JPH02307942A - Detector for defective shed of warp yarn group - Google Patents

Abstract

PURPOSE:To maintain discrimination accuracy regardless of a change in yarn quality, weaving width, machine model, etc., and detect an always sure defective shed by discriminating a defective shed based on a pulse signal prepared by changing a modulation signal of inspection light emitted to a warp yarn group opened with a prescribed period into binaries. CONSTITUTION:Inspection light is emitted from a light emitting diode to a warp yarn group opened with a prescribed period and the above-mentioned inspection light modulated by opening is then subjected to photoelectric conversion with a light receiving diode and outputted as a modulation signal. The aforementioned modulation signal is further passed through a low-pass filter to extract a pseudo-DC component. The signal is then subjected to level shift by a prescribed extent with a level shifting circuit, converted into a threshold voltage, further changed into binaries with a comparator, converted into a pulse signal and subsequently inputted to a discriminating logical circuit, which detects a defective shed, such as entangling accident of the above-mentioned warp yarn group, based on time axis information contained in the aforementioned pulse signal.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a shedding defect detection device for warp groups in a loom.

[Prior Art] In order to detect shedding defects in warp yarn groups caused by warp cutting, etc., various shedding defect detection devices have been provided. There is a device disclosed in Japanese Patent Nos. 63-1/15452.

This warp group defect detection device emits inspection light to the warp Y of the loom that opens and closes at a predetermined period, photoelectrically converts the inspection light modulated by the opening operation of the warp group, and obtains a modulated signal. The circuit is configured to binarize the obtained modulation signal using a predetermined threshold level as a reference, and detect a shedding defect in a warp group from a variation in the duty ratio of the obtained pulse signal.

This warp group shedding defect detection device converts the warp group shedding slam change, which changes due to the warp group shedding defect, into a change in the duty ratio of the pulse signal, so it can accurately detect the degree of shedding. , normal shedding (see Figure 5) and defective shedding with the smallest shedding angle due to warp entanglement, etc. (see Figure 5).
In addition to reliably distinguishing between incomplete openings caused by various causes (see Figure 6) and defective openings (see Figure 7),
It is also possible to determine.

[Problems to be Solved by the Invention] In general weaving, the color and thickness of the warp threads may be changed frequently, and naturally the modulation signal waveform obtained from the opening button of the warp group changes every time the warp threads are changed. It changes one by one.

However, in the warp group shedding defect detection device described above, the threshold level for binarization is set to a predetermined value, such as an intermediate value between the slice level on the high level side and the slice level on the low level side. Therefore, depending on the fluctuation of the modulation signal waveform, the difference in duty ratio of the pulse signal between normal opening and opening failure may decrease, and in extreme cases, it may not be possible to determine whether opening failure has occurred. was there. Furthermore, by changing the width of the woven fabric or changing the applied loom, the difference in duty ratio between normal shedding and poor shedding may be reduced for the same reason.

In addition, the threshold level for binarization is adjusted to the optimum level each time the warp is changed, and the threshold level is adjusted to the level with the largest change in duty ratio, and the threshold level is adjusted each time the woven fabric width or loom type is changed. The above problem can be overcome by adjusting. However, such solutions were cumbersome and impractical.

The present invention has been devised in view of the above-mentioned circumstances, and provides a warp group shedding defect detection device that can obtain high detection accuracy without adjustment despite changes in yarn quality, yarn weave V5 width, etc. is an issue that must be solved.

[Means for Solving the Problems] A warp group shedding defect detection device according to the present invention includes a light transmitting device that emits inspection light to a warp group of a loom that is sheared at a predetermined period, and a light beam that is modulated by the shedding of the warp group. a light receiving device that photoelectrically converts the inspection light and outputs a modulated signal; a binarization means that binarizes the modulated signal and converts it into a pulse signal; In the shedding defect detection device for a warp group, the binarization means extracts a pseudo DC level from the modulation signal, and extracts a predetermined amount from the extracted pseudo DC level. The present invention is characterized in that it consists of a threshold circuit that outputs a threshold level whose level has been shifted by a certain amount, and a comparison circuit that binarizes the modulated signal using the threshold level.

The light transmitting device may have a light emitting element such as a light emitting diode, a laser diode, etc., and the light emitting element may be operated continuously or may be modulated at a predetermined frequency. The light receiving device can have a photoelectric conversion element such as a photodiode or a phototransistor.

