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Probing Control. Analysis and Design with Application to Fed-Batch Bioreactors

Velut, Stéphane LU (2005) In PhD Theses TFRT-1072.
Abstract (Swedish)
Popular Abstract in Swedish

I de flesta reglerproblem är syftet att hålla utsignalen nära ett önskat värde trots störningar som påverkar systemet. Ibland är det bästa referensvärdet inte känt i förväg. I stället skall det hittas i realtid för att optimera systemets prestanda. Denna avhandling behandlar en så kallade probing-strategi som kan tillämpas för denna klass av problem. Fokus ligger i tillämpning på reglering av feedtillförseln i fed-batch odlingar av bakterien Escherichia coli.



Avhandlingen består av tre delar. I första delen genomförs en analys av regulatorns konvergensegenskaper. Analysen är begränsad till processer som kan beskrivas av en statisk olinjäritet i serie med ett linjärt dynamiskt... (More)
Popular Abstract in Swedish

I de flesta reglerproblem är syftet att hålla utsignalen nära ett önskat värde trots störningar som påverkar systemet. Ibland är det bästa referensvärdet inte känt i förväg. I stället skall det hittas i realtid för att optimera systemets prestanda. Denna avhandling behandlar en så kallade probing-strategi som kan tillämpas för denna klass av problem. Fokus ligger i tillämpning på reglering av feedtillförseln i fed-batch odlingar av bakterien Escherichia coli.



Avhandlingen består av tre delar. I första delen genomförs en analys av regulatorns konvergensegenskaper. Analysen är begränsad till processer som kan beskrivas av en statisk olinjäritet i serie med ett linjärt dynamiskt system. Stabilitet och prestanda analyseras med hänsyn till processdynamiken. Enkla regler för att ställa in regulatorn ges också för att hjälpa användaren.



Andra delen beskriver en ny odlingsteknik baserad på probing-metoden. Tekniken kombinerar fördelarna av probing-metoden med en temperatur-begränsad reglering. Metoden är väl anpassad till odlingar i reaktorer som har en begränsad syreöverföringskapacitet. Odlingstekniken utvärderas med hjälp av simuleringar och experiment. Reglerstrategin leder till en hög celltäthet och visar sig minska den degradering av den rekombinanta produkten som ofta sker i den sena produktionsfasen.



I tredje delen av avhandlingen utvärderas probing-tekniken i industriella bioreaktorer. Inverkan av skalan och komplext

medium diskuteras med hjälp av experimentella data. Tekniken visar sig även här vara ett bra verktyg för processutveckling. (Less)
Abstract
In most control problems the objective is to control the output at a desired value in spite of disturbances. In some cases, the best setpoint is not known a priori and it should be found online to optimize the process performance. This thesis examines a probing strategy that can be applied for this class of problems. The focus is on the application of the technique to the control of feed supply in fed-batch fermentations of the bacterium Escherichia coli.



The thesis is divided into three parts. In the first part, the convergence properties of the probing algorithm are examined. The analysis is limited to processes modeled by a linear time-invariant dynamic in series with a static nonlinearity. Stability and performance... (More)
In most control problems the objective is to control the output at a desired value in spite of disturbances. In some cases, the best setpoint is not known a priori and it should be found online to optimize the process performance. This thesis examines a probing strategy that can be applied for this class of problems. The focus is on the application of the technique to the control of feed supply in fed-batch fermentations of the bacterium Escherichia coli.



The thesis is divided into three parts. In the first part, the convergence properties of the probing algorithm are examined. The analysis is limited to processes modeled by a linear time-invariant dynamic in series with a static nonlinearity. Stability and performance analysis taking into account the process dynamic is performed. Tuning guidelines that help the user for the design are also derived.



The second part presents a novel cultivation technique based on the probing approach. The fermentation technique combines the advantages of probing control and temperature-limited fed-batch technique. The feeding strategy is well adapted for prolonged operation at the maximum oxygen transfer capacity of the reactor. The efficiency of the method is demonstrated by simulations and experimental results. The strategy leads to a high biomass and it limits the degradation of the recombinant protein activity in the late production phase.



In the third part, the probing feeding strategy is evaluated in industrial-scale bioreactors. Based on experimental results the influence of scale and complex medium is discussed. It is shown that the flexibility and robustness of the technique makes it a useful tool for process development. (Less)
Please use this url to cite or link to this publication:
author
supervisor
opponent
  • Professor Allgöwer, Frank, University of Stuttgart
organization
publishing date
type
Thesis
publication status
published
subject
keywords
Elektronik och elektroteknik, Electronics and Electrical technology, Large scale fermentations, Extremum control, Feeding strategy, Probing control, Fed-batch bioreactors, Automation, robotics, control engineering, Automatiska system, robotteknik, reglerteknik
in
PhD Theses
volume
TFRT-1072
pages
141 pages
publisher
Department of Automatic Control, Lund Institute of Technology, Lund University
defense location
Room M:B, the M-building, Lund Institute of Technology
defense date
2005-06-03 13:15
ISSN
0280-5316
language
English
LU publication?
yes
id
e0b5169d-6543-4e2c-9256-45f1509a13a7 (old id 24605)
date added to LUP
2007-06-01 07:48:39
date last changed
2016-09-19 08:44:56
@phdthesis{e0b5169d-6543-4e2c-9256-45f1509a13a7,
  abstract     = {In most control problems the objective is to control the output at a desired value in spite of disturbances. In some cases, the best setpoint is not known a priori and it should be found online to optimize the process performance. This thesis examines a probing strategy that can be applied for this class of problems. The focus is on the application of the technique to the control of feed supply in fed-batch fermentations of the bacterium Escherichia coli.<br/><br>
<br/><br>
The thesis is divided into three parts. In the first part, the convergence properties of the probing algorithm are examined. The analysis is limited to processes modeled by a linear time-invariant dynamic in series with a static nonlinearity. Stability and performance analysis taking into account the process dynamic is performed. Tuning guidelines that help the user for the design are also derived.<br/><br>
<br/><br>
The second part presents a novel cultivation technique based on the probing approach. The fermentation technique combines the advantages of probing control and temperature-limited fed-batch technique. The feeding strategy is well adapted for prolonged operation at the maximum oxygen transfer capacity of the reactor. The efficiency of the method is demonstrated by simulations and experimental results. The strategy leads to a high biomass and it limits the degradation of the recombinant protein activity in the late production phase.<br/><br>
<br/><br>
In the third part, the probing feeding strategy is evaluated in industrial-scale bioreactors. Based on experimental results the influence of scale and complex medium is discussed. It is shown that the flexibility and robustness of the technique makes it a useful tool for process development.},
  author       = {Velut, Stéphane},
  issn         = {0280-5316},
  keyword      = {Elektronik och elektroteknik,Electronics and Electrical technology,Large scale fermentations,Extremum control,Feeding strategy,Probing control,Fed-batch bioreactors,Automation,robotics,control engineering,Automatiska system,robotteknik,reglerteknik},
  language     = {eng},
  pages        = {141},
  publisher    = {Department of Automatic Control, Lund Institute of Technology, Lund University},
  school       = {Lund University},
  series       = {PhD Theses},
  title        = {Probing Control. Analysis and Design with Application to Fed-Batch Bioreactors},
  volume       = {TFRT-1072},
  year         = {2005},
}