JPH11123429A - Control method and device for tension of beltlike material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a tension fluctuation from being generated more than necessary at the time of acceleration and deceleration. SOLUTION: In this control method for the tension of the belt-like material, from nondrive rolls R1 to R6 in an area aiming at a tension control and the moment of inertia of a threading material 10, a tension fluctuation quantity ΔTt generating in the position of a tension gage roll R5 at the time of the acceleration and the deceleration of a line, is calculated. By correcting tension detected value Tf or tension set value Tref according to this tension fluctuation quantity ΔTf, a feedback control is performed. In addition, drive rolls D1 to D3 in each section are inserted as necessary aiming at mainly slip prevention, etc., however, since they are driven at a target speed, they do not contribute to the tension fluctuation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for controlling the tension of a strip which performs a tension feedback control based on a tension value detected by a tension detecting means. A tension meter is installed in the equipment that manufactures or processes the material, and the tension of the material to be processed is controlled at a constant level. The present invention relates to a method and an apparatus for controlling a tension of a band-shaped material without any trouble.

[0002]

2. Description of the Related Art First, a tension control in a continuous processing line will be described with reference to an equipment layout shown in FIG. 7A, taking a continuous rolling line for continuously rolling a strip 10 by a rolling stand 20 as an example. In such a continuous processing line, bridle rolls B1 and B2 are inserted everywhere (two places in FIG. 7), and the section between the bridle rolls B1 and B2 is usually subjected to independent tension control as one section. . This section includes bridle rolls at both ends, so that the front and rear sections share the border bridle roll.

Usually, most of the drive rolls D1 to D3 in this section, including the front and rear bridle rolls, are responsible only for speed control, and have a tension control function at one location (usually the front or rear bridle roll). doing. For example, the entrance bridle roll B1 and the driving rolls D1 to D3 are driven only by speed control, and only the exit bridle roll B2 has a function as a tension control roll. In the figure, R1 to R6 are non-driving rolls.
5 is provided with a tensiometer and is used as a tensiometer roll.

When the line is accelerated, the driving rolls B1, B2, D1 to D3
Is accelerated according to the speed control. However, since the strip in the section and the non-driving rolls R1 to R6 have inertia, an inertial force in the compression direction is applied to the strip on the upstream side as shown in FIG. The tension decreases, and on the downstream side, the inertia force in the tensile direction is applied, and the tension increases.

[0005] Here, assuming that the total amount of tension fluctuation based on the inertial force in the section due to acceleration is ΔT as shown in FIG. 7 (B), -ΔT / 2 on the entry side of the section and + ΔT on the exit side. / 2 tension fluctuations usually occur. When only the speed control is performed without adding any tension control, FIG.
As shown in (B), the intermediate value (so-called median value) between the entrance tension and the exit tension matches the tension in the steady state. The same applies to the case where the line is decelerated, except that the sign of the tension fluctuation is reversed.

FIG. 8 shows an example of a conventional tension fluctuation at the time of acceleration / deceleration.

[0007] If such a tension fluctuation is large, a slip occurs in the section or the tension fluctuation propagates out of the section, causing troubles such as meandering and breakage in a continuous heat treatment furnace, and the like, in passing through the preceding and following processes. Is generated.

For this reason, various methods have been proposed for suppressing the above-mentioned fluctuations in tension during acceleration / deceleration. The number of drive rolls can be increased, or a dancer roll, a damper roll, or the like can be provided in a section or before or after a section. Install it,
A proposal to absorb the tension fluctuation (for example,
237018).

[0009]

However, these countermeasures are generally expensive, and a section for passing a plate near room temperature, such as an inlet / outlet processing unit of a main unit, has a relatively large tension. Ranges are acceptable. Therefore, the steady-state tension ± ΔT
If the line design allows up to / 2, there should be no need to take special measures against these tension fluctuations.

However, in a continuous processing line, it is usual that the tension must be controlled within a certain range at least in a steady state. Therefore, the tension in the steady state is monitored while monitoring the tension with a tension meter roll or the like. In many cases, management and control are performed so that the tension target value is obtained. However, since the position of the tension meter is not usually at the position where the tension fluctuation is zero in the section (the position where the tension indicates the median value), the acceleration / deceleration of the tension meter as shown in FIG. That is, the value obtained by adding the fluctuation of the tension associated with is monitored.

If control is applied based on this monitor value, the median value should be set as the tension target value originally.
As shown in FIG. 7 (C), since the deviation from the median value is caused by the previously added tension fluctuation, there is a risk that any of the sections deviates from the previously assumed tension target value ± T / 2. . Therefore, unless the tension fluctuation value is designed to be considerably small, stable operation cannot be achieved.