The modulation signal output from the light receiving device is modulated by the shedding operation of the warp thread group, which has a constant cycle, and is modulated at a constant cycle regardless of whether the shedding is normal or shedding is defective. The opening angle when the opening is defective is a narrower angle than when the opening is normal. In addition, the incomplete interrogation shown in Fig. 6 may be regarded as the same state as a defective opening (see Fig. 7), or the same state as normal 1; old] (see Fig. 5). Alternatively, this incomplete opening may be determined independently from normal opening and poor opening.

In addition, the amount of light received during normal aperture is compared to the amount of light received when the aperture is defective (m).
changes depending on the position of the inspection light in the aperture and whether transmitted light or repulsed light is received, but since the change characteristics of the amount of received light due to changes in these conditions are easy to understand, the following explanation will focus on the inspection light The case where the light transmits through the central region of the aperture will be explained as a typical example. In this case, the amount of received light decreases when the aperture is normal and when the aperture is defective.

As the time axis information of the pulse signal, either the pulse width or the pulse interval may be used, or both may be used. Furthermore, since the pulse period is determined by the rotational speed of the loom and is substantially constant in practice, the duty ratio may be used as the pulse width or in place of it.

The pseudo-DC level of the modulation signal includes a DC component and a very low-frequency AC component, and includes long-term fluctuation components based on the external environment, circuit characteristics, fiber quality, and the like.

The level shift (■) from the pseudo DC level is set as appropriate, but may be O depending on the case.

[Operation] The shedding slam of the warp group changes due to normal shedding and shedding failure of the warp group, and this change in the shedding slam changes the modulation signal waveform. The binarization means creates a pulse signal modulated according to the change in the modulation signal waveform, and the aperture defect determining means discriminates between a normal aperture and an aperture defect based on time axis information included in this pulse signal.

The threshold circuit of the binarization means extracts a pseudo DC level of the modulation signal, and a pseudo DC value level shifted by a predetermined level from this pseudo DC level is synthesized. The synthesized pseudo DC level is input to the binarization means to convert the modulation signal into two.
The modulated signal is converted into a pulse signal.

Therefore, when the yarn quality or fabric width changes, the threshold level, which is level-shifted by a predetermined period from the pseudo-DC level, follows the level fluctuation of the modulation signal, so it is always normal with stable accuracy. ” This makes it possible to determine whether the product is defective or not.

[Example] (Example 1) An example of the shedding defect detection device for a warp group of the present invention is shown in FIG.

This warp group shedding defect detection device includes a light transmitting device 1 that emits inspection light to the warp group F of the loom, which is sheared at a predetermined period, and a shedding of the warp group F (see Figs. 5 to 7). A light receiving device 2 that photoelectrically converts the inspection light obtained by the test and outputs a modulated signal 3n, and a preprocessing circuit 3 that preprocesses the modulated signal Sn.
, a binarization means 4 that binarizes the preprocessed modulation signal 3n and converts it into a pulse signal Sp, and a microcomputer (aperture defect determination means) that discriminates an aperture defect based on time information included in the pulse signal Sp. 5 and 11 controlled by microcomputer 5
It consists of an indicator 6.

The light transmitting device 1 includes a light emitting diode (not shown) and a beam diameter of 10-
25φ, and an AC power source (not shown) that supplies the light emitting diode with light emission power modulated at a carrier frequency of about 10kHz. It consists of a light receiving diode with a focusing lens that is supplied with a constant power supply voltage through a resistor (not shown).The light transmitting device 1 and the light receiving device 2 are connected to the loom (not shown) so as to face each other across the warp group F. ), and the inspection light output from the light transmitting device 1 passes through the central region near the base of the fan-shaped opening cross section of the warp group F (see Figs.
The light is received by the light receiving device 2 through four passes. The modulated signal 5ri (see FIG. 2) outputted from the output end of the light receiving device 2 is pre-processed by the pre-processing circuit 3 and sent to the binarization means 4.

