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INTEGRAL INPUT-TO-OUTPUT STABILITY ANALYSIS FOR NONLINEAR SYSTEMS WITH TIME DELAYS
Title
INTEGRAL INPUT-TO-OUTPUT STABILITY ANALYSIS FOR NONLINEAR SYSTEMS WITH TIME DELAYS.
Creator
Nawarathna, R. H. Harsha, Wang, Yuan, Florida Atlantic University, Department of Mathematical Sciences, Charles E. Schmidt College of Science
Abstract/Description
One of the central issues in stability analysis for control systems is how robust a stability property is when external disturbances are presented. This is even more critical when a system is affected by time delay. Systems affected by time delays are ubiquitous in applications. Time delays add more challenges to the task of stability analysis, mainly due to the fact that the state space of a delay system is not a finite-dimensional Euclidean space anymore, but rather an infinite dimensional...
Show moreOne of the central issues in stability analysis for control systems is how robust a stability property is when external disturbances are presented. This is even more critical when a system is affected by time delay. Systems affected by time delays are ubiquitous in applications. Time delays add more challenges to the task of stability analysis, mainly due to the fact that the state space of a delay system is not a finite-dimensional Euclidean space anymore, but rather an infinite dimensional space of continuous functions defined on the delay interval. In this work, we investigate robust output stability properties for nonlinear systems affected by time delays and external disturbances. Frequently in applications, the requirement of stability properties imposed on the full set of state variables can be too strenuous or even unrealistic. This motivates one to consider robust output stability properties which are related to partial stability analysis in the classic literature. We start by formulating several notions on integral input-to-output stability and illustrate how these notions are related. We then continue to develop Lyapunov-Krasovskii type of results for such stability properties. As in the other context of Lyapunov stability analysis such as global asymptotic stability and input-to-state stability, a Lyapunov-Krasovskii functional is required to have a decay rate proportional to the magnitudes of the state variables or output variables on the whole delayed interval. This is a difficult feature when trying to construct a Lyapunov-Krasovskii functional. For this issue, we turn our efforts to Lyapunov-Krasovskii functional with a decay rate depending only on the current values of state variables or output variables. Our results lead to a type of Lyapunov-Krasovskii functionals that are more flexible regarding the decay rate, thereby leading to more efficient results for applications.
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Date Issued
2023
PURL
http://purl.flvc.org/fau/fd/FA00014267
Subject Headings
Nonlinear systems, Time delay systems
Format
Document (PDF)
Remarks on stability analysis for delayed systems with applications
Title
Remarks on stability analysis for delayed systems with applications.
Creator
Tiwari, Shanaz, Wang, Yuan, Graduate College
Date Issued
2011-04-08
PURL
http://purl.flvc.org/fcla/dt/3164800
Subject Headings
Nonlinear control theory, Lyapunov functions, Time delay systems
Format
Document (PDF)
Output Stability Analysis for Nonlinear Systems with Time Delays
Title
Output Stability Analysis for Nonlinear Systems with Time Delays.
Creator
Gallolu Kankanamalage, Hasala Senpathy, Wang, Yuan, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Mathematical Sciences
Abstract/Description
Systems with time delays have a broad range of applications not only in control systems but also in many other disciplines such as mathematical biology, financial economics, etc. The time delays cause more complex behaviours of the systems. It requires more sophisticated analysis due to the infinite dimensional structure of the space spaces. In this thesis we investigate stability properties associated with output functions of delay systems. Our primary target is the equivalent Lyapunov...
Show moreSystems with time delays have a broad range of applications not only in control systems but also in many other disciplines such as mathematical biology, financial economics, etc. The time delays cause more complex behaviours of the systems. It requires more sophisticated analysis due to the infinite dimensional structure of the space spaces. In this thesis we investigate stability properties associated with output functions of delay systems. Our primary target is the equivalent Lyapunov characterization of input-tooutput stability (ios). A main approach used in this work is the Lyapuno Krasovskii functional method. The Lyapunov characterization of the so called output-Lagrange stability is technically the backbone of this work, as it induces a Lyapunov description for all the other output stability properties, in particular for ios. In the study, we consider two types of output functions. The first type is defined in between Banach spaces, whereas the second type is defined between Euclidean spaces. The Lyapunov characterization for the first type of output maps provides equivalence between the stability properties and the existence of the Lyapunov-Krasovskii functionals. On the other hand, as a special case of the first type, the second type output renders flexible Lyapunov descriptions that are more efficient in applications. In the special case when the output variables represent the complete collection of the state variables, our Lyapunov work lead to Lyapunov characterizations of iss, complementing the current iss theory with some novel results. We also aim at understanding how output stability are affected by the initial data and the external signals. Since the output variables are in general not a full collection of the state variables, the overshoots and decay properties may be affected in different ways by the initial data of either the state variables or just only the output variables. Accordingly, there are different ways of defining notions on output stability, making them mathematically precisely. After presenting the definitions, we explore the connections of these notions. Understanding the relation among the notions is not only mathematically necessary, it also provides guidelines in system control and design.
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Date Issued
2017
PURL
http://purl.flvc.org/fau/fd/FA00004935, http://purl.flvc.org/fau/fd/FA00004935
Subject Headings
Nonlinear systems., Time delay systems., Multiagent systems., Adaptive control systems., Chaotic behavior in systems.
Format
Document (PDF)
study of Internet-based control of processes
Title
A study of Internet-based control of processes.
Creator
Popescu, Cristian., Florida Atlantic University, Zhuang, Hanqi, Wang, Yuan, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description
In certain applications, one needs to control physical plants that operate in hazardous conditions. In such situations, it is necessary to acquire access to the controller from a different (remote) location through data communication networks, in order to interconnect the remote location and the controller. The use of such network linking between the plant and the controller may introduce network delays, which would affect adversely the performance of the process control. The main theoretical...
Show moreIn certain applications, one needs to control physical plants that operate in hazardous conditions. In such situations, it is necessary to acquire access to the controller from a different (remote) location through data communication networks, in order to interconnect the remote location and the controller. The use of such network linking between the plant and the controller may introduce network delays, which would affect adversely the performance of the process control. The main theoretical contribution of this thesis is to answer the following question: How large can a network delay be tolerated such that the delayed closed-loop system is locally asymptotically stable? An explicit time-independent bound for the delay is derived. In addition, various practical realizations for the remote control tasks are presented, utilizing a set of predefined classes for serial communication, data-acquisition modules and stream-based sockets. Due to the presence of a network, implementing an efficient control scheme is a not trivial problem. Hence, two practical frameworks for Internet-based control are illustrated in this thesis. Related implementation issues are addressed in detail. Examples and case studies are provided to demonstrate the effectiveness of the proposal approach.
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Date Issued
2003
PURL
http://purl.flvc.org/fcla/dt/13073
Subject Headings
Time delay systems, Process control, Computer networks--Remote access, World Wide Web
Format
Document (PDF)