JPH09276929A - Method for controlling coiler for hot rolled stock - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coiling means for hot rolled stocks by which the estimating accuracy of the tension of a material to be rolled which is situated between a finishing mill and a coiler is improved without necessitating a special device by which high cost is brought about and width reduction at the time of coiling a hot rolled stock is securely prevented. SOLUTION: This method is a control method of the coiler for hot rolled stocks for preventing the width reduction of the material to be rolled which is generated at the time of coiling the material 1 to be rolled which comes out of a hot rolling mill with the coiler 6, an estimation computing element 13 for estimating the tension generated on the material to be rolled between the finishing mill and the coiler from the number of revolution of a motor 7 for driving the coiler, armature current and counter electromotive force is provided and coiling is executed as correcting the driving torque of the coiler based on the estimated value of tension with the computing element 13, the number of revolution of the motor 7 for driving the coiler and armature current.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a "control method for a hot rolling winder" for preventing a narrow width which tends to occur when a hot rolled material is wound into a coil by a winder. It is about.

[0002]

2. Description of the Related Art Generally, in the hot rolling of a thin plate material (such as a thin steel plate), the material to be rolled out from the hot rolling machine is wound into a coil by a winding machine, and the work is completed. The outline of the process will be described with reference to FIG. 7.

In FIG. 7, the material 1 to be rolled which has been finish-rolled by the hot-rolling finishing rolling mill group 2 composed of a plurality of stands is cooled to a required temperature in the subsequent run-out table, and then the winding machine 6 is used. Is wound into a coil. The run-out table is provided with a rolled material transporting roller (table roll) 3, which is rotated at a speed higher than the exit side speed of the finish rolling mill in order to favorably transport the rolled material. are doing. At this time, the winder 6 is driven by the winder drive motor 7, and the winder drive motor 7 is controlled as follows. That is, first, the tension / current conversion device 8 calculates the current command value from the "target tension" to be generated in the material to be rolled between the finish rolling mill group 2 and the winder 6. Then, in response to this current command value, the current controller 9 sets the "tension generated in the material to be rolled between the finish rolling mill group 2 and the winder 6" to the "target tension" to control the winder drive motor. Control the torque of 7.

[0004] Usually, in such equipment, the winder 6
Is arranged at a position lower than the pass line of the material 1 to be rolled, and therefore, a pinch roll 4 for directing the traveling direction of the material 1 to be rolled to the lower side of the pass line is provided upstream of the winder 6. It is provided. In addition, the tip end of the rolled material 1 is wound by the winder 6
The winding machine 6 is provided with three or four trumpet rolls 5 for winding on the winding machine 6. While the rolled material 1 is wound around the winding machine 6 for four to five windings immediately after being wound. The rolling work is performed while the rolled material 1 is pressed against the winding machine 6 by the wrapper roll 5.

By the way, in the hot rolling equipment as described above, the rotation speed of the winder 6 is operated in association with the speed of the material-rolling roller 3 for rolling, and thus the runout table is operated. Rolled material 1 traveling above and reaching the winder 6
The speed at which the coil winds around the winder is higher than the exit speed of the finish rolling mill. Therefore, immediately after the rolled material is wound around the winder, an excessive tension is generated in the “rolled material located between the finishing rolling mill group 2 and the winding machine 6,” which causes “ "Necking" called "narrowing (local necking)"
It has been a problem that this causes the yield reduction.

Further, even during the winding of the material to be rolled, in order to improve the winding shape, the winding speed of the winding machine 6 is made higher than the exiting speed of the finish rolling machine to obtain an appropriate tension. Is applied to the "rolled material located between the finishing rolling mill group 2 and the winding machine 6." This applied tension is usually set to a level such that "steady narrow" does not occur, but when the control of the winder drive motor 7 does not work well, the applied tension is larger than the set value. Acts on the "rolled material located between the finishing rolling mill group 2 and the winding machine 6", and a narrow width corresponding to the magnitude of the "tension" occurs over the entire length of the rolled material 1. This "steady narrow width" has also been a cause of a decrease in yield.

