JPH09228163A - Sliver unevenness collector in spinning machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably perform collection and control of unevenness of sliver in a straight spinning and a mixed spinning. SOLUTION: This sliver unevenness collector has an electrostatic capacity type cross section size detector A1 at an inlet side of plural pairs of draft rollers Rb and Rf constituting a draft zone D and similarly an air micrometer type cross section size detector A2 at a position as possible as near an outlet side. An opened loop control and a closed loop control are constituted by providing every comparing circuits C1 and C2 to which every signals B1 and B2 from the every detectors A1 and A2 and a speed controlling circuit C sending a command to a servo motor controlling every rotating speeds of the plural pairs of draft rollers Rb and Rf . When the second signal B2 from the outlet side detector A2 goes over a prescribed comparing value, the first signal B1 from the inlet side detector A1 is compared with the prescribed value, then a level discrimination-type closed loop control controlling every rotating speeds of the plural pairs of draft rollers Rb and Rf are performed according to the result.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a sliver spot correction device for a spinning machine.

[0002]

2. Description of the Related Art As a sliver unevenness correcting device in a spinning machine, an open loop control having a section thickness detector A ₁ of the sliver S on the inlet side of the draft zone D and a section thickness of the sliver S on the outlet side of the draft zone D are provided. The techniques of closed loop control with a height detector A ₂ and combined control that combines open loop control and closed loop control are known. Next, each of these techniques will be described.

First, the open loop control will be described.
As shown in FIG. 6, a cross-section thickness detector A ₁ of the sliver S is arranged on the inlet side of the draft zone D to which the sliver S is supplied. The draft zone D includes a pair of back draft rollers Rb arranged on the upstream side and a pair of front draft rollers Rb arranged on the downstream side.
f and a plurality of pairs of draft rollers (not shown) disposed between the rollers Rb and Rf. One of the plurality of pairs of draft rollers Rb, Rf is shifted from a servo motor (not shown) via a differential device (not shown). The rotation speed of one of the rollers Rb, Rf is controlled by a command value sent from a speed control circuit C'to a servo motor (not shown). When the sliver S is uneven, the sectional thickness of the sliver S changes. The change is detected by the detector A ₁ on the inlet side,
The first signal B ₁ is input to the electronic circuit C ₁ 'and amplified. The first signal B ₁ is amplified and becomes a signal B ₁ ', which is input to the speed control circuit C', and a plurality of pairs of draft rollers R
The rotation speeds of b and Rf are controlled. The unevenness of the sliver S is corrected while the sliver S passes through the draft zone D. The sliver spot correction device P ₁ that performs open-loop control has the above-mentioned configuration, and this control is a method that can correct spots of a small wavelength of the sliver S (short period spots). The arrow with reference numeral 1 in FIG. 6 indicates the direction in which the sliver S is spun.

Typical detector A ₁ in open loop control
Is a capacitance type detector A ₁ . The principle of the capacitance type detector A ₁ will be described with reference to FIG. 7.
When the pair of positive and negative electrodes 2 face each other, a capacitance is generated between them. The capacitance changes depending on the mass of the substance entering between the pair of electrodes 2 and the water content. Therefore, when the sliver S enters, the capacitance changes. By detecting this change, the cross-sectional thickness of the sliver S can be measured.

As the detector A ₁ in the open loop control, a press type detector A ₁ ′ called a “measuring roller” may be used in addition to the capacitance type detector A ₁ described above. is there. In this press type detector A ₁ ′, as shown in FIG. 8, the sliver S enters between the pair of press rollers 4 via the sliver concentrator 3. While the sliver S passes between the pair of press rollers 4, the sliver S is compressed while the rollers 4 rotate in opposite directions 5 and 6, respectively, and the cross-sectional thickness thereof is measured. In this method, since the pair of press rollers 4 mechanically compress the sliver S, the fibers of the sliver S are cut, and the sliver S after passing between the pair of press rollers 4 is not loosened and is solidified. There was a problem that it was drafted as it was. Further, it is necessary to replace the pair of press rollers 4 and parts around them depending on the stage of the cross-sectional thickness of the sliver S supplied. Furthermore, a pair of press rollers 4
It required a lot of man-hours because it was necessary to adjust the intervals of.

