JP2000084615A - Method for controlling tension in rolling mill - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately control tension without impeding production by measuring a prescribed data during rolling, preparing a mechanical loss table and executing the tension control of a tension reel by using the table. SOLUTION: Actual tension Tact and set tension Tset are inputted to a system control part 12 and a speed signal Vs is inputted to a control circuit 10 and mechanical loss memory 11. In the system control part 12, difference between a tension error (Tact-Tset) and the set tension Tset is determined. This difference (2×Tset-Tact) is expressed in terms of electric current and expressed by Iset. By adding the Iset and the set value Imset of the mechanical loss, (Iset+Imset) is made and outputted to a motor control circuit 10. By repeating these operations, the mechanical loss Im corresponding to the speed Vs is updated, the mechanical loss table is automatically produced (updated) during rolling and the tension control is executed by using the updated mechanical loss table.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling the tension of a rolling mill in reverse rolling or the like.

[0002]

2. Description of the Related Art In reverse rolling of a thin plate, tension control by a tension reel is performed in order to improve the thickness accuracy. In the tension control by the tension reel, the armature current Ia of the tension reel motor is controlled so that the tension of the rolled material is constant. The armature current Ia is composed of a tension current It consumed for tension and a mechanical loss current Im consumed for friction of the machine.
a = It + Im. Therefore, in order to control the tension to be constant, the tension current It must be constant, and for that purpose, the mechanical loss current Im must be known.

Conventionally, as a technique for measuring the mechanical loss current Im, a technique disclosed in Japanese Patent Publication No. 6-96163 is known. This conventional technique measures the rotation speed and the mechanical loss current of the tension reel independently while rolling is stopped, creates a mechanical loss table as shown in FIG. The tension current was controlled to be constant by obtaining the mechanical loss from this table.

[0004]

The above-mentioned prior art measures the mechanical loss of the tension reel while the rolling is stopped, thus causing a decrease in productivity. Further, since the measured mechanical loss was during the rolling stop, it was slightly different from that during the actual rolling, and the precision of the tension control was deteriorated.

[0005] Therefore, an object of the present invention is to provide a tension control method in a rolling equipment which solves the above-mentioned problems by measuring mechanical loss during rolling.

[0006]

In order to achieve the above object, the present invention takes the following measures. That is, a feature of the present invention is that, in a rolling plant including a rolling mill and a tension reel for winding a rolled material rolled by the rolling mill, a predetermined data is measured during rolling to obtain a machine. The point is that a loss table is created and the tension control of the tension reel is performed using the table.

The mechanical loss table is preferably created based on the rotational speed of the electric motor for the tension reel during rolling, and the correlation between the actual tension from the tension meter and the mechanical loss obtained from the set tension value. . According to the method of the present invention, since the mechanical loss can be determined during rolling, productivity is improved, and the actual mechanical loss during rolling is measured, so that accurate tension control becomes possible. Product quality is improved.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, a sheet reverse rolling mill
1 is provided with a tension reel 3 for rewinding and winding the rolled material 2.
A deflector roll 4 is arranged between the three. The deflector roll 4 is supported via a tensiometer 5.
The tension reel 3 is connected to an electric motor 7 via a speed reducer 6.
It is driven by. This motor 7 is provided with a speed detector 8. The tension meter 5, the electric motor 7 and the speed detector 8 are connected to a control device 9.

As shown in FIG. 2, the control unit 9 includes a motor control circuit 10, a mechanical loss memory 11, a system control unit 12
And constitutes a mechanical loss automatic recording device for the tension reel motor 7. The motor 7 is composed of a DC motor. The constant tension control by the motor 7 is performed by setting the armature current Ia constant and setting the back electromotive voltage E or the field magnetic flux φ as shown in the following equations (5) and (6). Is controlled by the control device 9.

Here, the basic formula of the tension control is shown. The winding tension Te (kg) is expressed by the following equation. Te = K1.T / D (1) where K1: proportional constant D: coil diameter (m) T: torque (kgm) Winding speed V (mpm) is expressed by the following equation.

V = K 2 · D · N (2) where K 2: proportionality constant N: rotation speed (rpm) Motor torque T (kgm) is expressed by the following equation. T = K3 · φ · Ia (3) where K3: proportionality constant φ: field magnetic flux (wb) Back electromotive force E (v) is expressed by the following equation.

E = K 4 · φ · N (4) where K 4: proportionality constant From the above equations (1) to (4), the following equation is obtained. Te = K5 · (E / V) · Ia (5) = K6 · (φ / D) · Ia (6) The armature current Ia is a tension current It consumed by tension.
(Ia = It + Im), and the armature current Ia is controlled such that the tension current It is constant during tension control. For that purpose, the mechanical loss current Im must be known.

