as a spectrogram. Patent Document 2: JPH03-229106A discloses that the yarn unevenness is obtained by optically measuring the yarn diameter and the like. The spectrogram when the weight distribution of the yarn is measured and Fourier transformed is shown in FIGS. FIG. 14 corresponds to a thread (No. 1 in Table 1) where no horizontal stripe occurs, and FIGS. 15, 16, and 17 correspond to a thread (No. 5, 7, 8 in Table 1) where a horizontal stripe occurs. It is only in FIG. 16 corresponding to the No. 7 yarn that there is mass unevenness, and it cannot be discriminated whether or not horizontal stripes are generated on the spectrogram of the weight distribution.

  Table 1 shows the degree of unevenness of the yarn measured optically and the coefficient of variation CV of the friction data for 11 types of yarn. When the knitted fabric was knitted with a flat knitting machine using the 5th to 10th yarns, wefts were generated. The data in the right column of Table 1 is obtained by picking up the number of portions that are 50% or more thinner and thicker than the average for a 100 m yarn. Yarns of No. 8 to No. 10 were spun with remarkable yarn unevenness, and horizontal streaks were generated in all. However, it is natural that the horizontal streaks are generated with extremely uneven yarns. Actually, it is necessary to distinguish and distinguish yarns with horizontal streaks like Nos. 5 to 7 from yarns with uneven yarn thickness but no horizontal streaks like Nos. 1 and 3. Discrimination is difficult.

  The column of CV in Table 1 shows the coefficient of variation of the friction data, that is, the value obtained by dividing the standard deviation of the friction data by the average value. It can be seen that if the CV is large, the horizontal stripes are likely to occur, but it is difficult to explain that the horizontal stripes do not occur with the 4th yarn and the horizontal stripes occur with the 5th and 6th yarns. Therefore, it is necessary to find a parameter that can predict whether or not a horizontal stripe occurs.

JP3520159B JPH03-229106A

It is an object of the present invention to make it possible to determine whether or not the yarn has a transverse line when the knitted fabric is knitted.
An auxiliary problem of the present invention is to make it possible to accurately measure the signal on the long period side when the friction data of the yarn is Fourier transformed.

According to the present invention, there is provided an apparatus for discriminating the occurrence of lateral stripes, a measurement unit for the friction data of a yarn, a calculation means for data representing a coefficient of variation comprising a ratio between a standard deviation and an average value of the friction data, and the friction data as a cycle of friction fluctuation. A conversion unit for breaking down into components;
When the coefficient of variation is greater than or equal to a first predetermined value, the coefficient of variation is less than the first predetermined value and greater than or equal to a second predetermined value, and the friction data is further decomposed into periodic components by the conversion unit, Discriminating means for discriminating that a yarn having a long-period component strength of a predetermined condition or more is a yarn in which a transverse streak is generated when a knitted fabric is knitted by a knitting machine.

Further, in the method for determining the occurrence of lateral stripes of the present invention, the friction data of the yarn is measured, data representing a coefficient of variation consisting of the ratio between the standard deviation and the average value of the measured friction data is calculated, and the friction data is converted into the cycle of the friction variation. Breaks down into ingredients,
The length when the variation coefficient is less than the first predetermined value and the variation coefficient is less than the first predetermined value and greater than or equal to the second predetermined value, and the friction data is further decomposed into periodic components by the conversion unit It is determined that a yarn having a periodic component strength equal to or greater than a predetermined condition is a yarn in which a transverse stripe is generated when a knitted fabric is knitted by a knitting machine.