However, some methods have been proposed so far for preventing the above-mentioned "local narrowing (necking)" and "steady narrowing" of the material to be rolled.
For example, see Japanese Unexamined Patent Publication No. Hei 6-297015, it is said that "the number of revolutions of the motor of the winder immediately after the material to be rolled is wound around the winder and the speed of the material to be rolled at the exit of the finishing mill""The tension of the material to be rolled immediately after being wound on the winder is generated" due to the difference in speed of the winder, and the speed difference between the "revolution speed of the winder" and the "speed of the rolled material at the exit of the finishing mill" The method of calculating the tension of the material to be rolled and correcting the rotation speed of the winder on the basis of the obtained tension is disclosed in the document.

However, in the above method in which the tension of the material to be rolled is first estimated from the rotational speed of the winder and the speed of the material to be rolled at the exit of the finish rolling mill, the speed of the material to be rolled is constantly maintained at the outlet of the hot finish rolling mill. It is necessary to measure accurately, but it is very difficult to measure the speed of the material to be rolled continuously and accurately under a bad environment of high temperature and high humidity such as at the exit of a hot finish rolling mill. Speedometer (laser Doppler
There is a problem in that the measured value of the speedometer of the method) has a large error, and therefore the "tension of the rolled material" estimated based on this measured value is not accurate. In addition, the cost increase due to the installation of the speedometer was also a big problem.

On the other hand, without using a speedometer,
There is also a method of obtaining the speed of the material to be rolled at the exit of the finishing rolling mill from the roll peripheral speed of the finishing rolling mill and the calculated advanced rate based on the following equation. _{V = V R (1 + f} ) [where, V: the rolled material velocity, V _R: B - Le circumferential speed, f:
Advanced calculation rate)

However, there is an unavoidable problem that the calculated advance rate has a prediction error, and the speed of the material to be rolled cannot be obtained accurately, and the tension of the material to be rolled estimated using this also has a large prediction error. It was

In view of the above, the object of the present invention is to "tension of the material to be rolled located between the finish rolling mill and the winding machine" without requiring a device which causes a particularly high cost. It is an object of the present invention to provide a hot rolling and winding means capable of improving the estimation accuracy of, and more accurately preventing a narrow width when winding a hot rolled material.

[0012]

However, in order to achieve the above-mentioned object, the inventors of the present invention have previously described "finishing rolling from the rotational speed of the motor for driving the winder and the armature current. An estimation calculator for estimating the "tension generated in the material to be rolled" between the winder and the winder is provided, and the tension controller adjusts the drive torque of the winder based on the estimated tension value by the calculator. A method of controlling the tension of the material to a target tension "has been proposed (Japanese Patent Application No. 7-227381), but after that, the further recognition of this proposed method led to the recognition as follows.

That is, in carrying out the above-mentioned proposed method, the tension is estimated by using the field magnetic flux of the winder drive motor in the "tension estimation calculator". It has been recognized that the field magnetic flux cannot be directly measured and thus a preset value must be used. In addition, in order to obtain the desired control effect by the proposed method through actual operation, “transient error until the target tension value is achieved by the tension controller device based on the estimated tension”
It has become clear that it is necessary to devise a method to suppress this because it cannot be ignored.

Therefore, as a result of further research to solve these problems, "the tension of the material to be rolled immediately after the material to be rolled is wound around the winder is the number of revolutions of the motor for driving the winder. It can be accurately estimated by considering the back electromotive force in addition to the armature current and the drive torque of the winder based on this estimated value, the rotation speed of the winder drive motor, and the armature current. By controlling it, it is possible to accurately and effectively suppress the narrow width of the material to be rolled. "

The present invention has been made on the basis of the above-mentioned findings and the like. The present invention relates to a "motor for driving a winder (winder drive motor).
Estimating the "tension generated in the material to be rolled between the finish rolling mill and the winding machine" from the rotation speed of the motor, the armature current and the back electromotive force, and the tension estimated value by the computing unit is provided. By adjusting the drive torque of the winder based on the rotation speed of the winder drive motor and the armature current, the material to be rolled out of the hot finish rolling mill is wound into a coil by the winder. The point is that it is possible to accurately prevent the narrow width of the material to be rolled that occurs when the material is taken ".

