JP5598412B2 - Tension control system, tension control method, and computer program - Google Patents

Description

  The present invention relates to a tension control system, a tension control method, and a computer program, and particularly suitable for use in controlling a tension applied to a metal strip passed through a process line using a bridle roll. It is.

In a process line that continuously performs cleaning, heating, cooling, plating, etc. on a metal strip such as a steel plate, a plurality of bridle rolls, pinch rolls, etc. are used to stably pass the metal strip in the process line. The drive rolls are arranged in series, and a predetermined tension is applied to the metal strip in the sheet passing through these rolls.
Conventionally, the following feedback control is performed in order to stably apply a tension to the metal strip in the plate. First, the tension applied to the metal strip is detected by a tension detector provided between two bridle rolls adjacent to each other. Next, a speed command such that this tension matches the target value is given to a speed controller that controls the rotational speed (number of rotations) of the upstream bridle roll of the two bridle rolls, The rotational speed of the upstream bridle roll is changed (see Patent Document 1).

JP 2006-247717 A

By the way, in the process line mentioned above, the tension | tensile_strength currently provided with respect to the metal strip may fluctuate | variate by disturbance, and the phenomenon (what is called fluttering) that the metal strip in a threading plate vibrates up and down may arise.
As a factor of such disturbance, for example, a cleaning device disposed on the upstream side of the process line can be cited. In this cleaning apparatus, in order to clean the surface of the metal strip, the cleaning liquid is continuously sprayed onto the metal strip by the nozzle, and is rotated by the brush roll so as to be opposite to the plate passing direction of the metal strip. Thereafter, in order to prevent the cleaning liquid adhering to the surface of the metal strip from being taken out to a subsequent process, a draining roll (Ringer roll) is pressed against the front side and the back side of the metal strip to which the cleaning liquid has adhered. Thereby, the cleaning liquid adhering to the surface of the metal strip is removed.

  By the way, since the metal strips connected to each other in the longitudinal direction are welded to each other in the longitudinal direction, there is a possibility that the metal strip may be broken when a brush roll is pressed against the welded portion. For this reason, in the said welding part, the reduction to the metal strip by a brush roll is open | released. In this way, when the brush roll is released from the squeezed state, the tension in the metal strip fluctuates rapidly, and this sudden fluctuation in tension propagates downstream in the process line. When such a rapid fluctuation in tension propagates to the downstream side of the process line, for example, the desired annealing cannot be performed in the heating furnace, which is a process on the downstream side of the process line, and the product quality deteriorates. There is a risk that the metal strip may break or the metal strip may be broken.

  However, in the conventional technique described above, since feedback control is performed, the response time of the control is delayed as compared with the variation in tension. Therefore, the above-described conventional technique has a problem that it is difficult to sufficiently suppress a rapid change in tension caused by the reduction and release of the brush roll of the above-described cleaning device.

  The present invention has been made in view of such a problem, and suppresses a rapid fluctuation in tension generated in a metal strip passing through a process line, and stably applies tension to the metal strip. The purpose is to do.

  The tension control system of the present invention is a tension control system for controlling the tension applied to a metal strip passing through a process line by using at least three bridle rolls adjacent to each other. First and second tension detection means for detecting actual tension values, which are values of tension applied to the metal strip, between two bridle rolls adjacent to each other among the rolls; The actual tension value detected by the first tension detecting means is set to the tension setting according to a tension deviation which is a deviation between the actual tension value detected by the first tension detecting means and a preset tension setting value. Speed change value deriving means for deriving a speed change value with respect to a preset plate passing speed reference value so as to be equal to the value, and the plate changing speed reference value is converted to the speed change value. Speed command value deriving means for deriving a speed command value changed according to the value, and tension fluctuation derivation for deriving a time differential value of the actual tension value, which is a time derivative of the actual tension value detected by the second tension detecting means. Means, a speed command correction value deriving means for deriving a correction value for the speed command value in accordance with a time differential value of the actual tension derived by the tension fluctuation deriving means, and a speed command value deriving means. Among the two bridle rolls adjacent to each other with the correction means for correcting the speed command value using the correction value derived by the speed command correction value deriving means, and the first tension detection means, Speed control means for controlling the rotational speed of the motor that drives the relatively upstream bridle roll based on the speed command value corrected by the correction means, and the speed The command correction value deriving means derives a correction value for the speed command value so as to decrease the rotational speed of the bridle roll when the sign of the time differential value of the tension result is positive, and the tension result When the sign of the time differential value is negative, a correction value for the speed command value is derived so as to increase the rotational speed of the bridle roll.

Tension control method of the present invention, a process line to the metal strip to be Tsuban, a tension control method for controlling the tension applied by using at least three bridle rolls adjacent to each other, said three bridle First and second tension detecting steps for detecting actual tension values, which are tension values applied to the metal strip, between two bridle rolls adjacent to each other among the rolls; The actual tension value detected by the first tension detection step is set to the tension setting according to the tension deviation that is a deviation between the actual tension value detected by the first tension detection step and the preset tension setting value. A speed change value deriving step for deriving a speed change value with respect to a preset plate passing speed reference value so as to be equal to the value, and the plate passing speed reference value according to the speed change value. A speed command value deriving step for deriving the changed speed command value, and a tension variation deriving step for deriving a time differential value of the actual tension value, which is a value obtained by temporally differentiating the actual tension value detected by the second tension detection step A speed command correction value deriving step for deriving a correction value for the speed command value according to a time differential value of the actual tension value derived by the tension variation deriving step, and a speed command derived by the speed command value deriving step A correction step of correcting the value using the correction value derived by the speed command correction value derivation step, and a relative value of two bridle rolls adjacent to each other with the first tension detection step interposed therebetween. And a speed control step for controlling the rotational speed of the motor that drives the upstream bridle roll based on the speed command value corrected by the correction step, and the speed command correction The deriving step derives a correction value for the speed command value so as to reduce the rotational speed of the bridle roll when the sign of the time differential value of the actual tension is positive, When the sign of the value is negative, a correction value for the speed command value is derived so as to increase the rotational speed of the bridle roll.