That is, after the modulated signal 3n is amplified (or tuned amplified) by the amplifier circuit 3a, the carrier frequency and a frequency region in the vicinity thereof are extracted by the bandpass filter 3b. As a result, noise other than the above-mentioned necessary band components is removed. An excessively high level voltage value and an insufficiently low level voltage value which are synthesized by superimposing ripple components, noise components, etc. on the necessary band components are cut by the limiter 3C. The limiter 3C is composed of, for example, an anti-parallel diode connected between a signal line and a ground line. The necessary band components from which superimposed noise has been removed by the limiter 3C are detected by the detection circuit 3d, unnecessary high-frequency components are cut by the low-pass filter 3e, and only the low-frequency components are extracted as the modulated signal 3m. In addition, in this example, the bandpass filter is 8K)-IZ~
It has a passband of about 12KH2. The cutoff frequency of the low-pass filter 3e is set to about 1Kl-IZ.

The binarization means 4 includes a threshold circuit 4a consisting of a low-pass filter 41 having a pass band of several +Hz and degrees and a level shift circuit 42, and an inverter 4b. In other words,
Pseudo-DC component (more precisely, for example, several -
1-l-1z or less) is the low-pass filter 4.
1. This pseudo-DC component includes an extremely low frequency component that inevitably occurs due to changes in yarn quality or fabric width. J3, if the cutoff frequency of the low-pass filter 41 is set higher than the commercial frequency, the flicker component of the lighting equipment can be filtered out by the comparator 4.
Since it can be removed with b, it is right-handed. The pseudo DC component output from the low-pass filter 41 is level-shifted by a predetermined amount by a level shift circuit 42 and converted into a threshold voltage vth. As the level shift circuit 42, a well-known circuit configuration using a constant voltage diode or a high voltage diode can be adopted.

Note that here, the threshold voltage vth is approximately equal to the modulation signal S.
Each circuit constant is set to be an intermediate value of n. This circuit room! ! According to the standard, the incomplete opening shown in FIG. 6 is classified as the normal opening side. The comparator 4b has a modulation signal Sm
is binarized, converted into a pulse signal Sp, and inputted to the discrimination logic circuit 5.

The discrimination logic circuit 5 is constituted by a microcomputer, and determines the pulse width τ and pulse period of the input pulse signal Sp, and then determines the duty ratio τ/T. That is, the discriminating logic circuit 5 detects the adjacent rising edge Eu shown in FIG.
, 1. -u to find the pulse period -', then count the time between the rising edge Fu and the following falling edge Ed to find the pulse width τ, and then the duty ratio τ/ Then, if the duty ratio τ/T is smaller than a preset reference threshold value, the indicator 6 is turned on as a shedding failure, and at the same time, the loom drive motor is stopped.

Note that the microcomputer configuring the discrimination logic circuit 5 [1]
- Since the chart is basically the same as that of the second embodiment described below, illustration and description thereof will be omitted.

In this embodiment, the modulation signal 3m shows a waveform Sm1 (see FIG. 2) corresponding to the opening and closing of the warp group in the normal shedding 15, but when a warp group shedding failure occurs, the waveform Sm2 (see FIG. (See Figure 2).

Furthermore, in the above embodiment, the incomplete aperture shown in FIG. By providing a threshold voltage vth, it is also possible to distinguish between normal opening, incomplete opening, and defective opening.

(Example 2) Another example of the shedding defect detection device for a warp group of the present invention is shown in the third example.
As shown in the figure.

This warp group shedding defect detection device includes a light transmitting device 1, a light receiving device 2, a low pass filter 3d for extracting a low frequency component of a modulated signal Sm output from the light receiving device 2, and a low frequency component extracted from the light receiving device 2. An A/D converts the signal into a digital signal and outputs a modulated signal @sn.
It consists of a converter 7, a microcomputer (opening defect determining means) 8 which converts the modulated signal 5r) to determine opening defects, and an indicator controlled by the microcomputer 8.

The operation of the microcomputer 8 will be explained using the flowchart shown in FIG.

First, the initial setting is performed (5100), and the modulation signal Sn- is read (S102>. Thereafter, the interrupt routine 5100 is periodically set.
00 and periodically reads the modulated signal 3n-.

Next, it is checked whether the modulation signal Sn- is larger than the threshold value ThJ (S104), and if Sn''>Th, the process proceeds to 3106 and the microcomputer's built-in counters A and B are started ( S106).The threshold value Th is the average value M
+level shift value ΔX, and average +1ffM is the average value (pseudo DC component in Example 1) of the modulation signal Sm input in the period 1 second before the current time.However, at the beginning of operation, the The average value Mx immediately before the operation of The predetermined average value MC is the average fio, M
used as

Further, the level shift 1 to (direction ΔX is a predetermined value stored in advance in the microcomputer 8, the counter B is a counter that measures the pulse period, and the counter Δ is a counter that measures the pulse width.