Next, the closed loop control will be described. As shown in FIG. 9, the cross-section thickness detector A ₂ of the sliver S is arranged on the exit side of the draft zone D. Similar to the open loop control, the draft zone D is composed of a plurality of pairs of draft rollers Rb, Rf, and one of the draft rollers Rb, Rf is connected to a differential device (not shown) from a servo motor (not shown). ) Is being shifted through. The rotation speed of one of the rollers Rb, Rf is controlled by a command value sent from a speed control circuit C'to a servo motor (not shown). When the sliver S is uneven, the sectional thickness of the sliver S changes. The change is detected by the detector A ₂ , and the second signal B ₂ is input to the electronic circuit C ₂ 'and amplified. The second signal B ₂ is amplified and becomes a signal B ₂ ′, which is input to the speed control circuit C ′, and the rotation speeds of the plurality of pairs of draft rollers Rb and Rf are controlled. However, the unevenness of the sliver S is corrected while the sliver S is passing through the draft zone D, so that the detector A ₂ on the exit side is corrected.
A certain amount of time (dead time t) is required until the spots are detected and the rotational speeds of the plurality of pairs of draft rollers Rb, Rf are changed. The sliver spot correction device P ₂ that performs closed loop control has the above-described configuration. Next, the dead time t in the closed loop control will be described.

FIG. 10 shows changes in cross-sectional thickness of the sliver S (supply sliver) on the inlet side and the sliver S (spinning sliver) on the outlet side of the draft zone D with respect to spinning time. When unevenness occurs on the inlet side of the draft zone D, the cross-sectional thickness changes as indicated by the straight line 7. In the closed loop control, since no change is detected on the inlet side of the draft zone D, even if the sliver S passes through the draft zone D, the spots are spun without being corrected. When the detector A ₂ on the exit side detects a spot, a signal B ₂ 'is sent to the speed control circuit C'.
Is sent and the rotation speeds of the draft rollers Rb and Rf of a plurality of pairs are controlled to correct the spots.
Will pass. Therefore, it takes time to correct the unevenness of the sliver S on the outlet side, and the cross-sectional thickness of the spun sliver S changes as shown by the curve 8. The broken line 9 in the graph on the outlet side shows the change in cross-sectional thickness of the sliver S on the inlet side. The closed-loop control is a control method that cannot correct the short wavelength spots (short period spots) of the sliver S, but can correct the relatively long wavelength spots (medium-long period spots).

[0008] Detector A ₂ in a closed-loop control is generally detector A ₂ of the air micrometer type have been used. The air micrometer type detector A ₂ has a configuration in which compressed air having a constant pressure is made to flow into an inflow nozzle and is discharged to the atmosphere from an outflow nozzle via a sliver S in an instruction pressure chamber. At this time, the minute change in the area of the outflow nozzle portion is expanded to the pressure change in the indicator pressure chamber, and the cross-sectional thickness of the sliver S is measured.

Joint control in which both the open loop control and the closed loop control described above are combined is known. Next, the joint control will be described. As shown in FIG. 11, cross-section thickness detectors A _{1 and} A ₂ are arranged on the inlet side and the outlet side of the draft zone D, respectively. As a representative example,
The detector A ₁ on the inlet side is a capacitance type detector A ₁ ,
The detector A ₂ on the outlet side is an air micrometer type detector A
₂ The first signal B ₁ output from the detector A ₁ on the inlet side is amplified by the electronic circuit C ₁ ′, becomes a signal B ₁ ′, and is input to the speed control circuit C ′. Similarly, the second signal B ₂ output from the detector A ₂ on the exit side is the electronic circuit C ₂ '
The signal is amplified into the signal B ₂ 'and inputted to the speed control circuit C'. ', The respective signals B ₁ is inputted' speed control circuit C, the draft roller Rb pairs constituting the draft zone D in accordance with B ₂ ', to modify the respective rotational speed of the Rf. The sliver spot correction device P ₃ that performs the connection control has the above-described configuration. Coupling control is a control method that can correct sliver S from short wavelength spots (short period spots) to relatively long wavelength spots (medium to long period spots).

In the conventional coupled control, the short-period spots can be corrected by the open loop control, so that the closed loop control side does not require quick control. Therefore, the piping tube for supplying air to the air micrometer type detector A ₂ which is a typical closed loop control detector has a considerable margin,
That is, it was attached in a slack state. In addition, since a system with a small draft change width (brake draft system) is adopted, the distance from the air micrometer type detector A ₂ to a plurality of pairs of draft rollers Rb, Rf becomes long,
The dead time t was long.