  The computer program according to the present invention applies a tension applied to a metal strip that passes through a process line by using at least three bridle rolls adjacent to each other, and two of the three bridle rolls adjacent to each other. A computer program for causing a computer to execute control using actual tension values detected by first and second tension detecting means respectively arranged between two bridle rolls, wherein the first tension The actual tension value detected by the first tension detecting means is equal to the tension setting value in accordance with a tension deviation that is a deviation between the actual tension value detected by the detecting means and a preset tension setting value. A speed change value derivation step for deriving a speed change value with respect to a preset plate speed reference value, and the plate speed A speed command value deriving step for deriving a speed command value obtained by changing the quasi-value by the speed change value, and a time differential value of the actual tension value which is a value obtained by differentiating the actual tension value detected by the second tension detecting means with respect to time. A tension variation deriving step for deriving a speed command, a speed command correction value deriving step for deriving a correction value for the speed command value according to a time differential value of the actual tension derived by the tension variation deriving step, and the speed command value A correction step of correcting the speed command value derived in the derivation step using the correction value derived in the speed command correction value derivation step, and the speed command value corrected in the correction step as the first tension. Out of two bridle rolls adjacent to each other with the detection means in between, output to the speed control means for controlling the rotational speed of the motor that drives the relatively upstream bridle roll. And an output step for performing processing for the speed command correction value derivation step, wherein the speed command correction value derivation step reduces the rotational speed of the bridle roll when the sign of the time differential value of the actual tension is positive. As described above, when the correction value for the speed command value is derived and the sign of the time differential value of the actual tension is negative, the correction value for the speed command value is increased so as to increase the rotational speed of the bridle roll. Is derived.

  According to the present invention, the tension detected by the first tension detecting means according to the tension deviation which is the deviation between the actual tension value detected by the first tension detecting means and the preset tension setting value. Deriving a speed change value with respect to a preset feeding speed reference value so that the actual value becomes equal to the tension setting value, and deriving a speed command value obtained by changing the passing speed reference value using the speed change value. To do. A correction value for the speed command value is derived according to the time differential value of the actual tension value, which is a value obtained by differentiating the actual tension value detected by the second tension detecting means with respect to time. Then, the speed command value is corrected using the correction value, and based on the corrected speed command value, of the two bridle rolls adjacent to each other with the first tension detecting means interposed therebetween, Controls the rotational speed of the motor that drives the upstream bridle roll. At this time, if the sign of the time differential value of the actual tension is positive, a correction value for the speed command value is derived so as to decrease the rotational speed of the bridle roll, and the sign of the time differential value of the actual tension is negative. If so, a correction value for the speed command value is derived so as to increase the rotational speed of the bridle roll. Therefore, when a sudden fluctuation in tension occurs as a disturbance, the threading speed is adjusted so as to absorb the fluctuation more quickly than when the speed command value is not corrected using the correction value for the speed command value. be able to. Therefore, it is possible to suppress a sudden fluctuation in tension generated in the metal strip in the plate passing through the process line, and to stably apply the tension to the metal strip.

It is a figure which shows the 1st example of a structure of the tension control system which controls the tension | tensile_strength of the steel plate which passes a process line. It is a figure which shows an example of a functional structure of a tension fluctuation compensator. It is a figure which shows notionally an example of the content of the table which has memorize | stored the code | symbol and absolute value of the time differential value of a tension | tensile_strength record, and a coefficient in correlation with each other. It is a flowchart which shows embodiment of this invention and demonstrates an example of operation | movement of a tension fluctuation compensator. It is a figure which shows the relationship between "the actual tension value and the rotational speed of a bridle roll" and "time" in the vicinity before and after releasing the brush roll. It is a figure which shows the 2nd example of a structure of the tension control system which controls the tension | tensile_strength of the steel plate which passes a process line.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
(First embodiment)
First, a first embodiment of the present invention will be described.
FIG. 1 is a diagram illustrating an example of a configuration of a tension control system that controls the tension of a steel plate passing through a process line.

<Process line>
First, the process line will be described with reference to FIG.
The process line includes a cleaning device 111, bridle rolls 112a to 112c, and roll drive motors 113a to 113f. In FIG. 1, only the equipment necessary for explaining the operation of the tension control system is shown among the equipment provided in the process line. Therefore, in addition to this, the process line is equipped with facilities necessary for manufacturing products (including intermediate products). For example, if the process line is a process line for producing a galvanized steel sheet, a heating furnace or the like is provided in the process line (on the downstream side of the bridle roll 112c).
In FIG. 1, a steel plate (metal strip) S is passed through from the left to the right (the direction of the arrow marked on the steel plate S) as viewed in the figure.

[Cleaning device 111]
The cleaning device 111 is for cleaning the steel sheet S. For example, the cleaning device 111 does not take out the cleaning liquid adhering to the surface of the steel plate and the nozzle that injects the cleaning liquid, the brush roll rotating in the direction opposite to the sheet passing direction, and the cleaning process in order to ensure the cleaning ability. And a draining roll (ringer roll).
The rotating brush roll and draining roll are pressed against (pressed down) the steel sheet S passed through the cleaning device. Thereby, the cleaning liquid adhering to the steel sheet S is removed. Moreover, about the welding location of the steel plate S, in order to prevent the fracture | rupture of the steel plate S, it is made not to reduce a brush roll. That is, the brush roll is opened slightly before the welded portion of the steel plate S reaches the reduction position of the brush roll. Thus, the brush roll repeats the reduction and release.

[Bridal Roll 112]
The bridle rolls 112a, 112b, and 112c are rolls for passing the steel plate S. Tension is applied to the steel sheet S that passes between two bridle rolls 112 (briddle rolls 112a and 112b and bridle rolls 112b and 112c) adjacent to each other. The bridle rolls 112a, 112b, and 112c include two drive rolls 114a and 114b, 114c and 114d, and 114e and 114f, respectively. The bridle rolls 112a, 112b, and 112c are also provided with other devices (such as a housing) other than the drive rolls 114a and 114b, 114c and 114d, and 114e and 114f. Further, the number of bridle rolls 112a, 112b, 112c arranged in the process line is not limited to three, and more than three bridle rolls 112 may be arranged in the process line.

[Roll drive motor 113]
The roll drive motors 113a, 113b, 113c, 113d, 113e, and 113f are motors for rotating the drive rolls 114a and 114b, 114c and 114d, and 114e and 114f, respectively. The roll drive motors 113a, 113b, 113c, 113d, 113e, and 113f are rotational speeds (number of rotations) based on speed commands from motor speed controllers (ASR) 125a, 125b, 125c, 125d, 125e, and 125f, which will be described later. Rotate.

<Tension control system>
The tension control system adjusts the rotation speed of the roll drive motor 113 so that fluctuations in the tension of the steel sheet S passing between the two bridle rolls 112 adjacent to each other are suppressed.
The tension control system includes tension detectors 121a to 121c, subtractors 122a to 122c, tension controllers (ATR) 123a to 123c, adders 124a to 124c, motor speed controllers (ASR) 125a to 125f, A tension fluctuation compensator 126.

[Tension detector 121]
The tension detectors 121a, 121b, and 121c are respectively arranged between the bridle roll 112a and the bridle roll 112b, between the bridle roll 112b and the bridle roll 112c, and between the bridle roll 112c and the bridle roll 112c (not shown). it is intended to measure the tension actual value F _m which is applied to the steel sheet S to Tsuban between.
[Subtractor 122]
Subtractor 122a, 122b, 122c, respectively, from the tension setting value F _r that is set in advance, the tension detector 121a, 121b, by subtracting the measured tension actual value F _m by 121c, the tension deviation (F _r -F _m ). The tension set value F _r is a tension value for optimally passing the steel sheet S. Note that the tension set value F _r differs (but may be the same) in a section (a region between two bridle rolls 112 adjacent to each other).

[Tension controller 123]
In the tension controllers 123a, 123b, and 123c, the actual tension value F _m becomes equal to the tension set value F _r in accordance with the tension deviation (F _r −F _m ) derived by the subtractors 122a, 122b, and 122c, respectively. as described above, to derive the speed change value [Delta] V _r for a preset sheet passing speed reference value V _r. The tension controllers 123a, 123b, and 123c are realized by using, for example, a P controller or a PI controller.
[Adder 124]
The adders 124a, 124b, and 124c respectively add the speed change value ΔV _r derived by the tension controllers 123a, 123b, and 123c and the sheet feeding speed reference value V _r to obtain a speed command value (V _r + ΔV). _r ) is derived.

[Motor speed controller 125]
Each of the motor speed controllers 125a and 125b receives the speed command value (V _r + ΔV _r ) derived by the adder 124a, and the roll drive motor 113a based on the input speed command value (V _r + ΔV _r ). , 113b is controlled. In the present embodiment, the bridle roll 112a is a speed reference roll. Thus, the motor speed controller 125a · 125b, respectively, through plate speed of the steel sheet S is always such that the sheet passing speed reference value V _r, controls the rotational speed of the roll driving motor 113a, 113b.

The motor speed controllers 125e and 125f also receive the speed command value (V _r + ΔV _r ) derived by the adder 124c, and roll drive based on the input speed command value (V _r + ΔV _r ). The rotational speed of the motors 113e and 113f is controlled.
On the other hand, the motor speed controllers 125c and 125d respectively have a speed command value (V _r + ΔV _r ) derived by the adder 124b and a speed command correction value ΔV _r ′ derived by a tension fluctuation compensator 126 described later. Is input (final) speed command value (V _r + ΔV _r + ΔV _r ′), and based on the input speed command value (V _r + ΔV _r + ΔV _r ′), the roll drive motors 113c and 113d Control the rotation speed.

[Tension fluctuation compensator 126]
The tension fluctuation compensator 126 is a tension detector 121a disposed between two bridle rolls 112a, 112b adjacent to each other on the relatively upstream side among the three bridle rolls 112a, 112b, 112c adjacent to each other. rate of in type the measured tension actual value F _m, the two bridle roll 112a, among 112b, for correcting the speed command value for the bridle roll 112b on the relatively downstream side (V _r + ΔV _r) A command correction value ΔV _r ′ is derived. The speed command correction value ΔV _r ′ is used for the bridle roll 112b (driving rolls 114c and 114d) so as to suppress a rapid change in tension generated when the brush roll of the cleaning device 111 on the upstream side is opened. This is for adjusting the rotation speed. Thus, the tension fluctuation compensator 126 is a feedforward compensator. In the following description, “abrupt fluctuations in tension generated when the brush roll of the cleaning device 111 is opened” is referred to as “tension disturbance” as necessary.

