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UBC Theses and Dissertations
Adaptive control of sheet caliper on paper machines Li, Jing
Abstract
Caliper control is carried out in the calendering process in order to obtain even thickness of the sheet both in machine-direction and cross-direction. To control caliper, the local temperature of the calender rolls is manipulated. The relationship between temperature and caliper is nonlinear as heating and cooling must be represented by different linear processes. Both models feature timevarying parameters. The correlations among actuators across the roll are described in the interaction matrix of the CD model developed from mill data analysis. Generalized Predictive Control (GPC) is applied under system constraints in machine-direction (MD) and cross-machine direction (CD) control. This control algorithm can handle the timevarying parameters, couplings, and variable delays that are present in the caliper control system. The constrained optimal control signals of GPC are obtained by using the Lagrangian multiplier method. The on-line estimator is based upon Recursive Least Squares with Exponential Resetting and Forgetting factors. Simulations show satisfactory performance of constrained GPC in both MD and CD caliper control. The outputs track set-point changes closely and still have small variations even with parameter changes. Load disturbances added in the CD control system are rejected very well.
Item Metadata
Title |
Adaptive control of sheet caliper on paper machines
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Creator | |
Publisher |
University of British Columbia
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Date Issued |
1994
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Description |
Caliper control is carried out in the calendering process in order to obtain even thickness of
the sheet both in machine-direction and cross-direction. To control caliper, the local temperature of
the calender rolls is manipulated. The relationship between temperature and caliper is nonlinear as
heating and cooling must be represented by different linear processes. Both models feature timevarying
parameters. The correlations among actuators across the roll are described in the interaction
matrix of the CD model developed from mill data analysis.
Generalized Predictive Control (GPC) is applied under system constraints in machine-direction
(MD) and cross-machine direction (CD) control. This control algorithm can handle the timevarying
parameters, couplings, and variable delays that are present in the caliper control system.
The constrained optimal control signals of GPC are obtained by using the Lagrangian multiplier
method. The on-line estimator is based upon Recursive Least Squares with Exponential Resetting
and Forgetting factors.
Simulations show satisfactory performance of constrained GPC in both MD and CD caliper
control. The outputs track set-point changes closely and still have small variations even with parameter
changes. Load disturbances added in the CD control system are rejected very well.
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Extent |
3246665 bytes
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Genre | |
Type | |
File Format |
application/pdf
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Language |
eng
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Date Available |
2009-01-09
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Provider |
Vancouver : University of British Columbia Library
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Rights |
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
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DOI |
10.14288/1.0064866
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URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
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Graduation Date |
1995-05
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Campus | |
Scholarly Level |
Graduate
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Aggregated Source Repository |
DSpace
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Item Media
Item Citations and Data
Rights
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.