In this specification, the description relating to the discriminating apparatus also applies to the discriminating method as it is, and conversely, the description relating to the discriminating method also applies to the discriminating apparatus as it is.
The determination is not to reliably predict, but to determine whether the probability of occurrence of a horizontal stripe is high or low.
The first predetermined value of the coefficient of variation is selected from the range of 2.8 to 3.2%, for example, and more narrowly 2.9 to 3.1%. In the embodiment, the first predetermined value is 3%, and the second predetermined value is, for example, 1 It is selected from the range of 0.8% to 2.2%, more narrowly 1.95% to 2.1%, and 2% in the embodiment. But rather than these values themselves,
・ It is possible to roughly determine whether or not horizontal stripes occur depending on the variation coefficient,
-Although it is difficult to discriminate between the first predetermined value and the second predetermined value from the coefficient of variation, it is important that it can be discriminated based on the strength of the long-period component. Therefore, it is not necessary to limit the value of the specific variation coefficient as the predetermined value, and the values of the first and second predetermined values may be determined appropriately. The variation coefficient is the ratio between the standard deviation and the average value, and it is not necessary to literally obtain the variation coefficient. For example, the square of the standard deviation, that is, the ratio between the variance and the square of the average value may be used. . That is, it is important to discriminate from the variation coefficient, and it is arbitrary whether the variation coefficient is obtained directly or the variation coefficient is obtained indirectly from other values.

In Table 1, the horizontal streaks occur in the 5th to 10th yarns. It is determined that the No. 7 to No. 10 yarns have a variation coefficient CV equal to or greater than a first predetermined value, for example, 3% or more, and a horizontal line is generated without using the strength of the long period component in the FFT value. it can. In fact, in Table 1, when CV is 3% or more, the FFT value is also large, and horizontal stripes occur in all samples. CV is a dimensionless quantity given by the following equation.
CV = [Xavg] ⁻¹ · {∫L ⁻¹ [X−Xavg] ² dl} ^1/2 : X is friction data,
Xavg is the average value of the friction data at the measurement length L, the integral variable is the length or time, or if the CV is less than 2%, the FFT value is small and no horizontal streak occurs in all samples. However, it can be predicted that no transverse stripes will occur. In other words, the FFT value is indispensable when the CV is 2% or more and less than 3% (second predetermined value or more and less than the first predetermined value), in other words, a range that cannot be determined only by the CV.

  When the CV is greater than or equal to a second predetermined value and less than the first predetermined value, the inventor may generate lateral stripes due to the strength of a long-period component of frictional fluctuation, for example, a wavelength of 50 cm to 10 m, particularly a wavelength of 50 cm to 5 m. It was found that it could be distinguished. FIG. 10 shows the FFT data of the yarn in which the horizontal stripe does not occur, and FIGS. 11 and 13 show the FFT data of the yarn in which the horizontal stripe occurs. In FIG. 10, there is a peak at a wavelength of 1.16 m, but the FFT value of the peak is about 110 and is weak. In FIG. 11, there is a peak at a wavelength of 1.6 m, and the FFT value is strong at about 254. In FIG. 13, there are peaks at wavelengths of 1.22 m, 2.55 m, and 5.12 m, and the FFT value of the peak at 5.12 m is as strong as about 491. The peaks at wavelengths of 1.22 m and 2.55 m are the fourth and second harmonics of the 5.12 m peak. Therefore, if it is determined whether or not there is a strong peak on the long cycle side, the occurrence of transverse stripes can be predicted. If it can be predicted whether or not the horizontal streak will occur, it is possible to reduce the knitting of useless knitted fabric.

  The inventor has found that when the long-period component of the friction data of the yarn is measured, the result differs depending on the interval between units in the measuring device. FIG. 2 shows a friction measuring unit known per se, in which friction is applied to the thread 23 by the friction body 20, the tension is measured by the front and rear tension measuring units 21 and 22, and the frictional force is obtained from the difference in tension. Further, the yarn 23 is wound up by the winding roller 24, and the tension is applied to the yarn 23 by the tension applying unit 30. Here, when the interval between the members 20 to 22 and the roller 24 or the interval between the members 20 to 22 and the tension applying unit 30 is changed, the peak position on the long cycle side of the FFT value may change. Further, even if the winding speed of the roller 24 is changed, the peak position of the long period component of the FFT value may change. However, there is a peak of the FFT value on the long cycle side that does not change its position even if the interval between members is changed or the winding speed (yarn feed speed) is changed. A peak that appears, disappears, or moves depending on the speed or the interval between members can be estimated as noise. The FFT value is friction data, for example, a Fourier transform value of the tension difference between the inlet side and the outlet side. The FFT value depends on the tension and the like, and the applied tension is preferably changed depending on the thickness of the yarn. Therefore, the FFT value itself is not meaningful, but the relative magnitude of the FFT value is meaningful.

