Article | Proceedings of the 10<sup>th</sup> International Modelica Conference; March 10-12; 2014; Lund; Sweden | Symbolic Transformations of Dynamic Optimization Problems
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Title:
Symbolic Transformations of Dynamic Optimization Problems
Author:
Fredrik Magnusson: Department of Automatic Control, Lund University, Lund, Sweden Karl Berntorp: Department of Automatic Control, Lund University, Lund, Sweden Björn Olofsson: Department of Automatic Control, Lund University, Lund, Sweden Johan Åkesson: Department of Automatic Control, Lund University, Lund, Sweden/Modelon AB, Ideon Science Park, Lund, Sweden
DOI:
10.3384/ecp140961027
Download:
Full text (pdf)
Year:
2014
Conference:
Proceedings of the 10th International Modelica Conference; March 10-12; 2014; Lund; Sweden
Issue:
096
Article no.:
107
Pages:
1027-1036
No. of pages:
10
Publication type:
Abstract and Fulltext
Published:
2014-03-10
ISBN:
978-91-7519-380-9
Series:
Linköping Electronic Conference Proceedings
ISSN (print):
1650-3686
ISSN (online):
1650-3740
Publisher:
Linköping University Electronic Press; Linköpings universitet


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Dynamic optimization problems involving differential-algebraic equation (DAE) systems are traditionally solved while retaining the semi-explicit or implicit form of the DAE. We instead consider symbolically transforming the DAE into an ordinary differential equation (ODE) before solving the optimization problem using a collocation method. We present a method for achieving this; which handles DAE-constrained optimization problems. The method is based on techniques commonly used in Modelica tools for simulation of DAE systems.

The method is evaluated on two industrially relevant benchmark problems. The first is about vehicletrajectory generation and the second involves startup of power plants. The problems are solved using both the DAE formulation and the ODE formulation and the performance of the two approaches is compared. The ODE formulation is shown to have roughly three times shorter execution time. We also discuss benefits and drawbacks of the two approaches.

Keywords: Dynamic optimization; symbolic transformations; causalization; collocation

Proceedings of the 10th International Modelica Conference; March 10-12; 2014; Lund; Sweden

Author:
Fredrik Magnusson, Karl Berntorp, Björn Olofsson, Johan Åkesson
Title:
Symbolic Transformations of Dynamic Optimization Problems
DOI:
http://dx.doi.org/10.3384/ecp140961027
References:

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Proceedings of the 10th International Modelica Conference; March 10-12; 2014; Lund; Sweden

Author:
Fredrik Magnusson, Karl Berntorp, Björn Olofsson, Johan Åkesson
Title:
Symbolic Transformations of Dynamic Optimization Problems
DOI:
http://dx.doi.org/10.3384/ecp140961027
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