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SAMI ELMADSSIA

Ecole Nationale d'Ingénieurs de Tunis (ENIT), Lara, Post-Doc

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Senior member IEEE. Received my engineering diploma in electrical engineering in 2004 , my master’s diploma in automatic treatment of signals in 2005 and in 2011, I
received my PhD. All from the National School of Engineers of Tunis (ENIT), Tunisia. Presently, I am a researcher at SYS'COM Lab of ENIT. My research interests include stability and control of linear and nonlinear time-delay systems and applications to process control problems game theory, AI and IoT.

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University of Missouri - St. Louis

University of California, Santa Barbara

Harvard University

Fortis Escorts Heart Institute

Hacettepe University

Asep K Supriatna

University of Padjadjaran (UNPAD)

The University of Sheffield

Evangelos Papadopoulos

National Technical University of Athens

Armando Marques-Guedes

UNL - New University of Lisbon

Indiana University

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Books by SAMI ELMADSSIA

New Stability Conditions for a Class of Nonlinear Discrete-Time Systems with Time-Varying Delay

Mathematics 2020, 8, 1531; , 2020

In this paper, the stability problem of discrete time delay systems is investigated. The class o... more In this paper, the stability problem of discrete time delay systems is investigated. The class of systems under consideration is represented by delayed difference equations and models nonlinear discrete time systems with time varying delay. It is transformed into an arrow from matrix representation which allows the use of aggregation techniques and M-matrix properties to determine novel sufﬁcient stability conditions. The originalities of our ﬁndings are shown in their explicit representation, using system’s parameters, as well as in their easiness to be employed. The obtained results demonstrate also that checking stability of nonlinear discrete time systems with time varying delay can be reduced to an M-matrix test. Next, it is shown how to use our method in designing a state feedback controller that stabilizes a discrete time Lure system with time varying delay and sector bounded nonlinearity. Finally, several examples are provided to show the effectiveness of the introduced technique.

Stability Conditions for a Class of Nonlinear Systems with Delay

intechopen., 2018

This chapter presents an extension and offers a more comprehensive overview of our previous paper... more This chapter presents an extension and offers a more comprehensive overview of our previous paper entitled "Stability conditions for a class of nonlinear time delay systems" published in "Nonlinear Dynamics and Systems Theory" journal. We first introduce a more complete approach of the nonlinear system stability for the single delay case. Then, we show the application of the obtained results to delayed Lur'e Postnikov systems. A state space representation of the class of system under consideration is used and a new transformation is carried out to represent the system, with delay, by an arrow form matrix. Taking advantage of this representation and applying the Kotelyanski lemma in combination with properties of M-matrices, some new sufficient stability conditions are determined. Finally, illustrative example is provided to show the easiness of using the given stability conditions.

Nouvelles Approches de Stabilité des Systèmes Dynamiques à Retards: Stabilité et Stabilisation

Les travaux présentés dans ce livre concernent les systèmes linéaires et non linéaires décrits pa... more Les travaux présentés dans ce livre concernent les systèmes linéaires et non linéaires décrits par des équations différentielles à états retardés. Ils utilisent des fonctions de Lyapunov radialement non bornées et des techniques d'agrégation basées sur l'utilisation des normes vectorielles. La contribution principale de ce travail réside dans la proposition d'une méthode algébrique de détermination de modèles particuliers associés aux systèmes à retard(s) explicitant les spécificités dynamiques et structurelles de ceux-ci, adaptées aux méthodes d'études retenues. Nous présentons, dans ce sens, des nouvelles conditions de stabilité ou de stabilisation dépendantes ou non de la taille du retard et pouvant être facilement implémentées en pratique. Toutes les conditions présentées sont de dimension finie, bien que les systèmes analysés sont de dimension infinie. Les aspects robustesse et atténuation de perturbations sont également considérés.