  FIG. 2 is a diagram illustrating an example of a functional configuration of the tension fluctuation compensator 126. The hardware of the tension fluctuation compensator 126 is realized by using, for example, a PLC (Programmable Logic Controller) or a computer (for example, a personal computer). Then, the function of the tension fluctuation compensator 126 is realized by loading computer software for executing the processing shown in the flowchart of FIG.

In FIG. 2, the tension fluctuation compensator 126 includes a differentiating unit 126a, a blocking unit 126b, a multiplying unit 126c, a speed converting unit 126d, and an adding unit 126e.
[[Differentiator 126a]]
Differentiating section 126a has, entering the tension actual value F _m measured by the tension detector 121a, a function as a differentiator for differentiating the tension actual value F _m time. In the following description, “value obtained by time differentiation of actual tension value F _m (dF _m / dt)” is referred to as “time differential value of actual tension” as necessary.

[[Blocking part 126b]]
The shut-off unit 126b removes components unrelated to the tension disturbance, such as a noise component, from the signal of the time differential value of the actual tension obtained by the differentiating unit 126a.
Specifically, the blocking unit 126b has a function as a filter that blocks high-frequency components of the time differential value signal of the actual tension obtained by the differentiating unit 126a. Note that the frequency of the signal for blocking the passage is appropriately set from the viewpoint of removing components unrelated to the tension disturbance.
Further, the blocking unit 126b has a function of selecting either the time differential value of the previous actual tension or the time differential value of the current actual tension.

In order to make this selection, the blocking unit 126b first stores the time differential value of the actual tension and the acquisition time (for the next calculation).
Next, the blocking unit 126b calculates a value obtained by subtracting the time differential value of the previous tension result from the time differential value of the current tension result from the time when the time differential value of the current tension result is acquired. The tension change speed amount is calculated by dividing the time at which the differential value was acquired by the subtracted value. That is, the tension change speed amount is expressed by the following equation (1).
Tension change speed amount = (Time differential value of actual tension result-Time differential value of previous tension result) ÷ (Time when time differential value of actual tension result was acquired-Time differential value of previous actual tension value was acquired (Time) (1)

Next, the blocking unit 126b determines whether or not the absolute value of the tension change speed amount exceeds a threshold value. If the sign of the tension change speed amount is positive (+), the time differential value of the current actual tension is increased with respect to the time differential value of the previous actual tension. On the other hand, if the sign of the tension change speed amount is negative (−), the time differential value of the current actual tension is decreased with respect to the time differential value of the previous actual tension. Here, the actual tension value F _m may instantaneously take a maximum value (or a minimum value) due to the influence of noise or the like. Therefore, in the present embodiment, it is determined whether or not the actual tension value F _m instantaneously takes the maximum value (or minimum value) by determining whether or not the absolute value of the tension change speed amount exceeds the threshold value. Like to do.

Blocking section 126b determines that the absolute value of the variation in tension speed amount exceeds the threshold value, determines that the tension actual value F _m is taken instantaneously maximum value (or minimum value), the time of this tension results Select the time differential value of the previous actual tension without adopting the differential value. This is because, in such a case, if the time differential value of the actual tension is selected, the control becomes unstable, and on the contrary, it may cause a disturbance. However, when the time differential value of the previous actual tension value also exceeds the threshold value, the latest one is selected from the time differential values of the previous tension result. In other words, when the interruption unit 126b determines that the absolute value of the tension change speed amount exceeds the threshold value, the interruption unit 126b selects the latest one of the time differential values of the already selected tension results.
On the other hand, when it is determined that the absolute value of the tension change speed amount does not exceed the threshold value, the blocking unit 126b selects the time differential value of the current actual tension.
The threshold value to be compared with the absolute value of the tension change speed amount is appropriately set from the viewpoint of removing a component unrelated to the tension disturbance.

[[Multiplier 126c]]
The multiplication unit 126c extracts the coefficient K corresponding to the sign and the absolute value of the “time differential value of actual tension” selected by the blocking unit 126b.
FIG. 3 is a diagram conceptually illustrating an example of the contents of a table in which the sign and absolute value of the time differential value of the actual tension and the coefficient K are stored in association with each other.

In the present embodiment, the tension fluctuation compensator 126 stores a table 300 shown in FIG. 3 in advance. The multiplication unit 126c refers to the table 300, and extracts the coefficient K corresponding to the sign and value of the “time differential value of the actual tension” selected by the blocking unit 126b.
Here, when the sign of the time differential value of the actual tension is positive (+), it is necessary to decelerate the rotational speed of the bridle roll 112b, which is the rotational speed control target. Therefore, as shown in FIG. 3, in this embodiment, when the sign of the time differential value of the actual tension is positive (+), the sign of the coefficient K is negative (−).

  On the other hand, when the sign of the time differential value of the actual tension is negative (−), it is necessary to increase the rotational speed of the bridle roll 112b that is the target of the rotational speed control. Therefore, when the sign of the time differential value of the actual tension is negative (−), the sign of the coefficient K is positive (+). In the present embodiment, the absolute value of the coefficient K is increased as the absolute value of the time differential value of the actual tension is increased.

Next, the multiplication unit 126c multiplies the “time differential value of actual tension” selected by the blocking unit 126b by the coefficient K extracted as described above. In the following description, “the value obtained by multiplying the time differential value of the actual tension by the coefficient K” is referred to as “the coefficient multiplication value of the time differential of the actual tension” as necessary. The coefficient multiplication value of the time derivative of the actual tension is expressed by the following equation (2).
Coefficient multiplication value of time differential of actual tension = K x (Time differential value of actual tension) (2)
In FIG. 3, for convenience of explanation, the sign and absolute value of “time differential value of actual tension” are stored in the table 300. Instead of this, “time differential value of actual tension” itself ( The value including the sign) may be stored in the table 300.