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION As described above, according to the present invention, the tension of the material to be rolled immediately after the material to be rolled is wound around the winder is counter-induced with the rotational speed of the winder drive motor and the armature current. By providing a tension estimation calculator that estimates from the electric power and the tension estimated by the above tension estimation calculator does not become a large value immediately after winding and during winding and reaches a target value The rotation speed of the winder is controlled while the drive torque of the winder is corrected based on the "difference between the estimated tension and the target tension" and the "revolution speed of the winder drive motor and armature current". The present invention relates to a technique for suppressing a narrow width by suppressing a change in tension acting on a material to be rolled, and the present invention will be described in detail below together with its operation.

First, the "tension generated in the material to be rolled between the finish rolling machine and the winding machine" after winding on the winding machine will be examined. The equation of motion of the winder after the material to be rolled is wound around the winder can be expressed by the following differential equation.

[0018]

[Equation 1] Where ω is the angular velocity of the winder, J is the inertia moment of the winder, I is the armature current of the winder drive motor, τ _{T is the} load torque due to the tension of the material to be rolled, and τ _B : Bending torque when winding the material to be rolled by the winder, τ _L : Loss torque of the winding drive system, Φ: Field magnetic flux of the winder drive motor, R: Coil radius of the winder (rolling target) It increases as the material is wound up), ζ: Constant (depending on the number of magnetic poles of the winder drive motor, the number of armature conductors and the number of parallel circuits).

At this time, the field magnetic flux Φ of the winder drive motor
Cannot be measured directly, the angular velocity ω of the winder and the back electromotive force
EMF is used to obtain indirectly from the relationship in equation (2).

[Equation 2]

When the torque expressed by the following equation (3) is defined as a state variable, the equation of motion is given by the following equation (4)
It is represented as τ _D = τ _T + τ _B + τ _L = F _T Rn + τ _B + τ _L (3) where F _T : tension generated in the material to be rolled between the finish rolling mill and the winder, n: winder drive mode -Gear ratio.

(Equation 3)

The tension generated in the material to be rolled between the finish rolling mill and the winder is caused by the difference between the winding speed on the winder and the speed at which the finish rolling mill sends it to the runout table. From the relationship between the tensile stress and strain acting on the material to be rolled between the rolling mill and the winder, the following equation is established.

[0022]

(Equation 4) Where σ: tension stress acting on the material to be rolled between the finish rolling mill and the winder, v ₇ : speed of the material to be rolled out from the finishing rolling mill to the run-out table, v _M : of the material to be rolled Winding speed around the winder, E: Young's modulus, L: Run-out table (from finish rolling mill to winder)
Length of

Here, the time response of bending torque and loss torque of the winder drive motor is sufficiently slower than the fluctuation of the tension, and the drive motor of the finish rolling mill is generally a winder drive motor.
Since the inertial moment is much larger than that of the winding machine, the change in the delivery speed from the finish rolling mill to the runout table can be ignored compared to the change in the winding speed to the winder, and therefore the following equation is established.

[0024]

(Equation 5) However, B: production plate width of rolled material, h: production plate thickness of rolled material.

By summarizing the above differential equations, this controlled object can be expressed as a matrix as follows.

(Equation 6) Here, x (t): state vector, u (t): input, y (t): output, T: transposition of vector.

In the above equation of state, an estimator for estimating the torque τ _D (for convenience, called tension torque) that cannot be directly measured is constructed as follows.

(Equation 7) In the above equation, k is the gain of the estimator, which can adjust the convergence time (T _c ) of the estimated value by this estimator, and in the embodiment of the present invention described later, “convergence time T
_c = 0.01 seconds ".