Even in the case of the closed loop control, the method of drafting in the main draft zone is adopted, and the detector A ₂ on the outlet side is arranged as close as possible to the pair of front draft rollers Rf, and If the dead time t was shortened by making the piping tube for supplying air to A ₂ as short as possible without sagging, it was possible to correct unevenness of wavelength to some extent. However, it was not possible to correct a very short wavelength spot such as a break of the sliver S.

Further, in the above-mentioned coupling control, the unevenness of the sliver S can be corrected and controlled only for the sliver having the unified material (pure spinning), and for the sliver (mixed spinning) in which different materials are mixed. It was impossible for them. Next, the reason will be described. As described above, the capacitance type detector A ₁ measures the capacitance of the sliver S passing between the pair of electrodes 2 to measure the cross-sectional thickness thereof. If the material of the spun sliver S is the same, its capacitance can be measured stably. However, as shown in FIG. 12, if the material is a different sliver S and the sliver S 'are mixed (blended), the first signal B ₁ from the detector A ₁ of the electrostatic capacitance type not It became stable. Therefore, the whole control became unstable.

[0013]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has been made in view of stable control of correction of unevenness of blended spinning.

[0014]

In order to solve this problem, the means adopted by the present invention is a detector for measuring the sectional thickness of a sliver supplied to a draft zone and outputting a first signal, A means for controlling the rotational speeds of a plurality of pairs of draft rollers in the draft zone, and a detector for measuring the cross-sectional thickness of the sliver that has passed through the draft zone and outputting a second signal are provided. In the sliver spot correction device that performs at least one of open loop control and closed loop control by the rotation speed control means, the comparison values are previously input to the respective comparison circuits to which the first and second signals are input. A plurality of control constants are set in advance in the speed control circuit to which the command from each comparison circuit is input, and the second signal is set in the second comparison circuit in a predetermined ratio. When it exceeds the value, the first signal is first
Is compared with a preset comparison value in the comparison circuit of
Based on the result, level discriminant closed loop control for controlling each rotation speed of a plurality of pairs of draft rollers is performed, and a sliver spot correction device in a spinning machine is configured.

In the case of pure spinning, joint control is generally performed by combining open loop control using a capacitance type detector and closed loop control using an air micrometer type detector. In the case of the mixed spinning, the control mainly including the closed loop control is performed. When a spot that cannot be corrected only by the control mainly including the closed loop control occurs, the closed loop control accompanied by the level determination is performed.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below with reference to examples. Note that the same reference numerals are given to the same portions as those described in the item of the above-mentioned "Prior Art", and only the characteristic portions of the present invention will be described without duplicating description.

As shown in FIG. 1, the draft zone D
The cross-section thickness detector A of the sliver S supplied to the inlet side of the
₁ , and a cross-section thickness detector A _{2 of the} sliver S to be spun on the outlet side. Detector A on the inlet side
₁ is a capacitance type detector A _1, which is the detector A on the outlet side.
Reference numeral ₂ is an air micrometer type detector A ₂ . One of the plurality of pairs of draft rollers Rb, Rf is shifted from a servo motor (not shown) via a differential device (not shown). Drafting will be done in the main draft zone,
The detector A ₂ on the outlet side is mounted at a position as close as possible to the pair of front draft rollers Rf. In this case, since the main draft is used, the pair of front draft rollers Rf will not be shifted. Also, the slack of the piping tube for supplying air to the detector A ₂ on the outlet side is eliminated, and its length is made as short as possible. Detector A on the inlet side
First signal B ₁ output from the ₁ is input to the comparison circuit C _1. Here, the first signal B ₁ is compared with a preset comparison value. The result is input to the speed control circuit C as a command B ₃ . Similarly, the second signal B ₂ output from the detector A ₂ on the exit side is input to the comparison circuit C ₂ . Here, the second signal B ₂ is compared with a preset comparison value. The result is input to the speed control circuit C as a command B ₄ . The speed control circuit C, which operation is performed in response to the command B _3, B ₄ input, the draft roller Rb pairs except the pair of front draft roller Rf through a differential device (not shown) A command for controlling the rotation speed of a servo motor (not shown) for gear shift control is sent. The sliver spot correction device P according to the present invention has the above-described configuration.