  Therefore, the yarn friction data measurement unit measures the yarn friction data at a plurality of yarn feed speeds using a yarn winding roller having a variable rotation speed, and determines the feed speed among the long period components. Even if it is changed, the strength of the long period component is obtained from the common peak and used to determine whether or not the thread has a transverse streak.If the peak generated, disappeared or moved by changing the feed rate is discarded as noise, The true peak on the period side can be obtained.

Block diagram of the discrimination device of the embodiment Block diagram of friction measuring instrument in the embodiment The figure which shows the FFT value when the yarn is fed at the yarn feeding speed of 25 cm / sec The figure which shows the FFT value when sending the yarn at the yarn feed speed of 50cm / sec The figure which shows the FFT value when the yarn is fed at the yarn feeding speed of 75 cm / sec It is a figure which shows the friction data of the thread | yarn 1 of Table 1, A friction data is shown in the upper part of a figure, and the tension | tensile_strength data of the entrance side are shown in the lower part. It is a figure which shows the friction data of the thread | yarn 5 of Table 1, A friction data is shown in the upper part of a figure, and the tension | tensile_strength data of the entrance side are shown in the lower part. It is a figure which shows the friction data of the thread | yarn 7 of Table 1, A friction data is shown in the upper part of a figure, and the tension | tensile_strength data of the entrance side are shown in the lower part. It is a figure which shows the friction data of the thread | yarn 8 of Table 1, A friction data is shown in the upper part of a figure, and the tension | tensile_strength data of the entrance side are shown in the lower part. The figure which shows the FFT value of the friction data of the thread | yarn 1 of Table 1 The figure which shows the FFT value of the friction data of the thread | yarn 5 of Table 1 The figure which shows the FFT value of the friction data of the thread | yarn 7 of Table 1 The figure which shows the FFT value of the friction data of the thread | yarn 8 of Table 1 A diagram showing a spectrogram with respect to the weight fluctuation of the yarn 1 in Table 1 (conventional example) The figure which shows the spectrogram with respect to the weight fluctuation | variation of the thread | yarn 5 of Table 1 (conventional example) The figure which shows the spectrogram with respect to the weight fluctuation of the thread | yarn 7 of Table 1 (conventional example) The figure which shows the spectrogram with respect to the weight fluctuation of the thread | yarn 8 of Table 1 (conventional example) Photograph of knitted fabric with horizontal stripes in the conventional example

  In the following, an optimum embodiment for carrying out the present invention will be shown.

  1 to 13 show an embodiment. FIG. 1 shows a discriminating device 2 for generating horizontal stripes. Reference numeral 4 denotes a friction measurement unit which outputs yarn friction data. A memory 6 stores the output of the friction measurement unit 4. The statistical processing unit 8, FFT 10 and wavelet transform. To the unit 12. The statistical processing unit 8 may output a coefficient of variation CV for the friction data of the yarn, and may output other statistical data such as an average value of friction, a standard deviation, a kurtosis degree, and a distortion degree. The fast Fourier transform unit (FFT) 10 may perform fast Fourier transform on the friction data, particularly output a long period component thereof, and transform to an orthogonal function system other than a trigonometric function. The wavelet transform unit 12 is a substitute for the FFT 10 and may not be provided. The output unit 14 determines, based on the output of the statistical processing unit 8, for example, the output of the CV and the FFT 10, whether a horizontal streak is generated when the knitted fabric is knitted using the yarn. Hereinafter, the Fourier transform value (FFT value) is the square root of the sum of the square of the real component of the Fourier transform and the square of the imaginary component. Further, the Fourier transform is not limited to the literal Fourier transform, but includes a simplified Fourier transform such as a discrete cosine transform.

