Control method for mill train

Patent metadata

Field	Value
Publication number	US-9751165-B2
Application number	US-201214119636-A
Country	US
Kind code	B2
Filing date	May 4, 2012
Priority date	May 24, 2011
Publication date	Sep 5, 2017
Grant date	Sep 5, 2017

Abstract

A current temperature is ascertained for sections of a strip ahead of a first mill stand. The temperatures of the strip sections are predicted with a prediction horizon corresponding to multiple strip sections, including when each strip section is milled in the first mill stand for which time a nip profile formed by the working rolls is predicted. A control parameter for milling a specific strip section in the first mill stand is ascertained for controlling a control device of the first mill stand. A manipulated variable curve for the control device, influencing the nip profile of a nip formed by working rolls of the first mill stand, is set for the prediction horizon and optimized for the predicted nip profile and a desired profile. The current value of the optimized manipulated variable curve corresponds to the control parameter which is fed to the control device as the manipulated variable.

First claim

The invention claimed is:

1. A control method for a rolling mill train, comprising:
determining actual temperatures of strip sections of a strip upstream of a first roll stand of the rolling mill train;
obtaining predicted temperatures of the strip sections for a time of rolling of a respective strip section in the first roll stand by a strip model based on the actual temperatures using a first prediction horizon which corresponds to a plurality of strip sections to be rolled in the first roll stand;
predicting a roll gap profile, formed by the work rolls of the first roll stand when the respective strip section is rolled, for the first roll stand by a roll stand model using the predicted temperatures of the strip sections and a manipulated variable characteristic that influences the roll gap profile, for the strip sections corresponding to the first prediction horizon;
optimizing the manipulated variable characteristic for the first prediction horizon based on the roll gap profile for the strip sections and a respective setpoint profile;
determining at least one control parameter for rolling of the respective strip section in the first roll stand using the predicted temperatures of the strip sections, based on a current value of the optimized manipulated variable characteristic; and
controlling an adjusting device acting on the first roll stand during rolling of the respective strip section taking the at least one control parameter into account, the adjusting device including an operator-side roll gap control system influencing the roll gap on an operator side of the first roll stand and a drive side roll gap control system influencing the roll gap on a drive side of the first roll stand, said controlling including
predicting a respective current operator-side material modulus and a respective current drive-side material modulus for the strip sections, using the predicted temperatures for a time of the rolling of the respective strip section in the first roll stand, and
parameterizing the operator- and drive-side roll gap control system at the time when the respective strip section is rolled in the first roll stand using material moduli corresponding to the control parameters.

2. The control method as claimed in claim 1 ,
further comprising predicting a rolling force required for rolling the respective strip section in the first roll stand by a rolling force model using at least the predicted temperatures for the strip sections corresponding to the first prediction horizon, and
wherein the roll gap profile is predicted by the roll stand model using the predicted rolling force from the rolling force model.

3. The control method as claimed in claim 2 , wherein the adjusting device comprises a roll cooling device controlled in a spatially resolved manner in a strip width direction.

4. The control method as claimed in claim 3 ,
wherein the control method is also carried out for a second roll stand downstream of the first roll stand of the rolling mill train using a second prediction horizon, and
wherein the strip sections are rolled from a first entry thickness to a first exit thickness in the first roll stand and from a second entry thickness to a second exit thickness in the second roll stand.

5. The control method as claimed in claim 4 , wherein at least one of the first exit thickness and the second entry thickness is determined on a strip section specific basis.

6. The control method as claimed in claim 5 , wherein the second prediction horizon is dimensioned such that during the second prediction horizon a plurality of strip sections are rolled both in the first roll stand and in the second roll stand.

7. The control method as claimed in claim 1 ,
wherein the strip model includes a material model by which an expectable material property other than the temperature is predicted for the strip sections to be rolled in the first roll stand for the time of rolling of the respective strip section in the first roll stand, and
wherein the predicted material properties are taken into account in determining the at least one control parameter.

8. The control method as claimed in claim 7 , wherein the temperatures of the strip sections predicted by the strip model are spatially resolved in the strip width direction.

9. The control method as claimed in claim 8 , wherein the temperatures determined for the strip sections are spatially resolved in the strip width direction.

10. The control method as claimed in claim 9 ,
further comprising parameterizing at least one of the strip model and another model used as part of determining the at least one control parameter, based on a model parameter, as a parameterizable model,
wherein said determining of the at least one control parameter uses the parameterizable model to determine variables and functional dependences of the variables based on the model parameter in real time,
further comprising determining an expected value for a measured value and a functional dependence of the expected value on the model parameter for the strip sections in real time using the variables determined by the parameterizable model,
wherein measured values of the strip sections are respectively determined in real time by a measuring device disposed one of upstream, on and downstream of the first roll stand, further comprising:
re-determining the model parameter based on one of the measured values, the expected value and the functional dependence of the expected value on the model parameter,
re-parameterizing the parameterizable model based on a re-determined model parameter, and
adjusting the variables already determined for the strip sections in real time as part of determining the at least one control parameter using the parameterizable model.

11. A non-transitory computer readable medium embodying machine code directly executable by a control computer for a rolling mill train which causes the control computer to carry out a control method comprising:
determining actual temperatures of strip sections of a strip upstream of a first roll stand of the rolling mill train;
obtaining predicted temperatures of the strip sections for a time of rolling of a respective strip section in the first roll stand by a strip model based on the actual temperatures using a first prediction horizon which corresponds to a plurality of strip sections to be rolled in the first roll stand;
predicting a roll gap profile, formed by the work rolls of the first roll stand when the respective strip section is rolled, for the first roll stand by a roll stand model using the predicted temperatures of the strip sections and a manipulated variable characteristic that influences the roll gap profile, for the strip sections corresponding to the first prediction horizon;
optimizing the manipulated variable characteristic for the first prediction horizon based on the roll gap profile for the strip sections and a respective setpoint profile;
determining at least one control parameter for rolling of the respective strip section in the first roll stand using the predicted temperatures of the strip sections, based on a current value of the optimized manipulated variable characteristic; and
controlling an adjusting device acting on the first roll stand during rolling of the respective strip section taking the at least one control parameter into account, the adjusting device including an operator-side roll gap control system influencing a roll gap on an operator side of the first roll stand and a drive side roll gap control system influencing the roll gap on a drive side of the first roll stand, said controlling including
predicting a respective current operator-side material modulus and a respective

Assignees

• Dagner Johannes
• GRüSS ANSGAR
• Primetals Technologies Germany Gmbh

Inventors

• Dagner Johannes
• GRüSS ANSGAR

Classifications

• B21B37/58 Primary

  Roll-force control; Roll-gap control {(B21B38/105 takes precedence)} · CPC title

• B21B2261/21

  Temperature profile · CPC title

• B23P17/00 Primary

  Metal-working operations, not covered by a single other subclass or another group in this subclass · CPC title

• B21B2271/02

  Roll gap, screw-down position, draft position · CPC title