The speed control circuit C has amplification factors Z ₁ and Z ₂ in open loop control and closed loop control, a closed loop control integration constant K ₁ and a closed loop control proportional constant K ₂ . Of these constants, the amplification factors Z ₁ and Z ₂ are preset by a test during the trial run of the spinning machine and are not changed during the operation of the spinning machine. Referring to FIGS. 2 to 5,
A method of calculating the amplification factors Z ₁ and Z ₂ will be described. The weight of the supplied sliver S is measured, and the supplied sliver S at the time of the first measurement
Of the feed sliver S during the second measurement is T
Let b. Each output of the capacitance type detector A ₁ is set to Va, Vb.
Then, the amplification factor Z ₁ in the open loop control is (Tb
-Ta) / (Vb-Va). Similarly, the weight of the spun sliver S to be spun is measured, and the weight of the spun sliver S at the first measurement is Tc, and the weight of the spun sliver S at the second measurement is Td. When the outputs of the air micrometer type detector A ₂ are Vc and Vd, the amplification factor Z ₂ in the closed loop control is (Td-Tc) / (Vd-Vc). The rotation speeds of a plurality of pairs of draft rollers Rb other than the pair of front draft rollers Rf are changed by a servo motor (not shown) that shifts each roller Rb through a differential device (not shown). . Of the command values sent from the speed control circuit C to each servo motor, the command value in open loop control is represented by [Z ₁ × (V ₁ −V ₂ )] (Equation 1).
Here, V ₁ is the current point output of the detector A ₁ , and V ₂ is the measurement start point output of the detector A ₁ . Similarly, the command value in the closed loop control is [Z ₂ × (V ₃ −V ₄ ) ×
Total draft] (equation 2) multiplied by the closed loop control integration constant K ₁ (equation 3), and the value (equation 2) multiplied by the closed loop control proportional constant K ₂ (equation 4) ). Where V ₃ is the current point output of detector A ₂ ,
V ₄ is the target output of detector A ₂ . Of the respective values expressed by the equations 1 to 4, the sum of the respective values expressed by the equations 1, 3 and 4 becomes the command value sent to the servo motor.

A control method of the sliver spot correction device P according to the present invention will be described with reference to FIGS. 1 and 5. If the sliver S supplied is pure spinning, the same coupling control as the conventional one is performed. If the sliver S to be supplied is mixed spinning, the second signal B ₂ (variation width of the cross-sectional thickness of the sliver S) output from the detector A ₂ on the outlet side is compared with the comparison circuit C.
₂ exceeds the preset comparison value. Then, the level discriminant closed loop control is performed.

The level discriminant closed loop control is composed of a control mainly including closed loop control and a closed loop control accompanied by level discrimination. First, the control mainly including the closed loop control will be described. As described above, in the case of mixed spinning, the signal B ₁ from the capacitance type detector A ₁ becomes unstable, and fine control cannot be performed. Therefore, it is necessary to correct the short cycle spots by the control mainly including the closed loop control. To this end, a draft method is adopted in which drafting is performed in the main draft zone, and the air micrometer type detector A ₂ is placed at a position as close as possible to the pair of front draft rollers Rf disposed on the exit side of the draft zone D. It is necessary to install it by making it as short as possible without sagging the piping tube for supplying air to the detector A ₂ . By doing so, if Shiteyare shorten the time in which the signal B ₂ from detector A ₂ is transmitted, the short cycle unevenness of the sliver S in control consisting mainly of closed-loop control can be modified to some extent. However, in the case where a spot with a very short wavelength such as one piece of the sliver S is generated, it cannot be corrected by the above method.

When a spot with a very short wavelength such as a break of one sliver S is generated, the closed loop control with the level discrimination is performed. Next, the closed loop control accompanied by this level discrimination will be described. As described above, in the case of mixed spinning, the signal B ₁ from the capacitance type detector A ₁ becomes unstable, and fine control cannot be performed. However, even in the case of blended spinning, if the sliver S has a large change, an approximate tendency can be grasped. Therefore, when the signal B ₁ from the detector A ₁ of the electrostatic capacitance type entered in the comparator circuit C _1, the signal B ₁
And the comparison value set in the comparison circuit C ₁ in advance.
That is, level discrimination is performed. When a spot with a very short wavelength such as a break of one sliver S is generated, the signal B
₁ exceeds the comparison value. Then, the command B ₃ is sent from the comparison circuit C ₁ to the speed control circuit C. This command B ₃ is different from the conventional signal B ₁ ′. By command B ₃ ,
A value obtained by summing the values expressed by the above-described expressions 1, 3, and 4 is sent to the servo motor. As a result, the rotational speeds of the servo motors (not shown) that shift the plurality of pairs of draft rollers Rb except the pair of front draft rollers Rf via the differential device (not shown) are changed for a predetermined time. , Patch correction is performed. Then, the control mainly based on the closed loop control is performed again.