By substituting the estimated torque value calculated in this way into the above equation (3), the tension F _T of the material to be rolled can be obtained based on the following equation.

(Equation 8) As described above, the "tension generated in the material to be rolled between the finish rolling mill and the winder" can be estimated from the angular velocity of the winder drive motor and the armature current.

Next, the structure of the tension controller for correcting the drive torque of the winder on the basis of the estimated tension value and controlling the tension of the material to be rolled to the target tension will be described. When performing tension control, it is desirable to design a control system that has as little transient error as possible with the target tension. Therefore, a method of constructing an optimal servo system applying the modern control theory as a tension controller will be described.

Since the "tension generated in the material to be rolled between the finish rolling mill and the winder" can be estimated by the estimator, the output of the controlled object is the tension torque τ _D, and this torque output is the target torque. The servo mechanism that follows the above shall be designed. That is, the control target is expressed as a state vector as in the following equation, and the target tension torque τ _D ^ref is the target tension F _T ^ref.
From the above equation (3).

[Equation 9]

No matter what input τ _D ^ref is,
Although it is guaranteed that the BO mechanism can be set theoretically,
In order to simplify the description, a servo mechanism that follows a step-like target input is designed here. Here, the servo system is configured as shown in FIG.
In order to make (t) = τ _D follow the target torque τ _D ^ref without steady deviation, an integrator is arranged as a steady deviation compensator for the difference between the target torque and the output. Further, in FIG. 2, F and K are feedback matrices for making the control system asymptotically stable.

The system of FIG. 2 is expressed by the following expression in addition to the expression (10).

(Equation 10)

Here, the following equation (12) is obtained.

[Equation 11]

Next, the error system from the steady value is obtained. The following variables are prepared as the state variables of the error system.

(Equation 12)

At this time, from the equations (10) to (13), the error system can be expressed as a matrix as in equations (14) and (15).

(Equation 13)

[Equation 14]

This is the state field of equation (15) in the system of equation (14).
It can be regarded as being subjected to a debug. Therefore,
In the third-order expansion system {Equation (14)}, the weight matrix A,
B is selected and v that minimizes the evaluation function expressed by the following equation is solved for the optimum output regulator problem.

(Equation 15)

As a result, it is assumed that the optimum feedback vector can be solved as shown in equation (17).

(Equation 16)

Comparing the above equation (15) with the above equation (17), the following equation is established.

[Equation 17]

Therefore, the feedback matrices F and K in FIG.
Can be calculated based on the following equation.

(Equation 18)

The present invention will be described below with reference to examples.

EXAMPLE FIG. 1 is an explanatory diagram relating to the hot rolling equipment for steel sheets used in this example. In FIG. 1, 1 is a material to be rolled, 2 is a group of hot finish rolling mills, 3 is a roll for transporting the material to be rolled.
La (table roller), 4 is a pinch roll, 5 is a wrapper roll, 6 is a winder, 7 is a winder drive motor, 9 is a current controller, and 10 is a current measuring device. , 11 is a motor angular velocity measuring device, 12 is a motor back electromotive force measuring device, 13 is a tension estimation calculator,
Reference numeral 14 is a tension control device, and 15 is a calculator.

In the hot rolling equipment shown in FIG. 1, the material to be rolled 1 rolled by the hot rolling mill group 2 composed of a plurality of stands is cooled to a required temperature in the subsequent runout table, It is wound into a coil by the winder 6.
Here, the narrowing prevention control by the tension control according to the present invention operates from the moment the rolled material 1 is wound around the winder 6,
First, the armature current of the winder drive motor 7 and the motor angular velocity,
The back electromotive force is measured by the current measuring device 10, the angular velocity measuring device 11, and the back electromotive force measuring device 12, respectively, and these measurement signals are input to the tension estimation calculator 13. The tension estimation calculator 13 estimates the tension of the material 1 to be rolled from the motor armature current, the motor angular velocity and the motor back electromotive force by the method described above.

