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Thickness control for a plate mill

Pedersen, Lars Malcolm and Wittenmark, Björn LU (1998) Automation in Mining Mineral and Metal Processing, IFAC p.331-336
Abstract
The purpose of this paper is to describe the design of a multivariable control law for a hot plate mill. The design is performed on models adapted to the plate mill at The Danish Steel Work Ltd. The model for the rolling mill is divided into nonlinear models for the hydraulic systems performing the thickness control and a multivariable linear model for the rolling stand. The parameters of the models are found using measurements from the rolling mill at The Danish Steel Work Ltd. Most of the measurements are collected during rolling, but plate thickness measurements are performed after rolling using special equipment. In general, good agreement is obtained between measurements and model outputs. The multivariable nonlinaer model is used for... (More)
The purpose of this paper is to describe the design of a multivariable control law for a hot plate mill. The design is performed on models adapted to the plate mill at The Danish Steel Work Ltd. The model for the rolling mill is divided into nonlinear models for the hydraulic systems performing the thickness control and a multivariable linear model for the rolling stand. The parameters of the models are found using measurements from the rolling mill at The Danish Steel Work Ltd. Most of the measurements are collected during rolling, but plate thickness measurements are performed after rolling using special equipment. In general, good agreement is obtained between measurements and model outputs. The multivariable nonlinaer model is used for designing a multivarialbe thickness control law which can be seen as an unified approach to control mean thickness and plate wedge. The result is a second order nonlinear controller with rolling forces and roll positions as inputs and control signal to the servo valves as outputs. Since it is not possible to implement the multivariable control law for the time being, the multivariable control law is simplified with the purpose of using it as a basis for an optimization of the existing thickness control equipment at The Danish Steel Works Ltd. This optimization can be seen as the first step in the practical verification of the multivariable control law. (Less)
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organization
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type
Contribution to conference
publication status
published
subject
keywords
Nonlinear control, system identification, rolling mill, steel industry
pages
331 - 336
conference name
Automation in Mining Mineral and Metal Processing, IFAC
language
English
LU publication?
yes
id
4c36cdfc-6464-4ef7-bcf1-290313eba1cc (old id 4780470)
date added to LUP
2014-11-23 11:18:43
date last changed
2016-04-16 11:09:49
@misc{4c36cdfc-6464-4ef7-bcf1-290313eba1cc,
  abstract     = {The purpose of this paper is to describe the design of a multivariable control law for a hot plate mill. The design is performed on models adapted to the plate mill at The Danish Steel Work Ltd. The model for the rolling mill is divided into nonlinear models for the hydraulic systems performing the thickness control and a multivariable linear model for the rolling stand. The parameters of the models are found using measurements from the rolling mill at The Danish Steel Work Ltd. Most of the measurements are collected during rolling, but plate thickness measurements are performed after rolling using special equipment. In general, good agreement is obtained between measurements and model outputs. The multivariable nonlinaer model is used for designing a multivarialbe thickness control law which can be seen as an unified approach to control mean thickness and plate wedge. The result is a second order nonlinear controller with rolling forces and roll positions as inputs and control signal to the servo valves as outputs. Since it is not possible to implement the multivariable control law for the time being, the multivariable control law is simplified with the purpose of using it as a basis for an optimization of the existing thickness control equipment at The Danish Steel Works Ltd. This optimization can be seen as the first step in the practical verification of the multivariable control law.},
  author       = {Pedersen, Lars Malcolm and Wittenmark, Björn},
  keyword      = {Nonlinear control,system identification,rolling mill,steel industry},
  language     = {eng},
  pages        = {331--336},
  title        = {Thickness control for a plate mill},
  year         = {1998},
}