Improvement of the Asymptotic Properties of Zero Dynamics for Sampled-Data Systems in the Case of a Time Delay

It is well known that the existence of unstable zero dynamics is recognized as a major barrier in many control systems, and deeply limits the achievable control performance. When a continuous-time system with relative degree greater than or equal to three is discretized using a zero-order hold (ZOH)...

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Main Authors: Cheng Zeng, Shan Liang, Jiaqi Zhong, Yingying Su
Format: Article
Language:English
Published: Wiley 2014-01-01
Series:Abstract and Applied Analysis
Online Access:http://dx.doi.org/10.1155/2014/817534
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author Cheng Zeng
Shan Liang
Jiaqi Zhong
Yingying Su
author_facet Cheng Zeng
Shan Liang
Jiaqi Zhong
Yingying Su
author_sort Cheng Zeng
collection DOAJ
description It is well known that the existence of unstable zero dynamics is recognized as a major barrier in many control systems, and deeply limits the achievable control performance. When a continuous-time system with relative degree greater than or equal to three is discretized using a zero-order hold (ZOH), at least one of the zero dynamics of the resulting sampled-data model is obviously unstable for sufficiently small sampling periods, irrespective of whether they involve time delay or not. Thus, attention is here focused on continuous-time systems with time delay and relative degree two. This paper analyzes the asymptotic behavior of zero dynamics for the sampled-data models corresponding to the continuous-time systems mentioned above, and further gives an approximate expression of the zero dynamics in the form of a power series expansion up to the third order term of sampling period. Meanwhile, the stability of the zero dynamics is discussed for sufficiently small sampling periods and a new stability condition is also derived. The ideas presented here generalize well-known results from the delay-free control system to time-delay case.
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institution Kabale University
issn 1085-3375
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language English
publishDate 2014-01-01
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series Abstract and Applied Analysis
spelling doaj-art-314f9e106df1464d9fd89af6111305a22025-02-03T06:12:34ZengWileyAbstract and Applied Analysis1085-33751687-04092014-01-01201410.1155/2014/817534817534Improvement of the Asymptotic Properties of Zero Dynamics for Sampled-Data Systems in the Case of a Time DelayCheng Zeng0Shan Liang1Jiaqi Zhong2Yingying Su3College of Automation, Chongqing University, Chongqing 400044, ChinaCollege of Automation, Chongqing University, Chongqing 400044, ChinaCollege of Automation, Chongqing University, Chongqing 400044, ChinaCollege of Automation, Chongqing University, Chongqing 400044, ChinaIt is well known that the existence of unstable zero dynamics is recognized as a major barrier in many control systems, and deeply limits the achievable control performance. When a continuous-time system with relative degree greater than or equal to three is discretized using a zero-order hold (ZOH), at least one of the zero dynamics of the resulting sampled-data model is obviously unstable for sufficiently small sampling periods, irrespective of whether they involve time delay or not. Thus, attention is here focused on continuous-time systems with time delay and relative degree two. This paper analyzes the asymptotic behavior of zero dynamics for the sampled-data models corresponding to the continuous-time systems mentioned above, and further gives an approximate expression of the zero dynamics in the form of a power series expansion up to the third order term of sampling period. Meanwhile, the stability of the zero dynamics is discussed for sufficiently small sampling periods and a new stability condition is also derived. The ideas presented here generalize well-known results from the delay-free control system to time-delay case.http://dx.doi.org/10.1155/2014/817534
spellingShingle Cheng Zeng
Shan Liang
Jiaqi Zhong
Yingying Su
Improvement of the Asymptotic Properties of Zero Dynamics for Sampled-Data Systems in the Case of a Time Delay
Abstract and Applied Analysis
title Improvement of the Asymptotic Properties of Zero Dynamics for Sampled-Data Systems in the Case of a Time Delay
title_full Improvement of the Asymptotic Properties of Zero Dynamics for Sampled-Data Systems in the Case of a Time Delay
title_fullStr Improvement of the Asymptotic Properties of Zero Dynamics for Sampled-Data Systems in the Case of a Time Delay
title_full_unstemmed Improvement of the Asymptotic Properties of Zero Dynamics for Sampled-Data Systems in the Case of a Time Delay
title_short Improvement of the Asymptotic Properties of Zero Dynamics for Sampled-Data Systems in the Case of a Time Delay
title_sort improvement of the asymptotic properties of zero dynamics for sampled data systems in the case of a time delay
url http://dx.doi.org/10.1155/2014/817534
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AT jiaqizhong improvementoftheasymptoticpropertiesofzerodynamicsforsampleddatasystemsinthecaseofatimedelay
AT yingyingsu improvementoftheasymptoticpropertiesofzerodynamicsforsampleddatasystemsinthecaseofatimedelay