The mechanical loss memory 11 initially stores an initial mechanical loss table as shown in FIG. 5 as initial value data. In the present invention, in the automatic mechanical loss recording apparatus, the initial value data is updated during rolling, and a new mechanical loss table is created and updated. Then, with reference to the mechanical loss table generated by the automatic mechanical loss recording device, constant tension control of the tension reel of the tension reel motor 7 is performed.

The procedure for updating the mechanical loss table will be described with reference to the flowcharts of FIGS. First, during rolling, the actual tension Tact measured by the tensiometer 5 and the set tension Tact set by the setting device are read, and the motor speed Vs measured by the speed detector 8 is read.

The actual tension Tact and the set tension Tact are:
The speed signal Vs input to the system control unit 12 is
It is input to the control circuit 10 and the mechanical loss memory 11. The speed signal Vs changes according to a change in the coil diameter. The current supplied from the control circuit 10 to the electric motor 7 is fed back to the control circuit 10. The role of the system control unit 12 is to output a current command to the motor control circuit 10 and to output a current conversion value ΔI of a tension error to the mechanical loss memory 11.

That is, the input actual tension Tact and the tension set value T
Find the difference of set. This difference is the tension error (= Tact−Tse)
t). This tension error is converted into a current to determine ΔI. This current conversion is performed based on the above equation (5) or (6). The meaning of the tension error (= Tact-Tset) is that this tension error has occurred due to mechanical loss. Therefore, the current conversion value ΔI is a mechanical loss.

Therefore, in the mechanical loss memory 11,
With respect to the current mechanical loss Im at the motor speed Vs, Im ← Im + ΔI is updated as a new mechanical loss Im as the mechanical loss Im at the motor speed Vs and stored in the memory. Then, this updated new mechanical loss Im
Is output to the system control unit 12 as the mechanical loss set value Imset.

In the system controller 12, a tension error (Tact
−Tset) and the set tension Tset. This is Tset− (Tact−Tset) = 2 × Tset−Tact
Becomes If this is set as a command, the tension error becomes zero. The tension command (2 × Tset−Tact) is converted into a current based on the above equation (5) or (6) to obtain Iset. Then, the command Iset corresponding to the tension and the set value Imset of the mechanical loss are added and output to the motor control circuit 10 as Iset + Imset.

By repeating the above operation, the motor speed Vs changes with a change in the winding diameter, so that the mechanical loss Im corresponding to the speed Vs is updated in the mechanical loss memory 11. That is, in the present invention, the mechanical loss table is automatically generated (updated) during rolling.

The function of the system control circuit 12 can be realized by using, for example, a microcomputer. The current feedback to the motor control circuit 10 is to match with a current command to the motor control circuit 10, and is taken in by the motor control circuit 10 to maintain the current to the motor as instructed. . The motor speed Vs is used for turning the motor under speed control.

Note that, as shown in FIG.
Are inclined with respect to the direction of gravity so that the tension Te acts vertically. Therefore, there is a problem that the component force B of the gravity A, which is perpendicular to the tension meter 5, changes due to the temperature drift with the passage of time, and the tension Te cannot be measured accurately due to the influence. When such a temperature drift becomes a problem, the tension measurement by the tensiometer 5 is performed in the first pass at the beginning of rolling of one coil. That is, the mechanical loss table is updated in the first pass, and in subsequent passes, the tension control is performed using the updated mechanical loss table. Whether or not to measure the next coil is determined by the operator.

The present invention is not limited to the above embodiment.

[0023]

According to the present invention, since the mechanical loss can be measured during rolling, that is, during production, production is not hindered. In addition, accurate mechanical loss can be measured. This is different from the measured value during the rolling stop because the point that can be measured at all times during the production and the mechanical loss during the rolling are affected by the tension. In the present invention, since the measurement can be performed during rolling, accurate tension control can be performed.

[Brief description of the drawings]

FIG. 1 is a block diagram of an apparatus for using the method of the present invention.

FIG. 2 is a block diagram illustrating details of a control device illustrated in FIG. 1;

FIG. 3 is a flowchart illustrating a procedure of updating a mechanical loss table.

FIG. 4 is an explanatory diagram showing a force relationship acting on a tensiometer.

FIG. 5 is a graph showing an example of a mechanical loss table.

[Description of Signs] 1 Rolling machine 2 Rolled material 3 Tension reel 5 Tensiometer

Claims (2)

[Claims] In a rolling facility including a rolling mill and a tension reel for winding a rolled material rolled by the rolling mill, predetermined data is measured during rolling to reduce a mechanical loss table of the tension reel. A tension control method for a rolling mill, wherein the tension control is performed using the table. 2. The mechanical loss table is prepared based on the rotational speed of the tension reel motor during rolling, and the correlation between the actual tension from the tension meter and the mechanical loss obtained from the set tension value. The tension control method for a rolling mill according to claim 1, wherein: