Decoupling P-NARX models using filtered CPD

Jan Decuyper, David Westwick, Kiana Karami, Johan Schoukens

    Research output: Contribution to journalConference articlepeer-review

    Abstract

    Nonlinear Auto-Regressive eXogenous input (NARX) models are a popular class of nonlinear dynamical models. Often a polynomial basis expansion is used to describe the internal multivariate nonlinear mapping (P-NARX). Resorting to fixed basis functions is convenient since it results in a closed form solution of the estimation problem. The drawback, however, is that the predefined basis does not necessarily lead to a sparse representation of the relationship, typically resulting in very large numbers of parameters. So-called decoupling techniques were specifically designed to reduce large multivariate functions. It was found that, often, a more efficient parameterisation can be retrieved by rotating towards a new basis. Characteristic to the decoupled structure is that, expressed in the new basis, the relationship is structured such that only single-input single-output nonlinear functions are required. Classical decoupling techniques are unfit to deal with the case of single-output NARX models. In this work, this limitation is overcome by adopting the filtered CPD decoupling method of Decuyper et al. (2021b). The approach is illustrated on data from the Sliverbox benchmark: measurement data from an electronic circuit implementation of a forced Duffing oscillator.

    Original languageEnglish (US)
    Pages (from-to)661-666
    Number of pages6
    JournalIFAC-PapersOnLine
    Volume54
    Issue number7
    DOIs
    StatePublished - Jul 1 2021
    Event19th IFAC Symposium on System Identification, SYSID 2021 - Padova, Italy
    Duration: Jul 13 2021Jul 16 2021

    All Science Journal Classification (ASJC) codes

    • Control and Systems Engineering

    Cite this