JP2839813B2 - Material tension and looper angle control device for continuous rolling mill - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device which includes a mechanical looper between stands of a continuous rolling mill and controls the tension between the stands and the looper angle to respective set values.

[0002]

2. Description of the Related Art First, the operation of a looper disposed between a continuous rolling mill and its stand will be described. FIG. 2 shows an outline of the continuous rolling mill. The material to be rolled 1 is carried in from the left in FIG. 2 and rolled by the former stand 2, passed between stands, rolled by the latter stand 3, and carried out to the right in FIG. 2.
At this time, since the material to be rolled is connected and simultaneously rolled between the former stand and the latter stand, tension is applied to the material to be rolled according to the amount of the material coming out of the former stand and the amount of being drawn into the latter stand. Since this material tension greatly affects the accuracy of product dimensions and the stability of rolling, a device 4 called a looper is installed between stands. When the looper rotates counterclockwise about the axis, the non-rolled material between the stands is pushed up to increase the tension of the material to be rolled, and when rotated in a clockwise direction, the tension of the material to be rolled decreases.

A conventional control method will be described below. In rolling when the size or temperature of the material to be rolled changes greatly, such as at the tip or tail end of the material, the material tension between the stands greatly fluctuates, and the looper tends to become unstable. For this reason, as shown in FIG. 3, a tension controller 9 for inputting a set value of the material tension and a detected value of the looper angle and calculating a looper driving torque necessary for setting the material tension to the set value, In general, control is performed using a looper height control device 10 that inputs a deviation between the set value and the detected value and calculates a correction amount of the rolling speed so that the deviation becomes zero (reference Literature: The Iron and Steel Institute of Japan, “Theory and Practice of Sheet Rolling” p.306). This control method will be described in detail with reference to FIG.

First, the tension control device 10 shown in FIG. 3 will be described. Considering the static balance between the looper angle θ [rad] and the material tension T [kgf / mm ² ], the torque applied to the looper rotation axis can be divided into the following three. (1) torque by material tension _{G T (T, θ) =} k 1 {sin (θ + θ 2) -sin (θ-θ 1)} T [N · m] ··· (1) (2) Materials weight W _S [kg] and looper weight W _L [kg] by the torque _{G W (θ) = (k} 2 W S + k 3 W L) cos (θ) [N · m] ··· (2) (3) torque due to the bending of material _{G B (θ) = k 4} (Lsin (θ) -H) cos (θ) [N · m] ··· (3) in these formulas, k ₁ to k ₄ is a positive constant, L is the distance between stands
[mm] and H are pass line heights [mm]. From these, when the looper angle is θ [rad] and the material tension is T [kgf / mm ² ],
Torque applied to the looper _{shaft, G M (T, θ)} = G T (T, θ) + G W (θ) + G becomes _{B (θ) ··· (4)} . Therefore, the detection value of the looper angle theta [rad] and the set value of the material tension by ^{To [kgf / mm 2] (} 1) Calculate the ~ (4), the torque of G _M (the To, theta) to the looper rotary shaft Is given by the looper motor, the material tension T is balanced with the set value To.

Next, the looper height control device 10 shown in FIG. 3 will be described. PID control is performed so that the deviation Δθ [rad] between the detected value θ [rad] of the looper angle and its set value θo [rad] Δθ = θo−θ (5) becomes zero, and the former stage and / or Correct the mill motor speed of the rear stand. The correction amount Δv [mm / s] of the rolling speed is calculated by the following equation. _{Δv = k 5 · d {Δθ} } / dt + k 6 · Δθ + k 7 · ∫Δθdt ··· (6) where, k ₅ to k ₇ in the case of correcting the mill motor speed of the front stand is a constant Is a positive value, and has a negative value when correcting the mill motor speed of the subsequent stand. Also, d {Δθ} / dt represents the time derivative of Δθ, and ∫Δθdt represents the time integration of Δθ.

[0006]

At the tip of the material, the looper angle θ and the tension T are both set to θo.
And smaller than To. In the case of the conventional control device, the looper angle θ is controlled by correcting the rolling speed, and the material tension T is controlled by the looper motor current, so that the looper driving torque G _M (To, θ) and the rolling speed are corrected. When the quantity Δv is calculated based on the equations (1) to (6), G _M (To,
θ) and Δv both act in an increasing direction. Increasing the looper driving torque G _M (To, θ) has the effect of increasing the looper and increasing the material tension, and increasing the correction amount Δv of the rolling speed helps the looper to rise,
It has the effect of reducing material tension. Therefore, when viewed from the material tension, the action due to G _M (To, θ) and Δv are offset, and
The time required for the material tension to reach the set value is delayed.

At the tail end of the material, the set value of the looper angle θo and the set value of the material tension To are both set in the steady state rolling to prevent the material from jumping up when the material comes out of the preceding stand. Make it smaller. Immediately after the setting value is reduced, the looper angle θ and the tension T are both larger than the respective setting values θo and To. Similarly, the looper drive torque G _M (To, θ) and the correction amount Δv of the rolling speed are defined as (1) to
(6) is calculated based on the formula, G _M (To, θ) and Δv is acting in a direction to decrease both. Looper driving torque G _M (To,
Reducing θ) has the effect of lowering the looper to reduce the material tension, and decreasing the correction amount Δv of the rolling speed helps lower the looper, but has the effect of increasing the material tension. Therefore, for material tension, G
_The effects of _M (To, θ) and Δv are canceled out, and the time required for the material tension to reach the set value also becomes longer.

In continuous rolling, the effect of the material tension between the stands greatly affects the product dimensions and the stability of rolling, so it is desirable that the material tension quickly reach the set value. However, in the case of the conventional control device, it is difficult to quickly reach the set value of the material tension due to the above-mentioned cause.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a control device for a tension looper angle control between stands of a continuous rolling mill, in which a material tension at a front end portion and a tail end portion quickly reaches a set value.

[0010]

SUMMARY OF THE INVENTION According to the present invention, in a continuous rolling mill, a set value of a looper angle disposed between stands and a set value of a material tension between stands are inputted, and the looper angle is maintained at the set value. A first control device that calculates a looper drive torque required for the first control device and issues a command to a looper motor current control device based on the looper drive torque, and inputs a material tension detection signal and its set value, and sets the material tension to a set value. And a second control device for calculating a rolling speed correction amount required to hold the rolling speed and for giving a command to a mill motor speed control device of a front stand and / or a rear stage stand based on the rolling speed correction amount. And a looper angle control device between stands of a continuous rolling mill.

[0011]

The operation of the present invention will be described with reference to FIG. The first control device 11 inputs the set value θo of the looper angle and the set value To of the material tension, and calculates the looper driving torque required to maintain the looper angle θ at the set value θo.
Therefore, when the current looper angle is smaller than the set value, it acts in a direction to increase the current of the looper motor.
Conversely, if the current looper angle is greater than its set value,
It acts in the direction of decreasing the current of the looper motor.

The second control unit 12 inputs a material tension detection signal T and its set value To, and calculates a rolling speed correction amount required to maintain the material tension T at the set value To. Therefore, when the current material tension is smaller than the set value, the rolling speed is corrected to act in a direction of pulling the material between the stands. Conversely, if the current tension is greater than its set value, it acts to loosen the material between the stands.

[0013] Increasing the current of the looper motor involves:
It has the effect of raising the looper and pulling the material between the stands. Modifying the speed of the mill motor to pull the material between the stands has the effect of increasing the tension and lowering the looper. At the tip of the material,
The looper angle θ and the tension T are both set values θo and To respectively.
Is smaller than. At this time, the control device of the present invention increases the looper driving torque by increasing the looper current, and pulls the material between the stands by correcting the mill motor speed of the front stand and / or the rear stand, thereby increasing the material tension. Acts in the direction of increasing. This means that when viewed from the looper, the action of the looper current and the action of the mill motor are canceled out, and the speed of the rise is slowed down. There is.