[[Speed conversion unit 126d]]
The “tension actual time coefficient multiplication value” calculated by the multiplication unit 126 c corresponds to the tension fluctuation of the steel sheet S. Speed conversion unit 126d is a "coefficient multiplication value of the time derivative of the tension actual value F _m" corresponding to the variation of the tension, is converted to the variation of the sheet passing speed of the steel sheet S. For this reason, in this embodiment, the speed conversion unit 126d divides the “multiplier value of the time derivative of the actual tension” by the diameters of the drive rolls 114c and 114d of the bridle roll 112b that is the target of rotation speed control. A speed command correction value ΔV _r ′ is calculated. That is, the speed conversion unit 126d calculates the speed command correction value ΔV _r ′ by calculating the following equation (3).
Speed command correction value ΔV _r ′ = (coefficient multiplication value of time differential of actual tension) / (diameter of driving rolls 114c and 114d) (3)
Here, since the variation in the tension of the steel plate S is approximated to the variation in the plate passing speed of the steel plate S, it is not necessary to match the unit of the speed command correction value ΔV _r ′ with the unit of the speed. Absent.

[[Adder 126e]]
The adding unit 126e has a function as an adder that adds the speed command correction value ΔV _r ′ derived by the speed converting unit 126d to the speed command value (V _r + ΔV _r ) derived by the adder 124b. This added value is output to the motor speed controllers 125c and 125d as a (final) speed command value (V _r + ΔV _r + ΔV _r ′).

<Operation flowchart>
Next, an example of the operation of the tension fluctuation compensator 126 will be described with reference to the flowchart of FIG.
First, in step S401, the differential unit 126a determines whether or not there is an input tension actual value F _m measured by the tension detector 121a. As a result of the determination, if you have not entered the tension actual value F _m ends the processing according to the flow chart in FIG 4.

On the other hand, when the actual tension value _Fm is input, the process proceeds to step S402. In step S402, the differential unit 126a, the tension actual value F _m which is input by derivative time in step S401, calculates the time differential value of tension results of (dF _m / dt).
Next, in step S403, the blocking unit 126b blocks the high frequency component of the time differential value signal of the actual tension obtained by the differentiating unit 126a.
Next, in step S404, the blocking unit 126b stores a time differential value of the actual tension. And the interruption | blocking part 126b calculates (1) Formula, and calculates the tension | tensile_strength change speed amount.

Next, in step S405, the blocking unit 126b determines whether or not the absolute value of the tension change speed amount calculated in step S404 has exceeded a threshold value. As a result of the determination, if the absolute value of the tension change speed amount does not exceed the threshold value, the process proceeds to step S406. In step S406, the blocking unit 126b selects the time differential value of the current actual tension (the latest differential time value calculated in step S402).
On the other hand, if the absolute value of the tension change speed amount exceeds the threshold value, the process proceeds to step S407. In step S407, the blocking unit 126b selects the latest one of the time differential values of the actual tension selected in step S406 so far.

When the time differential value of the actual tension is selected as described above, the process proceeds to step S408. In step S408, the multiplication unit 126c extracts the coefficient K corresponding to the sign and absolute value of the “time differential value of actual tension” selected in step S406 or S407 with reference to the table 300.
Next, in step S409, the multiplying unit 126c multiplies the “time differential value of actual tension” selected in step S406 or S407 by the coefficient K extracted in step S408, to obtain “the time differential of actual tension”. "Coefficient multiplication value" is calculated.

Next, in step S410, the speed conversion unit 126d uses the diameters of the drive rolls 114c and 114d of the bridle roll 112b that is the object of rotation speed control for the “coefficient multiplication value of the actual time of tension” calculated in step S408. By dividing, the speed command correction value ΔV _r ′ is derived.
Next, in step S411, the adding unit 126e adds the speed command correction value ΔV _r ′ derived in step S410 to the speed command value (V _r + ΔV _r ) derived by the adder 124b (final). N) A speed command value (V _r + ΔV _r + ΔV _r ′) is derived.
Next, in step S412, the adding unit 126e outputs the speed command value (V _r + ΔV _r + ΔV _r ′) to the motor speed controllers 125c and 125d. The above steps S401 to S412 are repeated and executed. The motor speed controllers 125c and 125d control the rotational speeds of the roll drive motors 113c and 113d based on the speed command value (V _r + ΔV _r + ΔV _r ′).

<Example>
Next, examples of the present invention will be described.
Here, when the process line shown in FIG. 1 is operated under the following conditions, the actual tension value F _m detected by the tension detectors 121a and 121b and the bridle roll 112b before and after the brush roll of the cleaning device 111 is opened. We investigated how the rotation speed of the machine changed. The tension control system shown in FIG. 1 is used as the tension control system of this embodiment, and the tension control system shown in FIG. 1 is omitted from the tension control system shown in FIG. A tension control system was used.

Steel sheet: Electrical steel sheet (width = 1213 [mm], thickness = 0.27 [mm])
Line speed: 50 [m / min]
Tension set value F _r : 2300 [N]
The line speed and the tension set value F _r are values in the sections between the bridle rolls 112a and 112b, respectively.