Of course, if the tension meter is located exactly at the position where the tension fluctuation is zero in the section (the position where the tension indicates the median value), such a problem does not occur. It is difficult to install a tensiometer at a convenient location.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and has as its object to maintain the tension median value of the section so as to prevent unnecessary tension fluctuation from occurring.

[0014]

SUMMARY OF THE INVENTION The present invention relates to a method for controlling the tension of a strip which performs tension feedback control based on the tension value detected by the tension detecting means. This problem has been solved by calculating the amount of tension fluctuation during acceleration / deceleration to be performed and correcting the detected tension value or tension set value based on the amount of tension fluctuation and performing control.

[0015] Further, a tension detecting means provided in an area to be subjected to the tension control, a tension applying means for applying a tension to the belt-like material, and a detection value by the tension detecting means are inputted, and the detected value is inputted. And a control means for controlling the tension applying means based on a tension target value, wherein an acceleration / deceleration generated at a detection position of the tension detection means by an acceleration / deceleration rate and an inertia moment in the area. Means for calculating the amount of tension fluctuation at the time, and means for correcting the tension value detected by the tension detection means or the tension target value based on the amount of tension fluctuation and inputting the corrected value to the control means. And the above-mentioned problem has been solved.

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings.

In the first embodiment of the present invention, the amount of tension fluctuation occurring at the point where the tension meter is installed during acceleration / deceleration is calculated from the acceleration / deceleration rate of the section, the moment of inertia of the roll and the processing material, and the value is calculated. Is compared with the target tension value by subtracting the output value of the tension meter from the output value of the tension meter, and is controlled so as to match.

First, the basics of the calculation of the amount of fluctuation in tension generated during line acceleration / deceleration will be described.

The inertia moment of the non-driven roll is represented by GDR ²
[Kg · m ² ], and the acceleration / deceleration rate of the non-driving roll is dN /
Assuming that dt [rpm / sec], the torque τr required to accelerate and decelerate the non-driven roll is expressed by the following equation.

[0020] ^{τr = GDr 2/375 × (} dN / dt) ... (1)

Therefore, if the roll diameter of the roll for which the tension control of the section is to be performed is D [m], the tension change amount ΔTr required to accelerate and decelerate the non-driven roll is expressed by the following equation.

ΔTr = τr / (D / 2) (2)

The moment of inertia GDs ² [k
g / m ² ] is represented by the following equation, where ρ [kg / m ³ ], the cross-sectional area is A [mm ² ], and the length is L [m].

GDs ² = 10 ⁻⁶ · ρ · A · L · D ² (3)

Therefore, the torque τs required for accelerating and decelerating the strip is represented by the following equation.

[0026] ^{τs = (GDs 2/375)} × (dN / dt) ... (4)

Using this τs, the amount of change in tension ΔTs required to accelerate and decelerate the strip is expressed by the following equation.

ΔTs = τs / (D / 2) (5)

Accordingly, the tension change amount ΔT finally required at the time of line acceleration / deceleration is expressed by the following equation as the sum of these.

ΔT = ΣΔTr + ΣΔTs (6)

Therefore, the tension fluctuation distribution during acceleration when the tension control is not performed is as shown in FIG. 1 in detail, and more specifically as shown in FIG. Where S
1 to S10 are tensions between the rolls from the entrance bridle roll B1 to the exit bridle roll B2.

The drive rolls D1 to D1 in each section
D3 is inserted as needed mainly for the purpose of slip prevention or the like, but does not contribute to tension fluctuation because it is driven at the target speed.

Therefore, the tension variation ΔT ′ applied to the most downstream roll entrance of the section is expressed by the following equation.

ΔT ′ = ΔT / 2 (7)

Now, if the sum of the respective tension fluctuations from the most downstream roll to the tension meter roll is represented by adding “'”, the total tension fluctuation ΔT ″ from the most downstream roll to the tension meter roll is given by the following equation. Is represented by

ΔT ″ = ΣΔTr ′ + ΣΔTs ′ (8)

Accordingly, the calculated value of the variation in tension ΔTt of the tension meter section
Is represented by the following equation.

ΔTt = ΔT′−ΔT ″ (9)

Accordingly, in the first embodiment, the tension value Tfb to be fed back to the tension control is represented by the following equation, where the detected tension value is Tf.

Tfb = Tf−ΔTt (10)

Thus, for example, when the tension fluctuation that should be generated during acceleration is +50 kg during acceleration, conventionally, it was controlled so as to match the target value. Although the tension was reduced, in the first embodiment, the amount was subtracted from the detected tension value. Therefore, even if the detected value was higher than the target value by 50 kg, the control did not work, and the target value was calculated by the average value. Be able to maintain.

