Method for tension control

Patent metadata

Field	Value
Publication number	US-11426778-B2
Application number	US-201816477570-A
Country	US
Kind code	B2
Filing date	Jan 12, 2018
Priority date	Jan 16, 2017
Publication date	Aug 30, 2022
Grant date	Aug 30, 2022

Abstract

A method for tension control in a band-shaped material between two tension points, in particular between two adjacent roll stands, wherein at least one of the tension points has a rotary drive as an actuator. In order to make known tension controls of this type more effective and faster the controller output signal is varied in connection with the conversion thereof into the actuating signal for the rotary drive, at least temporarily, in dependence on a variable representing the band-shaped material.

First claim

The invention claimed is:

1. A method for tension control in a band-shaped material between two clamping points, wherein the two clamping points are two neighboring rolling stands of a rolling mill, wherein at least one of the rolling stands comprises a rotary drive for driving rotation of one roll of the roll stand or wherein one of the two clamping points is a pair of rolls and the other of the two clamping points is a coiling device downstream in a rolling direction, wherein the pair of rolls comprises the rotary drive for driving the rotation of a least one of the rolls and/or the coiling device comprises the rotary drive for driving rotation of a coil, the method comprising the steps of:
determining actual tension between the two clamping points;
comparing the actual tension and a given desired tension in a comparator to determine a control error e(t) as a difference between the actual tension and a given desired tension;
entering the control error e(t) on a controller to generate a controller output signal R(t);
converting the controller output signal R(t) into an actuating signal S(t) with a conversion device;
varying speed of the rotary drive as an actuating element in accordance with the actuating signal S(t) to regulate the actual tension to the desired tension of the band-shaped material in the rolling mill;
and varying the controller output signal R(t) in connection with the conversion into the actuating signal S(t) by the conversion device at least temporarily in dependence on a variable g(t) representing speed of the band-shaped material, the method including, in a first variant:
forming with the conversion device a gain factor V(t):

V
⁡
(
t
)

=

g
⁡
(
t
)

g
⁡
(

t
0

)

,

(
1
)

which represents a curve of the variable g(t) representing the speed of the band-shaped material plotted against time, normalized to a given constant g(t 0 ); and forming the actuating signal S(t) by the following formula:

S
⁡
(
t
)

=

R
⁡
(
t
)

-

∑

t
i

≤
t

(

A
1

(

t
i

)

)

+

g
⁡
(
t
)

g
⁡
(

t
0

)

*

∑

t
i

≤
t

(

A
1

(

t
i

)

V
⁡
(

t
i

)

)

(
2
)

with:
A1(t0) given
Z(t0) given
t i : learning times
t 0 : first learning time.

2. The method according to claim 1 , wherein times at which the variable g(t) representing the speed of the band-shaped material each reach a given threshold value g LPi , or
at which the variable g(t) representing the speed of the band-shaped material is no longer constant, but begins to change so that dg(t)/dt≠0 or
at which magnitude of Al(t)—during an acceleration phase of the band-shaped material—goes beyond a given threshold value A 1max ,
are set respectively as the learning times t i .

3. The method according to claim 1 , wherein the actuating signal (S(t)) is computed by formula (2) in the conversion device, when the variable g(t) representing the speed of the band-shaped material falls below a given upper threshold value g max and goes beyond a given lower threshold value g min .

4. The method according to claim 1 , including operating the tension control in a second variant so that a gain factor V(t) is formed by the conversion device as:

Assignees

• Sms Group Gmbh

Inventors

• Sieghart Jörn
• Peters Ronny

Classifications

• B21B37/46

  Roll speed or drive motor control (B21B37/52, B21B37/60 take precedence) · CPC title

• B21B37/52 Primary

  by drive motor control · CPC title

• B21B2275/08

  Coiler speed · CPC title

• B21B2275/06

  Product speed · CPC title

• B21B2275/02

  Speed · CPC title