JPH0576370B2 - - Google Patents

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to a looper control device for a continuous rolling mill, and more particularly to a continuous rolling mill having at least two rolling stands and a looper disposed between the rolling stands. A first control system that calculates a current reference for a looper motor that drives the looper from an inter-stand tension reference of a material to be rolled by the machine and a looper angle, and controls the current of the looper motor in accordance with this current reference. and calculate a speed correction amount for the main motor that drives the rolling stand based on the deviation between the looper angle target value and the looper angle detected value, and adjust the main motor to:
The present invention relates to a looper control device for a continuous rolling mill, including a second control system that controls the speed in accordance with a corrected speed reference in which the speed reference is corrected by the speed correction amount.

[Technical background of the invention and its problems]

A configuration in which at least two sets of rolling stands are provided and a looper is disposed between the rolling stands is as shown in FIG. The material to be rolled 3 is sequentially rolled by two rolling stands 1 and 2 arranged in series, and the inter-stand tension of the material to be rolled 3 is controlled by a looper 4 arranged between both stands via a looper motor 5. Controlled to target value. Even in the case of continuous rolling using a rolling mill with three or more stands, the configuration between each rolling stand is as shown in FIG. 4.

When passing a material to be rolled in the apparatus shown in FIG. 4, there is a method in which the looper 4 is placed on standby at the lower limit position, and the looper 4 is raised after the tip of the material to be rolled 3 is caught in the downstream rolling stand 2. It is used. Generally, during sheet passing, the tension between the stands of the material to be rolled 3 becomes excessive or an excessive loop occurs between the stands due to errors in the settings of the rolling mill or fluctuations in the tip size or temperature of the material to be rolled 3. or In particular, excessive loops cause misrolls, so this must be quickly absorbed and controlled to a predetermined looper height.

Conventionally, looper control cannot handle excessive loops that occur during sheet threading, and the operator has to manually intervene to speed up the main engine.

FIG. 5 shows a conventional looper control device. The current of the looper motor 5 that drives the looper 4 is controlled by a current control device 6, and the speed of the main motor 8 that drives the upstream rolling stand 1 is controlled by a speed control device 9. The tension between the stands of the material to be rolled 3 can be maintained at the target value by adjusting the current reference I _ref to the current control device 6 using the current reference calculation device 10 according to the looper angle detection value θ and the tension reference t _ref . can. The looper angle detection value θ is obtained by the looper angle detector 7. The current reference I _ref calculated by the current reference calculation device 10 is expressed by equation (1).

I _ref = F ₃ (θ)・A/t _ref +F ₄ (θ) ・W _S +F ₅ (θ)・W _R +I _ACC +I _LOSS ...(1) However, I _ref : Looper motor current reference [A] A : Cross-sectional area of rolled material [mm ² ] t _ref : Standard tension between stands [Kg/mm ² ] W _S : Weight of rolled material between stands [Kg] W _R : Weight of looper [Kg] I _ACC : Looper acceleration Current [A] I _LOSS : Looper motor loss current [A] θ: Looper angle detection value [deg] F ₃ (θ): Conversion coefficient [A/Kg・mm] F ₄ (θ): 〃 [A/Kg] F ₅ (θ): Conversion coefficient [A/Kg] In equation (1), the looper acceleration current I _ACC provides the acceleration current necessary for raising the looper during sheet passing. Further, the conversion coefficients F ₃ (θ), F ₄ (θ), and F ₅ (θ) are each a function of the looper angle.

The height of the looper 4 is maintained at a target value by adjusting the rotational speed of the main motor 8 of the rolling stand 1 using a looper height control device 12 and correcting the loop amount of the rolled material between the stands. Main motor motor 8
The correction amount ΔN _ref for the speed reference N _ref is calculated by the looper height control device 12 according to equation (2), for example.

ΔN _ref = 1 + T ₂ · S / T ₁ · S (θ _ref - θ) ...(2) However, ΔN _ref : Speed correction amount [rpm] T ₁ : Integral time constant [sec] T ₂ : Advance compensation time constant [ sec] θ: Looper angle detection value [deg] θ _ref : Looper angle target value [deg] S: Laplace operator And the calculation of (θ _ref - θ) in this is performed by the subtractor 11
It will be held in The main motor motor speed correction amount ΔN _ref calculated by the looper height control device 12 is added to the main motor motor speed reference N _ref of the rolling stand 1 by an adder 13 to become a corrected speed reference N _S , and the speed control device 9
given to.

FIG. 6 schematically shows the movement of the looper during sheet passing in conventional looper control. FIG. 6a shows the on/off state of a load relay (not shown) of the upstream rolling stand 1, which is turned on while the rolling stand 1 is rolling a material to be rolled. Figure b shows the on/off state of a similar load relay in the downstream rolling stand 2.

At time _t1 , the material to be rolled 3 is bitten into the rolling stand 2, and at time _t2 , the looper 4 starts to rise. At time _t3 , the looper 4 has reached the target angle as shown in Figure c, but at this point the required tension between the stands has not yet been generated, indicating that an excessive loop has occurred between the stands. It shows. At time _t3 , the looper height control device 12 substantially starts operating and outputs an output to decelerate the rolling stand 1 (see e in the same figure), but the excessive loop between the stands cannot be absorbed. The looper angle has further increased. At time _t4 , when the looper 4 hits the rolled material 3 and tension between the stands is generated (see d in the figure), the looper 4 starts to descend. The subsequent looper angle and inter-stand tension are oscillatory and cause deterioration of product width accuracy. In this way, in the conventional looper control device, the response of the looper height control system is poor and the rolling stand 1 cannot be quickly decelerated even though it detects that the looper has reached the target angle or more, so the time t It took a long time for the looper angle to return to the target angle from ₃ , and there was a great risk of misrolling due to excessive looping of the material to be rolled. In such a case, the operator has to deal with the problem manually, which places a heavy burden on the operator, and especially in the case of a downstream stand for finishing, manual intervention may not be in time and roll errors may occur. If the time from time _t3 until the looper angle returns to the target angle can be shortened, the risk of misrolling will be reduced, the looper angle and the tension between the stands can be quickly stabilized, and stable rolling can be achieved. . However, the upper limit of the response of the looper height control system is determined by the response of the speed control device 9 for the main motor and the resonance frequency of the looper system, so it is impossible to absorb the loop during threading with the looper height control system. It was difficult.

[Purpose of the invention]

The present invention eliminates the risk of misrolling by automatically and quickly absorbing excessive loops that occur when rolling material is threaded, thereby improving product yield and productivity. The purpose of this invention is to provide a looper control device for a continuous rolling mill.

[Summary of the invention]

In order to achieve the above object, the present invention provides that the looper angle detection value is fixed to the looper for a certain period of time from the time when the material to be rolled is caught in a rolling stand located downstream of the looper and the looper starts to rise. a first calculation means that outputs the deviation only when the angle target value is exceeded; a second calculation means that integrates the deviation obtained by the first calculation means; The present invention is characterized in that a third calculation means is provided for applying a second correction in the direction of decreasing the looper to the speed reference of the main motor for driving the rolling stand in accordance with the integral value thus obtained.

[Embodiments of the invention]

The present invention will be described in detail below based on an embodiment shown in FIG. To summarize, the looper angle deviation Δθ, which is the difference between the looper angle target value θ _ref and the looper angle detected value θ, is input to the control device 20 provided according to the present invention, and the material to be rolled is placed in the downstream rolling stand 2.
The looper angle deviation Δθ is integrated only when the looper angle deviation Δθ is negative during the ON period of the switch 21 that is turned on for a certain period of time from the looper rising timing when the looper is caught in the looper, and the rolling stand 1 is adjusted according to the integrated value. The output ΔN _S,ref for decelerating the speed in steps is algebraically added to ΔN _ref by the main motor motor speed correction amount which is the output of the looper height control device 12, and the input of the speed control device 9 is decelerated and corrected. The speed of the rolling stand 1 is corrected to quickly absorb the loop.

Now, the looper angle deviation Δθ which is the output of the subtractor 11 is expressed by equation (3).

Δθ=θ _ref −θ ……(3) where Δθ: looper angle deviation [deg] θ: looper angle detection value [deg] θ _ref : looper angle target value [deg] If the looper angle θ becomes larger than the target angle θ _ref ,
When the looper angle deviation Δθ becomes negative, a loop has occurred in the material to be rolled between the stands.

This looper angle deviation Δθ is input to the arithmetic unit 22, from which the deviation Δθ' expressed by equation (4) is output.

When θ≧θ _ref , Δθ′ = −Δθ (4a) When θ<θ _ref, Δθ′ = 0 (4b) The deviation Δθ′ is input to the integrator 23, and the integral value shown by equation (5) is _LX is output.

L _X =∫ ^T ₀ ⁰ Δθ′dt (5) where L _X : Integral value of looper angle deviation [deg·sec] Integration is performed only during the period T ₀ when the switch 21 is on. This integrator 23 holds the deceleration amount of the rolling stand 1 calculated by a calculation device 24, which will be described next, and also functions to prevent malfunctions due to sampling noise included in the detected looper angle value θ. The arithmetic unit 24 outputs a deceleration amount ΔN _S,ref that changes in a stepwise manner as shown in FIG. 2 in accordance with the output integral value L _X of the integrator 23 as a speed correction amount. In FIG. 2, the speed correction amount ΔN _S1 per step and the dead band _ΔL The speed correction amount ΔN _S,ref obtained in this way is sent to the looper height control device 12 by the adder 25.
is algebraically added to the output ΔN _ref of , and the total correction amount ΔN _T,ref shown by equation (6) is output.

Then, N _T,ref = ΔN _ref + ΔN _S,ref …(6) Furthermore, this total correction amount ΔN _T,ref is calculated by adder 1
3, is added to the speed reference _Nref , and becomes the input to the speed control device 9. The speed control device 9 decelerates the main motor 8 by ΔN _S,ref . By the above-described operation, the excessive loop occurring between the stands can be quickly reduced and the looper angle can be returned to a predetermined value.