  FIG. 2 shows the configuration of the friction measurement unit 4, which is known per se. Reference numeral 20 denotes a friction body, which is composed of a pin, a cylinder, or the like, and applies friction to the yarn 23. A take-up roller 24 is driven by a motor 26, and the number of rotations is variable. Reference numerals 27 to 29 denote guide rollers, and the tension measuring units 21 and 22 measure the tensions T1 and T2 of the yarn 23 in the vicinity of the guide rollers 27 and 28. A tension applying unit 30 includes a plurality of rollers, and changes the tension between the cone 32 and cheese (not shown) and the guide roller 28. The control unit 34 changes the number of rotations of the winding roller 24, that is, the feed speed of the yarn 23 in, for example, three stages, and outputs the difference between the tensions T1 and T2 measured by the tension measuring units 21 and 22 as friction data.

  When the friction data in the friction measuring unit 4 is Fourier transformed, the long period component is the feed speed of the yarn 23, the interval between the elements 20-22 and the tension applying unit 30, or the interval between the elements 20-22 and the take-up roller 24. May vary. These can be considered as a kind of natural vibration in the friction measuring unit 4 mixed in the friction data of the yarn 23. Therefore, in order to cut such noise, the winding speed of the winding roller 24 was changed to, for example, three types of 25 cm / second, 50 cm / second, and 75 cm / second, and the friction data was subjected to Fourier transform. Three types of Fourier transform values for the same yarn are shown in FIGS.

  3 to 5, the peak at a wavelength of 92 to 95 cm is common. In FIG. 3, two peaks in the wavelength range of 40 cm are not seen in FIG. 4, and the peak at a wavelength of 28 cm is not seen in FIG. Instead, FIG. 4 has peaks at a wavelength of 67 cm and a wavelength of 33 cm. 3 and 4, a peak with a wavelength of about 74 cm exists, but in FIG. 5, this peak disappears. Instead, a peak with a wavelength of 155 cm and a peak with a wavelength of about 21 cm appear, and a peak with a wavelength of about 47 cm is restored.

  As described above, when the yarn feed speed is changed, a peak generated, disappeared or moved is a kind of noise caused by a kind of natural vibration in the friction measuring unit 4. On the other hand, the peak due to the properties of the yarn 23 itself is at a wavelength of 92 to 95 cm in FIGS. 3 to 5 and the position does not change. Furthermore, even if the distance between the elements 20 to 22 and the tension applying unit 30 was changed or the distance between the take-up roller 24 was changed, the peak at the wavelength of 90 cm in FIGS. 3 to 5 did not move. Therefore, a peak that does not move even if the winding speed is changed is defined as a true peak. In the embodiment, the winding speed is changed to three types, but may be changed to two types.

  In order to evaluate whether or not a horizontal streak occurs when knitting with a flat knitting machine, ten types of yarns shown in Table 1 were used. Among these, the worsted yarn is a yarn in which transverse stripes are more likely to occur than the spun yarn. The yarn obtained by spinning No. 8 to No. 10 hemp is particularly a yarn in which the horizontal stripe is likely to occur, but the horizontal stripe may be a texture. Therefore, when the problem is simplified, it will be explained that the horizontal streak is generated with the 5th to 7th eyelashes even though the 3rd and 4th eyelashes do not generate the horizontal streak. In particular, in the coefficient of variation CV, the 4th eyelash yarn is larger than the 6th eyelash yarn, but there is no reason why the horizontal streak does not occur. A count such as 2/48 means a twin yarn of 48 m / g. The No. 11 yarn in Table 1 has no horizontal streak even though the FFT peak value (period: 106.7 cm) is large. This indicates that complete discrimination cannot be made only with the FFT value.

  6 to 9 show the friction data of No. 1 yarn in Table 1 and the friction data of No. 5, No. 7, and No. 8 yarns. 6 has a coefficient of variation of 1.52% and no horizontal streak, the number 5 thread of FIG. 7 has a coefficient of variation of 2.83% and has a horizontal line, and the number 7 yarn of FIG. A horizontal stripe occurs when the coefficient is 3.17%, and the variation coefficient is 4.13% as large as the eighth thread in FIG. In these drawings, the lower line is the tension measured by the tension measuring unit 22 on the inlet side.

