Generation of initial estimates for Wiener-Hammerstein models via basis function expansions

Koen Tiels, Maarten Schoukens, Joannes Schoukens

Research output: Chapter in Book/Report/Conference proceedingConference paper

4 Citations (Scopus)

Abstract

Block-oriented models are often used to model nonlinear systems. They consist of linear dynamic (L) and nonlinear static (N) sub-blocks. This paper proposes a method to generate initial values for a Wiener-Hammerstein model (LNL cascade). The method starts from the best linear approximation (BLA) of the system, which provides an estimate of the product of the transfer functions of the two linear dynamic sub-blocks. Next, the poles of the BLA are assigned to both linear dynamic sub-blocks. The linear dynamics are then parameterized in terms of rational orthonormal basis functions, while the nonlinear sub-block is parameterized by a polynomial. This allows to reformulate the model to the cascade of a parallel Wiener (with parallel LN structure) and a linear dynamic system, which is bilinear in its parameters. After a bilinear optimization, the parallel Wiener part is projected to a single-branch Wiener model. The approach is illustrated on a simulation example.
Original languageEnglish
Title of host publicationProceedings of 19th IFAC World Congress, Cape Town (South Africa), August 24-29, 2014
PublisherElsevier
Pages481–486
ISBN (Electronic)978-3-902823-62-5
Publication statusPublished - 24 Aug 2014
Event19th World Congress of the International Federation of Automatic Control (IFAC 2014) - Cape Town, South Africa
Duration: 24 Aug 201429 Aug 2014

Publication series

NameIFAC Proceedings Volumes
PublisherElsevier
Number3
Volume47
ISSN (Electronic)2405-8963

Conference

Conference19th World Congress of the International Federation of Automatic Control (IFAC 2014)
CountrySouth Africa
CityCape Town
Period24/08/1429/08/14

Keywords

  • best linear approximation (BLA)
  • Wiener-Hammerstein models

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