FIG. 3 schematically shows the operation of the apparatus shown in FIG. At time _t1 , the material to be rolled 3 is caught in the rolling stand 2, and at time _t2 , the looper 4 starts to rise and the switch 21 is turned on. When the looper height becomes higher than the target value at time _t3 , the integration device 23 performs integration based on the output Δθ' of the arithmetic device 22, and the time
At _t4 , the output _LX of the integrator 23 becomes larger than the correction amount dead band _ΔLX , and the arithmetic unit 24 outputs the corrected deceleration amount ΔN _S,ref as shown in equation (7).

ΔN _S,ref =ΔN _S1 (7) Further, at time _t5 , a second deceleration is performed, and the deceleration amount ΔN _S,ref is output as shown in equation (8).

ΔN _S,ref =2·ΔN _S1 (8) In this way, the looper angle rapidly returns to the target angle.

The present invention is not limited to the one embodiment described above, and can also be realized by a computer within the scope of the gist of the present invention. Furthermore, although the embodiment shown in FIG. 1 shows the case of a continuous detection system, in the case of a sampling detection system, the integrator 23 and the arithmetic unit 2
Instead of 4, the deceleration amount ΔN _S1 is output every time it is detected that the looper angle deviation Δθ' of several scans is continuously equal to or higher than the target angle, that is, in accordance with the actual deviation integral value. It can be realized.

In the embodiment detailed above, a case has been described in which a reduction in speed is applied to the main motor that drives the rolling stand on the upstream side of the looper in order to reduce the excessive looper. This can also be achieved by modifying the acceleration of the main motor. Furthermore, it is clear that deceleration corrections to the upstream main engine motor and acceleration corrections to the downstream main engine motor can be applied simultaneously.

〔Effect of the invention〕

According to the present invention as described above, it is possible to quickly eliminate excessive loops during rolling material passing, which were difficult to control with conventional looper control devices, thereby improving product yield and productivity. It is possible to provide a looper control device for a continuous rolling mill that can be improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a looper control device for a continuous rolling mill according to the present invention, and FIG.
A characteristic diagram showing the characteristics of the arithmetic device 24 in the figure,
FIG. 3 is a time chart showing one operation mode of the apparatus of the same embodiment, FIG. 4 is a layout diagram of a known continuous rolling mill to which the present invention is applied, and FIG. 5 is a block diagram of a conventional looper control device. FIG. 6 is a time chart explaining the movement of the looper in conventional looper control. 1, 2... Rolling stand, 3... Material to be rolled, 4
... Looper, 5 ... Looper motor, 6 ... Current control device, 7 ... Looper angle detector, 8 ... Main motor motor, 9 ... Speed control device, 10 ... Current reference calculation device, 11 ... Subtraction device, 12... looper height control device, 13... adder, 21... switch, 22
... Arithmetic device, 23... Integrator, 24... Arithmetic device, 25... Adder.

Claims (1)

[Scope of Claims] 1. The looper is calculated based on the inter-stand tension reference and the looper angle of a rolled material to be rolled in a continuous rolling mill having at least two rolling stands and a looper disposed between the rolling stands. a first control system that calculates a current reference for the looper motor to be driven and controls the current of the looper motor according to the current reference; and a first control system that controls the rolling stand based on the deviation between the looper angle target value and the looper angle detected value. Calculate the speed correction amount of the main motor to be driven, and adjust the main motor to:
A looper control device for a continuous rolling mill, comprising a second control system that controls the speed in accordance with a corrected speed reference in which the speed reference is corrected by the speed correction amount, wherein the material to be rolled is located downstream of the looper. a first calculating means that outputs a deviation only when the detected looper angle value exceeds the target looper angle value for a certain period of time from the time when the looper starts to rise after being caught in a rolling stand; a second calculation means for integrating the deviation obtained by the first calculation means; and a speed reference of the main motor for driving the rolling stand according to the integral value obtained by the second calculation means. A looper control device for a continuous rolling mill, characterized in that a third calculating means applies a second correction in a direction of decreasing the looper. 2. The looper of a continuous rolling mill according to claim 1, wherein the second correction is applied in a deceleration direction with respect to a speed reference of a main motor that drives a rolling stand on the upstream side of the looper. Control device. 3. The looper of a continuous rolling mill according to claim 1, wherein the second correction is applied in the acceleration direction with respect to a speed reference of a main motor that drives a rolling stand downstream of the looper. Control device. 4 The second correction is applied in the deceleration direction with respect to the speed reference of the main motor motor that drives the rolling stand on the upstream side of the looper, and the speed reference of the main motor motor that drives the rolling stand on the downstream side of the looper is applied in the direction of deceleration. A looper control device for a continuous rolling mill according to claim 1, characterized in that the looper control device is applied in a direction. 5. A looper control device for a continuous rolling mill according to claim 1, wherein said third calculation means outputs a speed correction amount that changes in steps in accordance with said integral value.