FIG. 3 shows a control block for implementing the present embodiment. In the figure, 10 is a strip, 20 is a rolling stand, B1 and B2 are bridle rolls, D1 to D1.
D3 is a drive roll, R1 to R6 are non-drive rolls including a tension meter roll R5, M is a motor for driving each drive roll, and ACR is an automatic current controller for controlling the current flowing through each motor M. (Automatic Current Regulator
), ASR is an automatic speed controller (Automatic Speed Regulator) for giving a command to each ACR, 22 is a tension meter attached to the tension meter roll R5, 30 is a tension fluctuation calculator 32 and control means according to the present invention. This is a tension control device including a PI controller 50 that is a tension controller.

The tension fluctuation calculating section 32 calculates dV / dt obtained by differentiating a line speed command V given from the outside, a total strip inertia moment in a section calculated from a strip sectional area A also given from the outside, and a tension meter roll R5. To the outlet bridle roll B2, the multipliers 34a to 34h for respectively multiplying the strip inertia moment between the rolls R1 to R6, and the adder (SU) for adding the calculation results of the multipliers 34a to 34h.
M) 36 and the moment of inertia of the tension meter roll R5 is 1 /
2; an adder (SUM) 40 for adding the outputs of the multipliers 34b, 38, and 34g;
6, a multiplier 42 for multiplying the output of C.6 by 1/2.
Subtracter 44 for subtracting the output of the adder 40 from the output of
The tension control device 30 includes a subtractor 52 that subtracts a tension variation calculation value ΔTt output from a subtractor 44 from a tension detection value Tf output from the tension meter 22, and a tension setting value Tref given from the outside. A subtractor 54 for subtracting the tension feedback value Tfb from the output of the subtractor 46 and inputting the result to the PI controller 50 is provided.

In the first embodiment, the following relationship is established.

ΣΔTr = ΔTr (R1) + ΔTr (R2) + ΔTr (R3) + ΔTr (R4) + ΔTr (R5) + ΔTr (R6) (11) ΣΔTs = ΔTs (S1) + ΔTs (S2) + ΔTs (3) + ΔTs (3) . + ΔTs (S10) (12) ΣΔTr ′ = ΔTr (R5) / 2 + ΔTr (R6) (13) ΣΔTs ′ = ΔTs (S9) + ΔTs (S10) (14)

The specific calculation of the amount of change in tension in this embodiment is performed as follows.

Now, the moment of inertia GDR ² of a non-driven roll having a roll diameter D of 500 mm is 127.0 kg / m.
² , the moment of inertia GDs of the strip per 1 m length
² , 0.785 kg / m ² / m, strip thickness 0.4 mm, width 1000 mm, roll diameter for pulling the strip 500 mm, acceleration / deceleration rate 50 mpm /
In this embodiment, as shown in the following formula, a tension fluctuation of 66.2 kg occurs between the bridle rolls B1 and B2 during acceleration and deceleration in the present embodiment.

ΔT = ΣΔTr + ΣΔTs = 10.8 × 6 + 1.4 (21 m) = 66.2 (15)

Then, at each bridle roll, as shown by the following equation, a tension fluctuation of -33.1 kg on the upstream side and 33.1 kg on the downstream side occur.

ΔT ′ = ΔT / 2 = 33.1 (16)

Further, at the tension meter roll R5, as shown in the following equation, from the bridle roll B2 on the downstream side.
The tension value is 33 kg lower.

ΔT ″ = ΣΔTr ′ + ΣΔTs ′ = 10.8 × 1.5 + 0.13 (2m) = 16.33 (17)

Here, the reason why the number of rolls is set to 1.5 is as follows.
This is because the tensiometer detects the composite value of the longitudinal tension of its own roll, and needs to calculate the value of the intermediate portion of the roll.

At the time of actual acceleration, the tension fluctuation value ΔTt in the tension meter section is 16.77 kg as shown in the following equation.

ΔTt = ΔT′−ΔT ″ = 33.1-16.33 = 16.77 (18)

Therefore, in the present embodiment, 16.77 from the tension detection signal Tf from the tension meter 22 as shown in the following equation.
kg was subtracted to obtain a tension feedback signal Tfb.

Tfb = Tf−ΔTt = Tf−16.77 (19)

As a result, during conventional acceleration, as shown in FIG. 8, the average tension value in the section was always 16.77 kg lower than the target value, causing meandering and slippage. According to FIG. 4, as shown in FIG. 4, the actual tension (average value within the section) can be made to match the set value irrespective of the variation in the detected tension value, and excellent tension control can be performed.

Next, a value obtained by adding the tension fluctuation amount ΔTt calculated in the same manner as in the first embodiment to the tension set value Tref as a tension target value Tset is compared with the detected value Tf of the tension meter 22 so that they match. In the second aspect of the present invention,
An embodiment will be described in detail.

In the second embodiment, the tension variation calculation value ΔTt calculated by the equation (9) in the same manner as in the first embodiment is added to the original tension set value Tref as shown in the following equation. The tension target value is Tset.

