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UBC Theses and Dissertations
Cross directional control of basis weight on paper machines using Gram polynomials Kristinsson, Kristinn
Abstract
In this thesis a control algorithm for cross-directional basis weight control based on orthogonal polynomials is presented. Instead of controlling the cross-directional values at each point, the parameters of the orthogonal polynomials are controlled, taking into account the maximum bending moment of the slice lip and the relative stiffness of the slice with respect to the actuators. Problems with slice lip bending are dealt with in two ways. Implicitly, by modelling it as a polynomial such that the slice is not bent more than the highest degree of the polynomial, which is chosen beforehand. Explicitly, by calculating the bending moment and then use quadratic programming to limit the bending moment. By modeling the measurements and the actuators positions by polynomials the mapping between the actuators and the sensors, which is the key element of the current control systems, is effectively eliminated. Computational requirements are greatly reduced by avoiding inverses of big matrices.
Item Metadata
Title |
Cross directional control of basis weight on paper machines using Gram polynomials
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Creator | |
Publisher |
University of British Columbia
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Date Issued |
1994
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Description |
In this thesis a control algorithm for cross-directional basis weight control based on orthogonal
polynomials is presented. Instead of controlling the cross-directional values at each point, the
parameters of the orthogonal polynomials are controlled, taking into account the maximum bending
moment of the slice lip and the relative stiffness of the slice with respect to the actuators. Problems
with slice lip bending are dealt with in two ways. Implicitly, by modelling it as a polynomial such
that the slice is not bent more than the highest degree of the polynomial, which is chosen beforehand.
Explicitly, by calculating the bending moment and then use quadratic programming to limit the
bending moment. By modeling the measurements and the actuators positions by polynomials the
mapping between the actuators and the sensors, which is the key element of the current control
systems, is effectively eliminated. Computational requirements are greatly reduced by avoiding
inverses of big matrices.
|
Extent |
6693958 bytes
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Genre | |
Type | |
File Format |
application/pdf
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Language |
eng
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Date Available |
2009-04-08
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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 |
10.14288/1.0065251
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URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
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Graduation Date |
1994-05
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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.