  10 to 13 show the FFT values for the No. 1 yarn, No. 5 yarn, No. 7 yarn and No. 8 yarn in Table 1. 10 to 13 show the results when the yarn feed speed is 50 cm / sec, and the portions that are found to be noise are marked as compared with the measurement results of 25 cm / sec and 75 cm / sec. The measured yarn length is about 200 m. The strong peak marked in the figure is the peak on the long period side, and the numbers indicate the period (wavelength) in cm. The horizontal axis indicates the period, and the frequency obtained by FFT is converted to the period, so the component on the long period side is biased to the right side of the figure. The vertical axis is the FFT value and the peak height. In the No. 1 yarn of FIG. 10, there is no transverse streak and the peaks are at 116 cm and 320 cm, but these are discrete peaks that are not related to each other between the fundamental wave and the harmonics. The FFT value is about 110 at the maximum and is not large.

  FIG. 11 corresponds to the No. 5 yarn, which has a horizontal stripe, has a single strong peak at a wavelength of 160 cm, and has a high FFT value of about 254. FIG. 12 corresponds to the No. 7 yarn, a horizontal stripe occurs, has a peak at a wavelength of 119.1 cm, etc., and the peak value of FFT is slightly high at 157.6. FIG. 13 shows the result of No. 8 yarn in which the horizontal streak occurs. The three peaks at 122 cm, 255 cm, and 512 cm are in a relationship of the fourth harmonic, the second harmonic, and the fundamental wave, and the peak of the fundamental wave is extremely high at 491. .

  As shown in Table 1, the presence or absence of transverse stripes can be almost predicted by the CV value, and when CV is 3% or more, it can be reliably predicted that the transverse stripes are generated regardless of the FFT value. Moreover, when CV is less than 2%, it can be predicted that no horizontal streak occurs regardless of the FFT value. In CV, it is difficult to predict the presence or absence of lateral stripes in the case of 2 to 3%. In this case, the FFT value is particularly significant.

  In the FFT value, it is determined whether there is a strong peak having a large FFT value for a long-period component, particularly a component having a wavelength of 50 cm to 10 m, more specifically, a component having a wavelength of 50 cm to 5 m. As shown in Table 1, in the yarn in which the horizontal stripes are generated, the peak of the FFT value in the period of the wavelength of 50 cm to 5 m is 110 or less when the horizontal stripes are not generated, and 160 or more when the horizontal stripes are generated. If the peak FFT value for the yarn is determined to be 140 or less and less than 140, it is possible to determine the occurrence of a horizontal stripe.

  Although the peak height is used here as the FFT value, it may be the peak area above the baseline. Further, as shown in FIG. 13, when both the fundamental wave and the harmonic wave appear, the values of these peaks may be added without weighting or multiplied by an appropriate weighting factor.

  It can be estimated that the cause of the peak in the FFT value at a period of about 50 cm to 5 m is due to the twisting process in the process of spinning the yarn. That is, when the degree of twist of the yarn is periodically changed, the frictional characteristics of the yarn are periodically changed, which seems to be the cause of the data in Table 1. The degree of twist affects the friction between the yarn and the needle when knitting with the needle and the extent to which the yarn is stretched, and it can be estimated that the horizontal streak occurs when the degree of twist changes over a long period. Next, it is considered that the frictional characteristics of the yarn repeatedly fluctuate with a period of about 100 cm because the friction coefficient fluctuates due to the influence of traverse during yarn processing. It seems that it is getting bigger.

  In order to detect signals with low regularity in a predetermined period range, the wavelet transform may be more suitable than the fast Fourier transform. In the wavelet transform, friction data is converted into data on a two-dimensional plane of time and frequency. Thus, for example, if the wavelet transform unit 12 is provided so as to output data having a wavelength of about 50 cm to 5 m, the FFT 10 can be substituted.