Papers by SAMI ELMADSSIA

A Comprehensive Survey on Game Theory Applications in Cyber-Physical System Security: Attack Models, Security Analyses, and Machine Learning Classifications

IEEE Access , 2024

The increasing integration of cyber-physical systems (CPS) in critical infrastructures has height... more The increasing integration of cyber-physical systems (CPS) in critical infrastructures has heightened the importance of ensuring their security against various cyber threats. Game theory has emerged as a powerful analytical tool to model and analyze the strategic interactions between attackers and defenders in CPS. This survey provides a comprehensive review of the state-of-the-art research on the application of game theory in the security of CPS, with a specific focus on attack models and security analysis. We employ machine learning algorithms to classify existing research papers based on the attack target and the types of attacks they address. Our classification reveals significant trends and gaps in the current literature, offering insights into the effectiveness of different game-theoretic approaches and the prevalence of various attack models. By synthesizing the findings from over 800 research papers, we highlight the strengths and limitations of existing methodologies and propose directions for future research. This survey aims to serve as a valuable resource for researchers and practitioners seeking to enhance the security of CPS through game-theoretic frameworks and machine learning techniques.

Influence of Interference and Sampling Period in the Performance of Networked Control Systems

New stability and stabilization conditions for a class TSK fuzzy systems with time delays

Nucleation and Atmospheric Aerosols, 2022

New delay-dependent stability conditions for linear systems with delay

Systems Science & Control Engineering, Dec 1, 2013

Distributed consensus control for multi‐agent systems using terminal sliding mode and Chebyshev neural networks

International Journal of Robust and Nonlinear Control, 2011

SUMMARYThis paper investigates the problem of consensus tracking control for second‐order multi‐a... more SUMMARYThis paper investigates the problem of consensus tracking control for second‐order multi‐agent systems in the presence of uncertain dynamics and bounded external disturbances. The communication ﬂow among neighbor agents is described by an undirected connected graph. A fast terminal sliding manifold based on lumped state errors that include absolute and relative state errors is proposed, and then a distributed finite‐time consensus tracking controller is developed by using terminal sliding mode and Chebyshev neural networks. In the proposed control scheme, Chebyshev neural networks are used as universal approximators to learn unknown nonlinear functions in the agent dynamics online, and a robust control term using the hyperbolic tangent function is applied to counteract neural‐network approximation errors and external disturbances, which makes the proposed controller be continuous and hence chattering‐free. Meanwhile, a smooth projection algorithm is employed to guarantee that...

Analytical Stability Conditions on Interconnected Nonlinear Systems With Delays

IEEE Access, 2021

This paper is concerned with stability of interconnected systems with time delays. We develop a s... more This paper is concerned with stability of interconnected systems with time delays. We develop a self-contained approach to stability analysis for linear and nonlinear systems in a unified framework. New lemmas are established on matrix properties and used as the key to make negativity of the derivative of the Lyapunov function. The scalar and simple analytical stability conditions are given. Unlike the majority of the literature on stability of delay systems, no matrix equations/inequalities are involved in our conditions, which is true even for large-scale systems and nonlinear subsystems with delayed interconnections. They are applicable to the more general nonlinear, time-varying, and/or interconnected systems than the relevant results reported in the literature. The examples are presented for illustration of the new results.

Stabilizing PID Controllers for a Class of Time Delay Systems

by Karim Saadaoui and SAMI ELMADSSIA

PID Controller Design Approaches - Theory, Tuning and Application to Frontier Areas, 2012

percent overshoot, settling time, rise time and integral square error, were minimized. Applicatio... more

New Stability Conditions for Neutral and Retarded Time Delay Systems

ABSTRACT In this paper, new stability conditions for time delay system are proposed. They are bas... more ABSTRACT In this paper, new stability conditions for time delay system are proposed. They are based on the use of the aggregation techniques and the choice of a state representation as Benrejeb arrow form characteristic matrix. Neutral type and retarded type time delay systems are considered. Application cases are treated to illustrate the implementation of the proposed approach.

New stability conditions for nonlinear time delay systems

2013 International Conference on Control, Decision and Information Technologies (CoDIT), 2013

ABSTRACT In this paper a new practical stability conditions for delayed Lur&amp;#39;e Postnik... more ABSTRACT In this paper a new practical stability conditions for delayed Lur&amp;#39;e Postnikov system are proposed. The study use a specific form state space description, named, Benrejeb characteristic arrow matrix. An illustrative example is presented to show the efficiency of proposed method.

