Article | Proceedings of the 10<sup>th</sup> International Modelica Conference; March 10-12; 2014; Lund; Sweden | Symbolic Initialization of Over-determined Higher-index Models Link�ping University Electronic Press Conference Proceedings
Göm menyn

Title:
Symbolic Initialization of Over-determined Higher-index Models
Author:
Lennart Ochel: Bielefeld University of Applied Sciences, Department of Mathematics and Engineering, Bielefeld, Germany Bernhard Bachmann: Bielefeld University of Applied Sciences, Department of Mathematics and Engineering, Bielefeld, Germany Francesco Casella: Politecnico di Milano, Dipartimento di Elettronica, Informazione e Bioingegneria, Milano, Italy
DOI:
10.3384/ecp140961179
Download:
Full text (pdf)
Year:
2014
Conference:
Proceedings of the 10th International Modelica Conference; March 10-12; 2014; Lund; Sweden
Issue:
096
Article no.:
124
Pages:
1179-1187
No. of pages:
9
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


Export in BibTex, RIS or text

The amount of needed initial equations in an object-oriented model can only be determined at system level. Because Modelica models are generally designed by components; it is hard to figure out all needed initial conditions at system level; even more when changes are applied to the model; e.g. by adding or removing components. Hence; it is more convenient to define initial equations at component level. Due to component connections; algebraic dependencies between states may be introduced; which eventually lead to the removal of states when symbolic index reduction algorithms are applied. In this process the corresponding initial equations are not automatically removed and an over-determined initial system ensues.

This paper describes an algorithm that detects such redundant equations and determines if they are consistent or not. Consistent redundant initial equations can thus be removed automatically; and inconsistent ones can be reported to the modeler. The algorithm is implemented in OpenModelica; tested on several representative cases; and compared to previously presented concepts.

Keywords: Initialization; higher-index; simulation; over-constrained

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

Author:
Lennart Ochel, Bernhard Bachmann, Francesco Casella
Title:
Symbolic Initialization of Over-determined Higher-index Models
DOI:
http://dx.doi.org/10.3384/ecp140961179
References:

[1] B. Bachmann, P. Aronsson, P. Fritzson, "Robust Initialization of Differential-Algebraic Equations", In Proceedings 5th International Modelica Conference, Vienna, Austria, Sep. 4-5, 2006, pp. 607-614

[2] L. Ochel, B. Bachmann, "Initialization of Equation-Based Hybrid Models within Open-Modelica", In EOOLT 2013 Proceedings, Nottingham, UK, April 19, 2013, pp. 97-103

[3] C.C. Pantelides, The Consistent Initialization of Differential-algebraic Systems. SIAM Journal on Scientific and Statistical Computing, Vol. 9, No. 2, 1988

[4] S.E. Mattsson, G. Söderlind, Index Reduction in Differential-algebraic Equations Using Dummy Derivatives. SIAM Journal on Scientific Computing, Vol. 14, No. 3, 1993

[5] R. Tarjan, Depth-first search and linear graph algorithms. SIAM Journal on Computation, Vol. 1, No. 2, 1972

[6] F.E. Cellier, E. Kofman, Continuous System Simulation, Springer, 2006

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

Author:
Lennart Ochel, Bernhard Bachmann, Francesco Casella
Title:
Symbolic Initialization of Over-determined Higher-index Models
DOI:
http://dx.doi.org/10.3384/ecp140961179
Note: the following are taken directly from CrossRef
Citations:
No citations available at the moment


Responsible for this page: Peter Berkesand
Last updated: 2018-9-11