FIG. 5 is a diagram showing the relationship between “the measured values of the tension detectors 121a and 121b (actual tension values F _m ) and the rotational speed of the bridle roll 112b” and “time” in the vicinity before and after the brush roll is opened. . FIG. 5A shows the relationship in this embodiment, and FIG. 5B shows the relationship in the comparative example.
In FIG. 5, graphs 501a and 501b indicate the rotational speed of the bridle roll 112b. A graph 502a, 502b indicates a tension actual value F _m which is detected by the tension detector 121a, graph 503a, 503b indicates a tension actual value F _m which is detected by the tension detector 121b.

The scale on the horizontal axis in FIG. 5 is 30 [second / 1 square]. Further, the scale of the tension on the vertical axis in FIG. 5 is 250 [N / 1 square]. Further, the scale of the rotational speed on the vertical axis in FIG. 5 is 4 [rotations / minute / 1 square].
In FIG. 5, broken lines 504a and 504b represent the timing at which the brush roll of the cleaning device 111 is opened (the timing at which a tension disturbance occurs).

As shown in the graph 503a of FIG. 5 (a), in this example, "variation width Wa due to the tension disturbance" tension actual value F _m which is detected by the tension detector 121b is less than 100 [N] There, and, after the tension disturbance occurs, the convergence time Ta until the tension actual value F _m which is detected by the tension detector 121b is converged to a constant value, was about 20 seconds. On the other hand, as shown in the graph 503b of FIG. 5B, in the comparative example, the “variation width Wa caused by the tension disturbance” of the actual tension value F _m detected by the tension detector 121b is 500 [N And the convergence time Ta from the occurrence of the tension disturbance until the actual tension value F _m detected by the tension detector 121b converges to a constant value is about 60 seconds.
Thus, it can be seen that both the fluctuation range W and the convergence time T are smaller in this embodiment than in the comparative example, and the effectiveness of tension control is higher.

<Summary>
As described above, in the present embodiment, based on the tension actual value F _m measured by the tension detector 121a, when the fluctuation of the sudden tension (tension disturbance) is determined to have occurred, of the sudden tension A speed command value (V _r + ΔV _r + ΔV _r ′) obtained by deriving a speed command correction value ΔV _r ′ as a speed command correction value ΔV _r ′ and adding the speed command correction value ΔV _r ′ according to the change. ) To the motor speed controllers 125c and 125d that control the drive rolls 114c and 114d that are closest to the downstream side with respect to the tension detector 121a. Therefore, even if a sudden tension fluctuation (tension disturbance) occurs, the rotational speeds of the drive rolls 114c and 114d can be corrected as quickly as possible (without delay) so as to absorb the tension fluctuation. .

On the other hand, as in the conventional technique in which the tension fluctuation compensator 126 is not provided, the drive rolls 114c and 114d closest to the downstream side with respect to the tension detector 121a according to the tension deviation (F _r −F _m ). The method of passively correcting the rotation speed exhibits an effect of suppressing the fluctuation of the tension against the fluctuation of the low frequency (long change cycle) tension, but the response to the fluctuation of the tension is slow. For this reason, the effect of suppressing the fluctuation | variation of the said tension | tensile_strength is not exhibited with respect to the fluctuation | variation of the tension | tensile_strength (short period of a change). That is, when the tension disturbance occurs, the method of the present embodiment can stably apply the tension to the steel sheet S than the conventional method in which the tension fluctuation compensator 126 is not provided. Stable plate operation can be continued stably.

<Modification>
In the present embodiment, a case where the metal strip is a steel plate will be described as an example. However, the metal strip is not limited to a steel plate. For example, other metal strips such as aluminum and copper may be used.
Further, the cause of the tension disturbance is not limited to the release of the brush roll of the cleaning device 111 but is different depending on the process line.
In the present embodiment, the coefficient K corresponding to the sign and value of the “time differential value of actual tension” selected by the blocking unit 126b is extracted. However, this is not always necessary. For example, the coefficient K may be extracted in accordance with the sign (only) of “time differential value of actual tension” selected by the blocking unit 126b. In this case, one of the two coefficients K is extracted according to the sign of the time differential value of the actual tension.
In this embodiment, the multiplication unit 126c multiplies the “time differential value of the actual tension” by the “coefficient K” to derive the “multiply value of the time differential of the actual tension”, and the speed conversion unit 126d outputs the “result of tension”. The “speed command correction value ΔV _r ′” was derived by dividing the “time differential coefficient multiplication value of” by the “diameter of the driving rolls 114 c and 114 _d ”. However, this is not always necessary. For example, “speed command correction value ΔV _r ′” may be derived by multiplying “time differential value of actual tension” by a value obtained by dividing “coefficient K” by “diameter of driving rolls 114 c and 114 _d ”. Good.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. In the first embodiment described above, the speed reference roll is the bridle roll 112a, and the speed command value (V _r + ΔV) for the bridle roll 112b that is relatively downstream of the two adjacent bridle rolls 112a and 112b. _{The case where r} ) is corrected by the speed command correction value ΔV _r ′ derived by the tension fluctuation compensator 126 has been described as an example. In contrast, in the present embodiment, the speed reference roll is the bridle roll 112b, and the speed command value (V _r + ΔV) for the bridle roll 112a that is relatively upstream of the two adjacent bridle rolls 112a and 112b. _{A case where r} ) is corrected by the speed command correction value ΔV _r ′ derived by the tension fluctuation compensator 126 will be described as an example. Thus, the present embodiment and the first embodiment are mainly different in the place where the tension fluctuation compensator 126 is applied. Therefore, in the description of the present embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals as those in FIGS.