Next, it is checked whether the modulation signal 3n- is below the threshold value Th (31, 08), and if it is below, the counter A is stopped (3110).

Next, it is checked whether the modulation im signal SN- is larger than the threshold Th again (S112>, and if it is larger, the counter B
step 1 to step 5114) and measure the duty ratio A/B (S116).

Next, it is checked whether the duty ratio A/B is greater than or equal to a predetermined value R that is set in advance in the microcomputer 8 (3118), and if the duty ratio A/B is smaller than the predetermined value R, an alarm signal is issued as an indicator that the opening is insufficient. Output to 6 (8126
). Further, if the duty ratio Δ/B is equal to or greater than a predetermined value R, it is assumed that the opening is normal, and a new average value M is calculated 512
0>, a new threshold value Th-average value M+level shift value ΔX is determined (3122), and a light emission output control signal is output to the light emitting device 1. Note that this light emission output control signal is
The modulation signal Sn- inputted during one hour is averaged and the reciprocal thereof is obtained, and the light emitting device 1 emits light in proportion to this reciprocal. However, the first time after starting the loom operation,
The light emitting device 1 shall emit light in proportion to the reciprocal number determined for the last hour of the previous operating period, and if the reciprocal number deviates from a predetermined range, the light emitting device 1 will emit light at a preset value. It is output to the light emitting device 1 as an output control signal SL.

Thereafter, the process returns to Sl 06 and the routine is executed again.

The detection device of each embodiment described above has a simple circuit configuration, installation setting, and adjustment, and is independent of the rotational speed of the i-machine. Furthermore, since it utilizes the photoelectric effect, it can be installed in any type of loom, such as water looms, air looms, rapier looms, through looms, and vertical looms, without causing weaving scratches.

According to experiments and implementation tests, jacquard weaving shows that s
In a room with a rotation speed of less than 70 rpm, an air jet loom with an FLI machine with a rotation speed of 70 rpm or more, and even in a water jet room where water is sprayed onto the light-receiving element and light-emitting element, ultra-fine threads of 5 denier, etc. 2~
Even when using a thick thread such as a 3φ blanket, optical cutting could be detected reliably.

It is also unaffected by static electricity, electrical spike noise, atmospheric humidity changes, dust, fluffy water droplets, etc., and can detect the movement of the warp threads.

[Effects of the Invention] As described above, in the shedding defect detection device for a warp group according to the present invention, the binarization means converts the modulated signal into two using a threshold level shifted by a predetermined value from the pseudo DC component of the modulated signal. Because it is converted into a value, it prevents the discrimination accuracy from deteriorating even when changing the yarn quality, weaving width, weaving machine model, etc., and always reliably detects the difference between warp groups even without adjustment. Defects can be detected.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing a first embodiment of the present invention, Fig. 2 is a signal waveform diagram of each part thereof, Fig. 3 is a block diagram showing a second embodiment of the invention, and Fig. 4 is a block diagram showing a second embodiment of the invention. The flowchart of the example, Fig. 5 is a schematic diagram showing normal shedding of the warp group of the loom, Fig. 6 is a schematic diagram showing incomplete shedding of warp 11\, and Fig. 7 is a schematic diagram showing defective shedding of the warp group. be. 1... Light transmitting device 2... Light receiving device 4...2
Shipping means 4a... Threshold value circuit 4b... Comparison circuit 5... Opening defect determination means Fig. 2 Eu

Claims (1)

[Claims] (1) a light transmitting device that emits inspection light to a warp group of a loom that is opened at a predetermined period; a light receiving device that photoelectrically converts the inspection light modulated by the shedding of the warp group and outputs a modulated signal; A shedding defect in a warp group, comprising a binarization means for binarizing a modulation signal and converting it into a pulse signal, and a shedding defect determination means for detecting an entanglement accident in a warp group based on time axis information included in the pulse signal. In the detection device, the binarization means extracts a pseudo DC level from the modulation signal, and includes a threshold circuit that outputs a threshold level that is level-shifted by a predetermined amount from the extracted pseudo DC level;
A shedding defect detection device for a warp group, comprising a comparison circuit that binarizes the modulation signal based on the threshold level.