At the tail end of the material, the set value of the looper angle θo and the set value of the material tension To are both set at a steady state in order to prevent the material from jumping up when the material comes off from the preceding stand. Make it smaller. Immediately after the setting value is reduced, the looper angle θ and the tension T are both larger than the respective setting values θo and To. At this time, the control device of the present invention reduces the looper driving torque by reducing the looper current, and relaxes the material between the stands by correcting the mill motor speed of the front stand and / or the rear stand, thereby reducing the material tension. Acts in the direction of decreasing. This means that the action of the looper current and the action of the mill motor are offset from the viewpoint of the looper, and that the speed of the descent is slowed down. There is.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first control device 11 shown in FIG. 1 calculates a looper angle target value θo and a material tension target value To into a formula (4).
_{(7) G M (To,} θo) = G T (To, θo) + G W (θo) + G B (θo) ··· (7) to calculate the torque G _M Rupamota is the looper rotary shaft ( T
o, θo) [N · m] is given to the looper motor current controller 8. At this time, when the looper angle θ and the material tension T coincide with the set values θo and To, respectively, the torque given by the looper motor to the looper rotating shaft and the torque given by the material tension and the looper own weight to the looper rotating shaft are balanced. Further, when the material tension T matches the set value To and the looper angle θ is larger than the set value θo, the torque applied to the looper rotating shaft by the material tension becomes larger than the torque of the equation (7). The torque acts downward on the looper rotation axis, and the looper angle θ moves toward its set value θo. Similarly, when the material tension T matches the set value To and the looper angle θ is smaller than the set value θo, the looper angle θ also approaches the set value θo. In any case, the material tension T
Is equal to the set value To, the looper angle θ converges to the set value θo.

The second controller 12 shown in FIG. 1 calculates a deviation ΔT [kgf / m ² between the detected value T of the material tension and the set value To [kgf / mm ² ].
m ² ] ΔT = To−T (8) PID control is performed so that the mill motor speed of the front and / or rear stands is corrected. The correction amount Δv ₁ [mm / s] of the rolling speed is calculated by the following equation. _{Δv 1 = k 8 · d {} ΔT} / dt + k 9 · ΔT + k 10 · ∫ΔTdt ··· (9) where, k ₈ to k ₁₀ is when modifying the mill motor speed of the front stand is a constant Has a negative value, and has a positive value when correcting the rolling speed of the subsequent stand. Also, d
{ΔT} / dt represents the time derivative of ΔT, and ∫ΔTdt represents the time integral of ΔT. When the material tension T is smaller than the set value To, the controller 12 takes a positive value for ΔT in Expression (8).
If you decide to modify the front stand mill motor speed,
Since Δv _{1 in} equation (9) has a negative value, the material between the stands is pulled and the tension T increases. Similarly, when the material tension T is larger than the set value To, the tension T decreases. Furthermore, since Δv ₁ is calculated by integrating the error ΔT between the material tension T and the set value To, if the error ΔT is not zero, Δv ₁ gradually increases and the error ΔT always becomes zero. . From the above, the material tension T always converges to the set value To, and at that time, the looper angle θ becomes the set value θo.
Converges to

FIG. 4 shows the result of comparison between the conventional control device and the control device of the present invention with respect to the material tension. As is apparent from the figure, when the control device of the present invention is used, the time required for the material tension to reach the set value is reduced to about 1/3 or less as compared with the conventional control device.

[0018]

As described above, according to the present invention, the time required for the material tension to reach the set value is significantly reduced as compared with the conventional control device, so that the product dimensional accuracy at the tip end and the tail end is improved. Has the effect of doing In the case of continuous rolling, if the tension is low, the material may meander and the operation may be stopped. In the case of the control device of the present invention, the time of low tension can be shortened, so that there is an effect of reducing the risk of stopping the operation and improving the stability of the operation.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of one embodiment of the present invention.

FIG. 2 is a schematic side view for explaining an outline of a continuous rolling mill and an operation of a looper.

FIG. 3 is a block diagram illustrating a configuration of a conventional control device.

FIG. 4 is a graph showing simulation results comparing the operation of a conventional control device with the control device of the present invention.

[Explanation of symbols]

1: Material to be rolled 2: Pre-stage stand 3: Post-stage stand 4: Looper device 5: Mill motor 6: Looper motor 7: Mill motor speed control device 8: Looper motor current control device 9: Tension control device 10: Looper height control device 11: No. 1st control device 12: second
Control unit

Claims (1)

(57) [Claims] In a continuous rolling mill, a set value of a looper angle disposed between stands and a set value of a material tension between stands are input, and a looper driving torque required to maintain the looper angle at the set value is determined. A first control device that calculates and issues a command to the looper motor current control device based on the looper driving torque, and is necessary for inputting a material tension detection signal and its set value and holding the material tension at the set value. A continuous rolling mill, which calculates a rolling speed correction amount, and has a second control device that gives a command to a mill motor speed control device of a first stand and / or a second stage stand based on the rolling speed correction amount. Material tension and looper angle control device.