In this embodiment, the comparison value set in advance in the comparison circuit C ₁ is described as being classified into two levels. However, this comparison value is classified into three or more levels. Is also possible. By performing control according to each level, finer control can be performed. In addition, the sliver spot correction device P of the present embodiment uses the signal B output from the detector A ₂ on the exit side.
₂ (variation width of sectional thickness of sliver S) is compared circuit C ₂
According to whether or not the sliver S to be supplied is a pure spinning or a mixed spinning, the optimum control method is automatically selected depending on whether or not the comparison value set in advance is exceeded. But,
It is also possible to manually select either the coupling control or the level discriminant closed loop control.

[0023]

The sliver spot correction apparatus according to the present invention automatically controls the sliver in either case because it performs the coupling control in the case of pure spinning and the closed loop control in the case of mixed spinning. It is possible to correct the spots. Further, in the case of blended spinning, even spots that cannot be corrected only by the control mainly based on the closed loop control, for example, spots with a very short wavelength such as one break of a sliver, can be corrected by the closed loop control accompanied by level discrimination.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a sliver spot correction device P according to the present invention.

FIG. 2 is a diagram showing a method of calculating an amplification factor Z ₁ .

FIG. 3 is a diagram showing a method of calculating an amplification factor Z ₂ .

FIG. 4 is a diagram showing a method of calculating a command value for a servo motor.

FIG. 5 is a flowchart showing a control process of the sliver spot correction device P according to the present invention.

FIG. 6 is a diagram showing conventional open loop control.

FIG. 7 is a schematic diagram of a capacitance type detector A ₁ .

FIG. 8 is a schematic view of a press-type detector A ₁ ′.

FIG. 9 is a diagram showing conventional closed loop control.

FIG. 10 is a diagram showing a change in sectional thickness of a sliver S in closed loop control.

FIG. 11 is a diagram showing conventional coupling control.

FIG. 12 is a view showing a mixed spinning.

[Explanation of symbols]

A ₁ : Cross-section thickness detector (open loop control) A ₂ : Cross-section thickness detector (closed loop control) B ₁ : First signal (open loop control) B ₂ : Second signal (closed loop control) C: Speed control circuit C ₁ : First comparison circuit (open loop control) C ₂ : Second comparison circuit (closed loop control) D: Draft zone K ₁ : Closed loop control integration constant (multiple control constants) K ₂ : Closed loop control proportionality constant (more control constants) P: sliver unevenness correction device Rb: back draft rollers (pairs of draft rollers) Rf: front drafting rollers (pairs of draft rollers) S: sliver Z _1, Z _2: amplification factor ( Multiple control constants)

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[Procedure amendment]

[Submission date] April 19, 1996

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] Fig. 6

[Correction method] Change

[Correction contents]

FIG. 6

Claims (3)

[Claims] 1. A detector for measuring a sectional thickness of a sliver supplied to a draft zone and outputting a first signal, a means for controlling a rotation speed of a plurality of pairs of draft rollers in the draft zone, and a draft zone. And a detector that outputs a second signal by measuring the cross-sectional thickness of the sliver that has passed through, and at least one of open loop control and closed loop control is performed by each of the detectors and the rotation speed control means. In the sliver spot correction apparatus for performing the above, the comparison value is preset in each comparison circuit to which the first and second signals are input, and the speed control circuit to which the command from each comparison circuit is input is input. Has a plurality of control constants set in advance, and when the second signal exceeds the comparison value set in advance in the second comparison circuit, the first signal is set in advance in the first comparison circuit. The sliver spot correction apparatus in a spinning machine, wherein level discriminant closed loop control is performed to compare the rotation speeds of a plurality of pairs of draft rollers based on the comparison result. 2. A plurality of comparison values are set in the first comparison circuit, and each control is performed according to a result of comparison of the first signal with the plurality of comparison values. The sliver spot correction device in the spinning machine according to claim 1. 3. The spinning machine according to claim 1, wherein either one of a joint control for simultaneously performing open loop control and closed loop control and a level discriminant closed loop control is automatically selected. Sliver spot correction device in.