Planned maintenance
A system upgrade is planned for 10/12-2024, at 12:00-13:00. During this time DiVA will be unavailable.
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Sensitivity of variable pairing in multivariable process control to model uncertainties
2007 (English)Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
Abstract [en]

This project proposes a method for obtaining the variations in the Relative Gain Array (RGA) due to uncertainties in models of 2x2 multivariable systems. The uncertainties are represented as element by element multiplicative uncertainty using the Schur multiplier. An introduction and some references about the background of the project are given, the topics are: uncertainties, decentralized control, decoupling, and interaction measures, with a deeper overview of the RGA. The conclusions obtained about uncertainties and RGA are applied to some 2x2 examples which illustrate the following cases: A diagonally dominant system, with values of the RGA close to 1 for the diagonal elements. The RGA of these systems is the most robust to uncertainties: it's robustness is shown, and an example about this reliability is given. A system with large values of the RGA. Large values of the RGA are usually advised against pairing purposes because they are related to ill-conditioned plants: nevertheless, it is not clear how large can these values be and still be used for pairing purposes. These systems are the most sensible to uncertainties, and the larger the values of the RGA are, the higher sensitivity of the RGA to uncertainties. An analysis of the sensitivity of these systems is made in order to suggest upper bounds for the values of the nominal RGA. Values of the RGA above these ones will be considered highly sensitive to uncertainties, therefore, small perturbations can yield to large values of the RGA, and they should be discarded for pairing purposes. A system with positive values of the RGA moderately lower than 1 for the diagonal elements. Take as an example a system with value 0.8 for the element lambda_{11} of the nominal RGA: this value is usually taken as valid for pairing purposes, but, can perturbations modify the value of the RGA in such a way that the results would not be valid for pairing purposes?. A system with these characteristics is introduced, and a method for analyzing the bounds of the RGA due to uncertainties is proposed.

Place, publisher, year, edition, pages
2007.
Keywords [en]
Technology, RGA, interaction measures, decentralized control, uncertainties, interaction, sensitivity
Keywords [sv]
Teknik
Identifiers
URN: urn:nbn:se:ltu:diva-42989ISRN: LTU-PB-EX--07/068--SELocal ID: 0ebcbc0f-eb94-4afc-9c31-901c148c3015OAI: oai:DiVA.org:ltu-42989DiVA, id: diva2:1016216
Subject / course
Student thesis, at least 15 credits
Educational program
Electrical Engineering, master's level
Examiners
Note
Validerat; 20101217 (root)Available from: 2016-10-04 Created: 2016-10-04Bibliographically approved

Open Access in DiVA

fulltext(1688 kB)460 downloads
File information
File name FULLTEXT01.pdfFile size 1688 kBChecksum SHA-512
0a090b14aebf143e8e26f441b8451c65a4c567485d3e9f988a196087b2c895dbf6a48cb0ddcf64cf2e88e6459c418b1cdc10189c9569299c198b010c86d46de1
Type fulltextMimetype application/pdf

Search outside of DiVA

GoogleGoogle Scholar
Total: 460 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

urn-nbn

Altmetric score

urn-nbn
Total: 75 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf