Initial Undershoot in Discrete-Time Input–Output Hammerstein Systems

This paper considers initial undershoot in the step response of discrete-time, input-output Hammerstein (DIH) systems, which have linear unforced dynamics and nonlinear zero dynamics (ZD). Initial undershoot occurs when the step response of a system moves initially in a direction that is opposite to...

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Main Authors: Hyung Jun Kim, Mohammadreza Kamaldar, Dennis S. Bernstein
Format: Article
Language:English
Published: IEEE 2025-01-01
Series:IEEE Open Journal of Control Systems
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Online Access:https://ieeexplore.ieee.org/document/10824927/
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author Hyung Jun Kim
Mohammadreza Kamaldar
Dennis S. Bernstein
author_facet Hyung Jun Kim
Mohammadreza Kamaldar
Dennis S. Bernstein
author_sort Hyung Jun Kim
collection DOAJ
description This paper considers initial undershoot in the step response of discrete-time, input-output Hammerstein (DIH) systems, which have linear unforced dynamics and nonlinear zero dynamics (ZD). Initial undershoot occurs when the step response of a system moves initially in a direction that is opposite to the direction of the asymptotic response. For DIH systems, the paper investigates the relationship among the existence of initial undershoot, the step height, the height-dependent delay, and the stability of the ZD. For linear, time-invariant systems, the height-dependent delay specializes to the relative degree. The main result of the paper provides conditions under which, for all sufficiently small step heights, initial undershoot in the step response of a DIH system implies instability of the ZD. Several examples of DIH systems are presented to illustrate these results.
format Article
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institution Kabale University
issn 2694-085X
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publishDate 2025-01-01
publisher IEEE
record_format Article
series IEEE Open Journal of Control Systems
spelling doaj-art-409170c282e04125a5f6934fc30773472025-01-30T00:04:44ZengIEEEIEEE Open Journal of Control Systems2694-085X2025-01-014304010.1109/OJCSYS.2025.352598310824927Initial Undershoot in Discrete-Time Input–Output Hammerstein SystemsHyung Jun Kim0https://orcid.org/0009-0006-1837-4280Mohammadreza Kamaldar1https://orcid.org/0000-0002-4774-9794Dennis S. Bernstein2https://orcid.org/0000-0003-0399-3039Department of Aerospace Engineering, University of Michigan, Ann Arbor, MI, USADepartment of Aerospace Engineering, University of Michigan, Ann Arbor, MI, USADepartment of Aerospace Engineering, University of Michigan, Ann Arbor, MI, USAThis paper considers initial undershoot in the step response of discrete-time, input-output Hammerstein (DIH) systems, which have linear unforced dynamics and nonlinear zero dynamics (ZD). Initial undershoot occurs when the step response of a system moves initially in a direction that is opposite to the direction of the asymptotic response. For DIH systems, the paper investigates the relationship among the existence of initial undershoot, the step height, the height-dependent delay, and the stability of the ZD. For linear, time-invariant systems, the height-dependent delay specializes to the relative degree. The main result of the paper provides conditions under which, for all sufficiently small step heights, initial undershoot in the step response of a DIH system implies instability of the ZD. Several examples of DIH systems are presented to illustrate these results.https://ieeexplore.ieee.org/document/10824927/Nonlinear systems and controlstability of nonlinear systemsinitial undershootnonlinear zero dynamicsdiscrete-time input-output Hammerstein system
spellingShingle Hyung Jun Kim
Mohammadreza Kamaldar
Dennis S. Bernstein
Initial Undershoot in Discrete-Time Input–Output Hammerstein Systems
IEEE Open Journal of Control Systems
Nonlinear systems and control
stability of nonlinear systems
initial undershoot
nonlinear zero dynamics
discrete-time input-output Hammerstein system
title Initial Undershoot in Discrete-Time Input–Output Hammerstein Systems
title_full Initial Undershoot in Discrete-Time Input–Output Hammerstein Systems
title_fullStr Initial Undershoot in Discrete-Time Input–Output Hammerstein Systems
title_full_unstemmed Initial Undershoot in Discrete-Time Input–Output Hammerstein Systems
title_short Initial Undershoot in Discrete-Time Input–Output Hammerstein Systems
title_sort initial undershoot in discrete time input x2013 output hammerstein systems
topic Nonlinear systems and control
stability of nonlinear systems
initial undershoot
nonlinear zero dynamics
discrete-time input-output Hammerstein system
url https://ieeexplore.ieee.org/document/10824927/
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AT mohammadrezakamaldar initialundershootindiscretetimeinputx2013outputhammersteinsystems
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