  14 to 17 show the measurement results of the yarn unevenness tester for No. 1 yarn, No. 5 yarn, No. 7 yarn and No. 8 yarn in Table 1. The yarn unevenness tester measures the weight distribution of the yarn and outputs, for example, a portion that is 50% thinner or thicker than the average value as a yarn unevenness. In the yarn unevenness testing machine, it can be predicted that the horizontal streak will be generated with the 8th to 10th yarns, but these are yarns that fluctuate greatly. Not only that, the yarn unevenness tester can fast Fourier transform the yarn weight change and output the wavelength component as a spectrogram. 14 to 17 show such data, and the peak near the wavelength of 1 m shown in FIGS. 10 to 13 is not found. Further, it is difficult to explain that the horizontal streak does not occur in the yarn of FIG. 14, and the horizontal streak occurs in the yarn of FIGS.

In the embodiment, the following effects can be obtained.
(1) When a yarn is knitted using a flat knitting machine or a circular knitting machine, it can be determined whether or not a horizontal line is generated. Therefore, the knitting of useless knitted fabric is reduced.
(2) With the coefficient of variation CV, it is difficult to determine the presence or absence of lateral stripes, and it is possible to accurately determine the presence or absence of lateral stripes in an area where the CV is 2 to 3%.
(3) By changing the yarn feed speed when measuring friction data, noise generated in the FFT data on the long cycle side can be eliminated.

2 Discriminating device 4 Friction measuring unit 6 Memory 8 Statistical processing unit 10 Fast Fourier transform unit (FFT)
DESCRIPTION OF SYMBOLS 12 Wavelet conversion part 14 Output part 20 Friction body 21,22 Tension | tensile_strength measurement part 23 Yarn 24 Winding roller 26 Motor 27-29 Guide roller 30 Tension provision part 32 Cone 34 Control part

The apparatus for determining the occurrence of lateral stripes according to the present invention includes a yarn friction data measurement unit for measuring yarn friction data that changes with time while feeding the yarn, and a variation consisting of a ratio between a standard deviation and an average value of the friction data. A means for calculating data representing a coefficient, a conversion unit for decomposing friction data into periodic components of friction fluctuations,
When the coefficient of variation is greater than or equal to a first predetermined value, the coefficient of variation is less than the first predetermined value and greater than or equal to a second predetermined value, and the friction data is further decomposed into periodic components by the conversion unit, Discriminating means for discriminating that a yarn having a long-period component strength of a predetermined condition or more is a yarn in which a transverse streak is generated when a knitted fabric is knitted by a knitting machine.

In the method for determining the occurrence of lateral stripes according to the present invention, while the yarn is fed, the friction data of the yarn changing with time is measured , and the data representing the coefficient of variation consisting of the ratio between the standard deviation and the average value of the measured friction data is calculated. At the same time, the friction data is broken down into periodic components of friction fluctuations,
The length when the variation coefficient is less than the first predetermined value and the variation coefficient is less than the first predetermined value and greater than or equal to the second predetermined value, and the friction data is further decomposed into periodic components by the conversion unit It is determined that a yarn having a periodic component strength equal to or greater than a predetermined condition is a yarn in which a transverse stripe is generated when a knitted fabric is knitted by a knitting machine.

The inventor has found that when the long-period component of the friction data of the yarn is measured, the result differs depending on the interval between units in the measuring device. FIG. 2 shows a friction measuring unit known per se, where friction is applied to the thread 23 by the friction body 20, the tension is measured by the front and rear tension measuring units 21 and 22, and the frictional force is obtained from the difference in tension. Further, the yarn 23 is wound up by the winding roller 24, and the tension is applied to the yarn 23 by the tension applying unit 30. Here, when the interval between the members 20 to 22 and the roller 24 or the interval between the members 20 to 22 and the tension applying unit 30 is changed, the peak position on the long cycle side of the FFT value may change. Further, even if the winding speed of the roller 24 is changed, the peak position of the long period component of the FFT value may change. However, there is a peak of the FFT value on the long cycle side that does not change its position even if the interval between members is changed or the winding speed (yarn feed speed) is changed. A peak that appears, disappears, or moves depending on the speed or the interval between members can be estimated as noise. The FFT value is friction data, for example, a Fourier transform value of the tension difference between the inlet side and the outlet side. The FFT value depends on the tension and the like, and the applied tension is preferably changed depending on the thickness of the yarn. Therefore, the FFT value itself is not meaningful, but the relative magnitude of the FFT value is meaningful.