Tset = Tref + ΔTt (20)

Therefore, for example, during acceleration, if the tension fluctuation to be originally generated is +50 kg, conventionally it was controlled so as to match the target value. According to the present embodiment, the tension setting after correction is increased by +50 k
Since the control is performed with the target value of g, even if the detected value is 50 kg higher than the original target value, the control does not move and the target value can be maintained at the average value.

As shown in FIG. 5, the control device of the present embodiment includes a tension control device 30 similar to that of the first embodiment.
There is provided an adder 60 which adds the tension variation calculation value ΔTt of the output of the tension variation calculation unit 32 to the tension setting value Tref input from the outside to obtain a tension target value Tset. From the tension target value Tset of the output of the adder 60, The subtraction of the detected tension value Tf from the output of the tension meter 22 by the subtractor 54 is input to the PI controller 50.

In the concrete calculation of the amount of tension fluctuation in this embodiment, the tension value 16.77 kg calculated by the equation (18) as in the first embodiment is replaced by the tension set value Tref as shown in the following equation. In addition, a target tension value Tset was set.

Tset = Tref + ΔTt = Tref + 16.77 (21)

The other points are the same as those in the first embodiment, and the description is omitted.

According to the present embodiment, as shown in FIG. 6, by changing the tension set value, the actual tension can always be kept constant.

[0068]

According to the present invention, the amount of tension fluctuation at the time of acceleration / deceleration always generated in the tension meter section, which is calculated based on the moment of inertia of the roll and the processing material, is subtracted from the feedback value of the tension meter. Alternatively, since the tension is controlled by adding to the tension target value, the slip generated by the tension (average value) of the entire section generated by the tension control when the line is accelerated or decelerated decreases or increases. , Meandering, buckling, breakage, etc. could be suppressed.

[Brief description of the drawings]

FIG. 1 is a diagram showing details of a tension fluctuation distribution during acceleration when tension control is not performed.

FIG. 2 is a diagram showing further details of the tension fluctuation distribution of FIG. 1;

FIG. 3 is a block diagram illustrating a configuration of a control device according to the first embodiment of the present invention.

FIG. 4 is a diagram illustrating an example of a relationship between a line speed and a tension during acceleration / deceleration in the first embodiment.

FIG. 5 is a block diagram showing a configuration of a control device according to a second embodiment of the present invention.

FIG. 6 is a diagram illustrating an example of a relationship between a line speed and a tension at the time of acceleration / deceleration in the second embodiment.

FIG. 7 compares the equipment layout, the tension fluctuation distribution during acceleration when tension control is not performed, and the tension fluctuation distribution during acceleration when tension control is performed to explain the problems of the conventional example. Diagram showing

FIG. 8 is a diagram showing an example of a relationship between line speed and tension during acceleration / deceleration in a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Strip 20 ... Rolling stand B1, B2 ... Bridle roll D1-D3 ... Driving roll R1-R6 ... Non-driving roll R5 ... Tensiometer roll M ... Motor ACR ... Automatic current controller ASR ... Automatic speed controller 22 ... Tensiometer 30: tension controller 32: tension fluctuation calculator 50: PI controller

Claims (4)

[Claims] In a method for controlling the tension of a strip material, wherein a tension feedback control is performed based on a tension value detected by a tension detecting means, an amount of tension fluctuation during acceleration / deceleration generated by an inertia moment in a region to be tension-controlled. Calculating the tension value and correcting the detected tension value based on the tension fluctuation amount to perform control. 2. A tension control method for a belt-shaped material, wherein a tension feedback control is performed based on a tension value detected by a tension detecting means, wherein an amount of tension fluctuation during acceleration / deceleration caused by an inertia moment in a region to be tension-controlled. A tension control value is corrected based on the amount of change in the tension to perform control. 3. A tension detecting means provided in an area to be tension-controlled, a tension applying means for applying a tension to a belt-like material, and a value detected by the tension detecting means are inputted. And a control means for controlling the tension applying means on the basis of a tension target value, wherein the tension control means generates a tension at a detection position of the tension detecting means by an acceleration / deceleration rate and an inertia moment in the area. Means for calculating the amount of tension fluctuation during acceleration / deceleration; and means for correcting the tension value detected by the tension detecting means based on the amount of tension fluctuation and inputting the corrected value to the control means. Tension control device for web material. 4. A tension detecting means provided in an area to be tension-controlled, a tension applying means for applying a tension to a belt-like material, and a detection value by said tension detecting means, and the detected value is inputted. And a control means for controlling the tension applying means on the basis of a tension target value, wherein the tension control means generates a tension at a detection position of the tension detecting means by an acceleration / deceleration rate and an inertia moment in the area. A tension control device for a belt-shaped material, comprising: means for calculating a tension variation during acceleration / deceleration; and means for correcting the tension target value based on the tension variation.