The estimated torque calculated from the estimated tension value is sent to the calculator 15. The calculator 15 calculates the deviation from the target torque, and the calculated deviation is the tension controller 14
Is input to The tension control device 14 is constructed as shown in FIG.

In the tension control device 14, the transient deviation between the tension and the target tension is reduced by the above-described method, by the state feedback of the estimated torque value estimated by the tension estimation calculator 13 and the motor angular velocity. Such a current command value is calculated, and the result is input to the current control device 9. And
The current controller 9 controls the winder drive motor 7 based on the current command value.

With this series of control operations, the tension of the material to be rolled is immediately controlled to the target tension by minimizing the transient error immediately after the tension is applied to the winder. Absent.

In order to verify the effect of the present invention, a control test of the hot rolling winder according to the present invention was conducted using the equipment of the embodiment shown in FIG. 1 (actual hot rolling equipment for steel sheet). . The results are shown in FIGS. As a comparison, FIGS. 5 and 6 show the test results when the control of the hot rolling winder according to the present invention is not carried out (when the conventional control as shown in FIG. 7 is carried out).

From the results shown in FIGS. 3 and 4, when the control of the hot rolling winder according to the present invention is carried out, the tension of the material to be rolled is controlled to almost the target tension at the same time when the winding is started. Therefore, it can be confirmed that the material to be rolled is not narrowed.

On the other hand, the results of the comparative examples shown in FIGS. 5 and 6 (when the control of the hot rolling winder according to the present invention is not carried out) show that the material to be rolled is wound around the winder. It indicates that an excessive tension is generated immediately after, and an error occurs between the tension and the target tension because the tension is not directly controlled during the subsequent winding. Therefore, it can be seen that the rolled material has a narrow width. The result of this comparative example is due to the fact that only the control of the armature current of the winder drive motor was carried out without paying attention to the fluctuation in tension of the material to be rolled.

[0047]

[Summary of Effects] As described above, according to the present invention, it is possible to easily and accurately prevent a narrow width that tends to occur when winding a material to be rolled after hot rolling without requiring expensive equipment. It is possible to produce suitable hot-rolled material with high yield and to produce industrially useful effects.

[Brief description of drawings]

FIG. 1 is an explanatory diagram related to a hot rolling facility for steel sheets used in an example.

FIG. 2 is an explanatory diagram related to a tension control device used in an example.

FIG. 3 is a graph showing “relationship between elapsed time and tension of rolled material” in actual machine control according to the present invention.

FIG. 4 is a graph showing “relationship between length position of rolled material and strip width deviation” in actual machine control according to the present invention.

FIG. 5 is a graph showing “relationship between elapsed time and tension of rolled material” in actual machine control by the conventional method.

FIG. 6 is a graph showing a “relationship between a rolled material length position and a strip width deviation” in actual machine control by a conventional method.

FIG. 7 is an explanatory diagram relating to a conventional method for controlling a hot rolling winder.

[Explanation of symbols]

 1 Rolled material 2 Hot finishing rolling mill group 3 Rolled material for sailing rolled material (table roller) 4 Pinch roll 5 Wrapper roll 6 Winder 7 Winder drive motor 8 Tension / current conversion device 9 Current control device 10 Current measuring device 11 Motor angular velocity measuring device 12 Motor counter electromotive force measuring device 13 Tension estimation calculator 14 Tension controller 15 calculator

Claims (1)

[Claims] 1. A method for controlling a hot rolling winder for preventing a narrow width of a rolled material generated when a rolled material exiting a hot finish rolling mill is wound into a coil by a winding machine. And an estimation calculator for estimating "tension generated in the material to be rolled between the finish rolling mill and the winding machine" from the rotation speed of the winding machine driving motor, the armature current and the back electromotive force, It is characterized in that the tension of the material to be rolled is controlled to the target tension by modifying the drive torque of the winder based on the estimated value of tension by the calculator, the rotation speed of the electric motor for driving the winder, and the armature current. , Control method of hot rolling and winding machine.