Collocation Methods for Optimization in a Modelica Environment

Summary, in English

The solution of generic dynamic optimization problems described by Modelica, and its extension Optimica, code using direct collocation methods is discussed. We start by providing a description of dynamic optimization problems in general and how to solve them by means of direct collocation. Next, an existing implementation of a collocation algorithm in JModelica.org, using CasADi and IPOPT, is presented. The extensions made to this implementation are reported.



The new implementation is compared to an old C-based collocation algorithm in JModelica.org in two benchmarks. The presented benchmarks are based on a continuously stirred tank reactor and a combined cycle power plant. The new algorithm and its surrounding framework is more flexible and shown to be several times more efficient than its predecessor.

• Author: Fredrik Magnusson; Johan Åkesson
• Editor: Martin Otter; Dirk Zimmer
• Department/s: Department of Automatic Control; ELLIIT: the Linköping-Lund initiative on IT and mobile communication
• Publishing year: 2012
• Language: English
• Pages: 649-658
• Publication/Series: Linköping Electronic Conference Proceedings
• Issue: 76
• Full text: - 248 kB; Download statistics
• Document type: Conference paper
• Publisher: Linköping University Electronic Press
• Topic: Control Engineering
• Keywords: dynamic optimization; JModelica.org; collocation; nonlinear programming; CasADi
• Conference name: 9th International Modelica Conference
• Conference date: 2012-09-03
• Conference place: Munich, Germany
• Status: Published
• Project: LCCC; Numerical and Symbolic Algorithms for Dynamic Optimization
• Research group: LCCC
• ISBN/ISSN/Other: ISSN: 1650-3686; ISSN: 1650-3740; ISBN: 978-91-7519-826-2