FIG. 6 is a diagram illustrating an example of a configuration of a tension control system that controls the tension of a steel plate passing through a process line.
As shown in FIG. 6, in the present embodiment, the tension fluctuation compensator 126 includes two bridle rolls 112b and 112c that are adjacent to each other on the relatively downstream side among the three adjacent bridle rolls 112a and 112b. The actual tension value F _m measured by the tension detector 121b disposed between them is input, and the speed command value (V _r + ΔV _r) for the bridle roll 112a located on the most upstream side among the three bridle rolls 112b to 112c. ) To obtain a speed command correction value ΔV _r ′. The processing contents of the tension fluctuation compensator 126 are the same as those described in the first embodiment.
Even if it does as mentioned above, the effect equivalent to the effect demonstrated in 1st Embodiment can be acquired.
Also in this embodiment, various modifications described in the first embodiment can be applied.

<Relationship with Claims>
At least three bridle rolls adjacent to each other are realized by using, for example, bridle rolls 112a, 112b, and 112c.
In the first embodiment, the first tension detection unit is realized by using, for example, a tension detector 121b, and in the second embodiment, for example, by using a tension detector 121a.
In the first embodiment, the second tension detection means is realized by using, for example, a tension detector 121a, and in the second embodiment, for example, by using a tension detector 121b.
In the first embodiment, the speed change value deriving means is realized by using, for example, a subtractor 122b, a tension controller 123b, and an adder 124b. In the second embodiment, the subtractor 122a, the tension controller This is realized by using 123a and an adder 124a. Here, the speed change value corresponds to the speed change value ΔV _r , for example.
The speed command value deriving means is realized by using the adder 124b in the first embodiment, and is realized by using the adder 124a in the second embodiment. Here, it corresponds to a speed command value, for example, a speed command value (V _r + ΔV _r ).
The tension fluctuation deriving means is realized, for example, by using the differentiating unit 126a of the tension fluctuation compensator 126.
The speed command correction value deriving unit is realized by using, for example, the multiplication unit 126c of the tension fluctuation compensator 126. Here, this is realized by using a correction value for the speed command value, for example, a speed command correction value ΔV _r ′.
The correcting means is realized by using, for example, the adding unit 126e of the tension fluctuation compensator 126.
The speed control means is realized by using the motor speed controllers 125c and 125d in the first embodiment, and is realized by using the motor speed controllers 125a and 125b in the second embodiment.
Of the three bridle rolls, two bridle rolls adjacent to each other on the relatively downstream side are realized by using, for example, bridle rolls 112b and 112c.
Of the three bridle rolls, two bridle rolls that are adjacent to each other on the relatively upstream side are realized by using, for example, bridle rolls 112a and 112b.

The embodiment of the present invention described above can be realized by a computer executing a program. Further, a means for supplying the program to the computer, for example, a computer-readable recording medium such as a CD-ROM in which such a program is recorded, or a transmission medium for transmitting such a program may be applied as an embodiment of the present invention. it can. A program product such as a computer-readable recording medium that records the program can also be applied as an embodiment of the present invention. The programs, computer-readable recording media, transmission media, and program products are included in the scope of the present invention.
In addition, the embodiments of the present invention described above are merely examples of implementation in carrying out the present invention, and the technical scope of the present invention should not be construed as being limited thereto. Is. That is, the present invention can be implemented in various forms without departing from the technical idea or the main features thereof.

DESCRIPTION OF SYMBOLS 111 Cleaning apparatus 112 Bridle roll 113 Roll drive motor 114 Drive roll 121 Tension detector 122 Subtractor 123 Tension controller 124 Adder 125 Motor speed controller 126 Tension fluctuation compensator 126a Differentiation part 126b Blocking part 126c Multiplication part 126d Speed conversion part 126e Adder

Claims (11)

A tension control system for controlling tension applied to metal strips passing through a process line using at least three bridle rolls adjacent to each other;
First and second tension detecting means for detecting an actual tension value, which is a value of tension applied to the metal strip, between two adjacent bridle rolls among the three bridle rolls. When,
In accordance with a tension deviation that is a deviation between a tension actual value detected by the first tension detecting means and a preset tension setting value, the actual tension value detected by the first tension detecting means is Speed change value deriving means for deriving a speed change value with respect to a preset plate speed reference value so as to be equal to the tension setting value;
Speed command value deriving means for deriving a speed command value obtained by changing the plate passing speed reference value by the speed change value;
Tension variation deriving means for deriving a time differential value of the actual tension value, which is a value obtained by temporally differentiating the actual tension value detected by the second tension detecting unit;
Speed command correction value deriving means for deriving a correction value for the speed command value according to the time differential value of the actual tension obtained by the tension fluctuation deriving means;
Correction means for correcting the speed command value derived by the speed command value deriving means using the correction value derived by the speed command correction value deriving means;
A speed command value obtained by correcting the rotational speed of the motor that drives the relatively upstream bridle roll among the two bridle rolls adjacent to each other with the first tension detecting means interposed therebetween, corrected by the correcting means. Speed control means for controlling based on
The speed command correction value deriving means derives a correction value for the speed command value so as to decrease the rotational speed of the bridle roll when the sign of the time differential value of the actual tension is positive. When the sign of the time differential value of the actual tension is negative, a correction value for the speed command value is derived so as to increase the rotational speed of the bridle roll. The first tension detecting means is a tension result which is a value of a tension applied to the metal strip between two bridle rolls adjacent to each other on the relatively downstream side among the three bridle rolls. Detect the value,
The second tension detecting means is a tension result that is a value of a tension applied to the metal strip between two bridle rolls adjacent to each other on the relatively upstream side among the three bridle rolls. The tension control system according to claim 1, wherein a value is detected. The first tension detecting means is a tension result that is a value of a tension applied to the metal strip between two bridle rolls adjacent to each other on the relatively upstream side of the three bridle rolls. Detect the value,
The second tension detecting means is a tension result that is a value of a tension applied to the metal strip between two bridle rolls adjacent to each other relatively downstream of the three bridle rolls. The tension control system according to claim 1, wherein a value is detected.   The speed command correction value deriving unit uses a value obtained by multiplying the time differential value of the actual tension value by a coefficient corresponding to the sign of the time differential value of the actual tension value derived by the tension fluctuation deriving unit. The tension control system according to any one of claims 1 to 3, wherein a correction value is derived.   The speed command correction value deriving means is a value obtained by multiplying the time differential value of the actual tension value by the sign of the time differential value of the actual tension value derived by the tension fluctuation deriving means and a coefficient corresponding to the absolute value. The tension control system according to claim 4, wherein the tension control system is derived as a correction value for. A tension control method for controlling a tension applied to a metal strip passing through a process line by using at least three bridle rolls adjacent to each other.
First and second tension detecting steps for detecting actual tension values, which are values of tension applied to the metal strip, between two bridle rolls adjacent to each other among the three bridle rolls. When,
In accordance with a tension deviation that is a deviation between a tension actual value detected in the first tension detecting step and a preset tension setting value, the actual tension value detected in the first tension detecting step is A speed change value derivation step for deriving a speed change value with respect to a preset plate speed reference value so as to be equal to the tension setting value;
A speed command value deriving step of deriving a speed command value obtained by changing the plate passing speed reference value by the speed change value;
A tension fluctuation deriving step for deriving a time differential value of the actual tension value, which is a value obtained by temporally differentiating the actual tension value detected by the second tension detecting step;
A speed command correction value deriving step for deriving a correction value for the speed command value in accordance with the time differential value of the actual tension derived by the tension variation deriving step;
A correction step of correcting the speed command value derived by the speed command value deriving step using the correction value derived by the speed command correction value deriving step;
The speed command value obtained by correcting the rotational speed of the motor that drives the relatively upstream bridle roll among the two bridle rolls adjacent to each other with the first tension detection step interposed therebetween, is corrected by the correction step. And a speed control step for controlling based on
The speed command correction value deriving step derives a correction value for the speed command value so as to reduce the rotational speed of the bridle roll when the sign of the time differential value of the actual tension is positive. A tension control method, comprising: deriving a correction value for the speed command value so as to increase the rotational speed of the bridle roll when the sign of the time differential value of the actual tension is negative. The first tension detection step includes a track record of tension that is a value of a tension applied to the metal strip between two bridle rolls that are adjacent to each other on the relatively downstream side among the three bridle rolls. Detect the value,
The second tension detecting step is a result of tension that is a value of a tension applied to the metal strip between two bridle rolls adjacent to each other on the relatively upstream side among the three bridle rolls. The tension control method according to claim 6, wherein a value is detected. The first tension detecting step is a result of tension that is a value of a tension applied to the metal strip between two bridle rolls adjacent to each other on the relatively upstream side among the three bridle rolls. Detect the value,
The second tension detecting step is a result of tension that is a value of tension applied to the metal strip between two bridle rolls adjacent to each other on the relatively downstream side among the three bridle rolls. The tension control method according to claim 6, wherein a value is detected.   The speed command correction value deriving step uses a value obtained by multiplying the time differential value of the actual tension value by a coefficient corresponding to the sign of the time differential value of the actual tension value derived in the tension fluctuation deriving step. The tension control method according to any one of claims 6 to 8, wherein a correction value is derived.   In the speed command correction value deriving step, a value obtained by multiplying the time differential value of the actual tension value by a sign corresponding to the sign of the time differential value and the absolute value of the actual tension value derived in the tension fluctuation deriving step is obtained as the speed command value. The tension control method according to claim 9, wherein the tension control method is derived as a correction value for. The tension applied to the metal strip passing through the process line by using at least three bridle rolls adjacent to each other is set between the two bridle rolls adjacent to each other among the three bridle rolls. A computer program for causing a computer to perform control using actual tension values detected by the first and second tension detecting means arranged,
In accordance with a tension deviation that is a deviation between a tension actual value detected by the first tension detecting means and a preset tension setting value, the actual tension value detected by the first tension detecting means is A speed change value derivation step for deriving a speed change value with respect to a preset plate speed reference value so as to be equal to the tension setting value;
A speed command value deriving step of deriving a speed command value obtained by changing the plate passing speed reference value by the speed change value;
A tension fluctuation deriving step of deriving a time differential value of the actual tension value, which is a value obtained by time-differentiating the actual tension value detected by the second tension detecting unit;
A speed command correction value deriving step for deriving a correction value for the speed command value in accordance with the time differential value of the actual tension derived by the tension variation deriving step;
A correction step of correcting the speed command value derived by the speed command value deriving step using the correction value derived by the speed command correction value deriving step;
The rotational speed of the motor that drives the relatively upstream bridle roll among the two bridle rolls adjacent to each other with the first tension detecting means sandwiched between the speed command value corrected in the correcting step. An output step for performing processing for outputting to the speed control means for controlling
To the computer,
The speed command correction value deriving step derives a correction value for the speed command value so as to reduce the rotational speed of the bridle roll when the sign of the time differential value of the actual tension is positive. A computer program for deriving a correction value for the speed command value so as to increase the rotational speed of the bridle roll when the sign of the time differential value of the actual tension is negative.

Images