Block diagram of the discrimination device of the embodiment Block diagram of the friction measurement unit in the embodiment The figure which shows the FFT value when the yarn is fed at the yarn feeding speed of 25 cm / sec The figure which shows the FFT value when sending the yarn at the yarn feed speed of 50cm / sec The figure which shows the FFT value when the yarn is fed at the yarn feeding speed of 75 cm / sec It is a figure which shows the friction data of the thread | yarn 1 of Table 1, A friction data is shown in the upper part of a figure, and the tension | tensile_strength data of the entrance side are shown in the lower part. It is a figure which shows the friction data of the thread | yarn 5 of Table 1, A friction data is shown in the upper part of a figure, and the tension | tensile_strength data of the entrance side are shown in the lower part. It is a figure which shows the friction data of the thread | yarn 7 of Table 1, A friction data is shown in the upper part of a figure, and the tension | tensile_strength data of the entrance side are shown in the lower part. It is a figure which shows the friction data of the thread | yarn 8 of Table 1, A friction data is shown in the upper part of a figure, and the tension | tensile_strength data of the entrance side are shown in the lower part. The figure which shows the FFT value of the friction data of the thread | yarn 1 of Table 1 The figure which shows the FFT value of the friction data of the thread | yarn 5 of Table 1 The figure which shows the FFT value of the friction data of the thread | yarn 7 of Table 1 The figure which shows the FFT value of the friction data of the thread | yarn 8 of Table 1 A diagram showing a spectrogram with respect to the weight fluctuation of the yarn 1 in Table 1 (conventional example) The figure which shows the spectrogram with respect to the weight fluctuation | variation of the thread | yarn 5 of Table 1 (conventional example) The figure which shows the spectrogram with respect to the weight fluctuation of the thread | yarn 7 of Table 1 (conventional example) The figure which shows the spectrogram with respect to the weight fluctuation of the thread | yarn 8 of Table 1 (conventional example) Photograph of knitted fabric with horizontal stripes in the conventional example

Claims (4)

A measurement unit for the friction data of the yarn, a calculation means for data representing a coefficient of variation consisting of a ratio between the standard deviation and the average value of the friction data, a conversion unit for decomposing the friction data into periodic components of friction variation,
When the coefficient of variation is greater than or equal to a first predetermined value, the coefficient of variation is less than the first predetermined value and greater than or equal to a second predetermined value, and the friction data is further decomposed into periodic components by the conversion unit, A discriminating device for the occurrence of a lateral streak, comprising: discriminating means for discriminating that a yarn having a long-period component strength of a predetermined condition or more is a yarn in which a lateral streak is generated when a knitted fabric is knitted with a knitting machine. The yarn friction data measuring unit includes a yarn winding roller with a variable rotation speed, and measures yarn friction data at a plurality of yarn feed speeds.
The discriminating means obtains the strength of the long-period component from the common peak even if the feed rate is changed among the long-cycle components, and uses it to discriminate whether or not the yarn has a transverse stripe, thereby changing the feed rate. The horizontal streak generation discriminating apparatus according to claim 1, wherein peaks that are generated, disappeared, or moved by the step are discarded as noise. Measure the yarn friction data, calculate the data representing the coefficient of variation consisting of the ratio between the standard deviation and the average value of the measured friction data, and decompose the friction data into periodic components of the friction variation,
The length when the variation coefficient is less than the first predetermined value and the variation coefficient is less than the first predetermined value and greater than or equal to the second predetermined value, and the friction data is further decomposed into periodic components by the conversion unit A method for determining the occurrence of a transverse streak, wherein a yarn having a periodic component strength of a predetermined condition or more is judged to be a yarn that produces a transverse streak when the knitted fabric is knitted with a knitting machine. Using a yarn take-up roller with variable rotation speed, measure the friction data of the yarn at multiple yarn feed speeds,
Among the long-period components, even if the feed rate is changed, the strength of the long-cycle component is obtained from a common peak, and is used to determine whether or not the yarn has a transverse streak. Alternatively, the method for determining the occurrence of horizontal stripes according to claim 3, wherein the moving peak is discarded as noise.