Exact and Inexact Lifting Transformations of Nonlinear Dynamical Systems: Transfer Functions, Equivalence, and Complexity Reduction

In this work, we deal with the problem of approximating and equivalently formulating generic nonlinear systems by means of specific classes thereof. Bilinear and quadratic-bilinear systems accomplish precisely this goal. Hence, by means of exact and inexact lifting transformations, we are able to re...

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Main Author: Ion Victor Gosea
Format: Article
Language:English
Published: MDPI AG 2022-02-01
Series:Applied Sciences
Subjects:
Online Access:https://www.mdpi.com/2076-3417/12/5/2333
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author Ion Victor Gosea
author_facet Ion Victor Gosea
author_sort Ion Victor Gosea
collection DOAJ
description In this work, we deal with the problem of approximating and equivalently formulating generic nonlinear systems by means of specific classes thereof. Bilinear and quadratic-bilinear systems accomplish precisely this goal. Hence, by means of exact and inexact lifting transformations, we are able to reformulate the original nonlinear dynamics into a different, more simplified format. Additionally, we study the problem of complexity/model reduction of large-scale lifted models of nonlinear systems from data. The method under consideration is the Loewner framework, an established data-driven approach that requires samples of input–output mappings. The latter are known as generalized transfer functions, which are appropriately defined for both bilinear and quadratic-bilinear systems. We show connections between these mappings as well as between the matrices of reduced-order models. Finally, we illustrate the theoretical discussion with two numerical examples.
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spelling doaj.art-9d6452942b9b470c9edf30271a46ecfc2023-11-23T22:39:08ZengMDPI AGApplied Sciences2076-34172022-02-01125233310.3390/app12052333Exact and Inexact Lifting Transformations of Nonlinear Dynamical Systems: Transfer Functions, Equivalence, and Complexity ReductionIon Victor Gosea0Data-Driven System Reduction and Identification Group, Max Planck Institute for Dynamics of Complex Technical Systems, Sandtorstrasse 1, 39114 Magdeburg, GermanyIn this work, we deal with the problem of approximating and equivalently formulating generic nonlinear systems by means of specific classes thereof. Bilinear and quadratic-bilinear systems accomplish precisely this goal. Hence, by means of exact and inexact lifting transformations, we are able to reformulate the original nonlinear dynamics into a different, more simplified format. Additionally, we study the problem of complexity/model reduction of large-scale lifted models of nonlinear systems from data. The method under consideration is the Loewner framework, an established data-driven approach that requires samples of input–output mappings. The latter are known as generalized transfer functions, which are appropriately defined for both bilinear and quadratic-bilinear systems. We show connections between these mappings as well as between the matrices of reduced-order models. Finally, we illustrate the theoretical discussion with two numerical examples.https://www.mdpi.com/2076-3417/12/5/2333nonlinear systemscomplexity model reductiondata-driven methodsbilinear quadratic structuretransfer functionslifting transformations
spellingShingle Ion Victor Gosea
Exact and Inexact Lifting Transformations of Nonlinear Dynamical Systems: Transfer Functions, Equivalence, and Complexity Reduction
Applied Sciences
nonlinear systems
complexity model reduction
data-driven methods
bilinear quadratic structure
transfer functions
lifting transformations
title Exact and Inexact Lifting Transformations of Nonlinear Dynamical Systems: Transfer Functions, Equivalence, and Complexity Reduction
title_full Exact and Inexact Lifting Transformations of Nonlinear Dynamical Systems: Transfer Functions, Equivalence, and Complexity Reduction
title_fullStr Exact and Inexact Lifting Transformations of Nonlinear Dynamical Systems: Transfer Functions, Equivalence, and Complexity Reduction
title_full_unstemmed Exact and Inexact Lifting Transformations of Nonlinear Dynamical Systems: Transfer Functions, Equivalence, and Complexity Reduction
title_short Exact and Inexact Lifting Transformations of Nonlinear Dynamical Systems: Transfer Functions, Equivalence, and Complexity Reduction
title_sort exact and inexact lifting transformations of nonlinear dynamical systems transfer functions equivalence and complexity reduction
topic nonlinear systems
complexity model reduction
data-driven methods
bilinear quadratic structure
transfer functions
lifting transformations
url https://www.mdpi.com/2076-3417/12/5/2333
work_keys_str_mv AT ionvictorgosea exactandinexactliftingtransformationsofnonlineardynamicalsystemstransferfunctionsequivalenceandcomplexityreduction