New delay-independent stability conditions for time delay systems

2011 International Conference on Communications, Computing and Control Applications (CCCA), 2011

ABSTRACT In this paper, new stability conditions for time delay system are proposed. They are bas... more ABSTRACT In this paper, new stability conditions for time delay system are proposed. They are based on the use of the aggregation techniques and the choice of a state representation as Benrejeb arrow form characteristic matrix. Application cases are treated to illustrate the implementation of the proposed approach.

Stability Conditions for a Class of Nonlinear Systems with Delay

Nonlinear Systems - Modeling, Estimation, and Stability, 2018

This chapter presents an extension and offers a more comprehensive overview of our previous paper... more This chapter presents an extension and offers a more comprehensive overview of our previous paper entitled "Stability conditions for a class of nonlinear time delay systems" published in "Nonlinear Dynamics and Systems Theory" journal. We first introduce a more complete approach of the nonlinear system stability for the single delay case. Then, we show the application of the obtained results to delayed Lur'e Postnikov systems. A state space representation of the class of system under consideration is used and a new transformation is carried out to represent the system, with delay, by an arrow form matrix. Taking advantage of this representation and applying the Kotelyanski lemma in combination with properties of M-matrices, some new sufficient stability conditions are determined. Finally, illustrative example is provided to show the easiness of using the given stability conditions.

Stability Conditions for a Class of Nonlinear Time Delay Systems

In this paper, stability analysis for a class of nonlinear time delay system is done. A state spa... more In this paper, stability analysis for a class of nonlinear time delay system is done. A state space representation of the class of system under consideration is used and a transformation is carried out to represent the system by an arrow form matrix. Taking advantage of this representation and applying the Kotelyanski lemma in combination with properties of M-matrices, some new sufficient stability conditions are determined. An illustrative example is presented to show the effectiveness of the proposed approach.

Certificate of Attendance

Analytical Stability Conditions on Interconnected Nonlinear Systems With Delays

IEEE Access, 2021

This paper is concerned with stability of interconnected systems with time delays. We develop a s... more This paper is concerned with stability of interconnected systems with time delays. We develop a self-contained approach to stability analysis for linear and nonlinear systems in a unified framework. New lemmas are established on matrix properties and used as the key to make negativity of the derivative of the Lyapunov function. The scalar and simple analytical stability conditions are given. Unlike the majority of the literature on stability of delay systems, no matrix equations/inequalities are involved in our conditions, which is true even for large-scale systems and nonlinear subsystems with delayed interconnections. They are applicable to the more general nonlinear, time-varying, and/or interconnected systems than the relevant results reported in the literature. The examples are presented for illustration of the new results.

Taylor & Francis Online :: New delay-dependent stability

On the stabilization of a TCP/AQM systems with time delay by the joint use of the τ-decomposition and the D-decomposition methods

2017 International Conference on Internet of Things, Embedded Systems and Communications (IINTEC), 2017

The work presented in this paper proposes a new method of stabilization of a second order system ... more The work presented in this paper proposes a new method of stabilization of a second order system by a delayed positive feedback. This method is based on the root locus approach. The τ-decomposition and D-decomposition methods are used to determine regions in the parameters' space that ensure stability of the closed-loop system. The use of this method for stabilization of a TCP/AQM systems with time delay is successfully applied. An illustrative example is given to show the application of our method.

New stability conditions for class of nonlinear discrete-time systems with time-varying delay

The problem of stability analysis for a class of nonlinear discrete time systems with time varyin... more The problem of stability analysis for a class of nonlinear discrete time systems with time varying delay is studied in this work. Such systems are modeled by delayed difference equations. Subsequently, this system is transformed into an arrow form matrix representation. Using M-matrix properties, novel sufficient stability conditions are determined. It is shown how to use our method to design a state feedback controller that stabilizes a discrete time Lure system with time varying delay and sector bounded nonlinearity. The originalities of our findings are shown in their explicit representation, using system’s parameters, as well as in their easiness to be employed. The obtained results demonstrate also that checking stability of a nonlinear discrete time systems with time varying delay can be reduced to an M-matrix test. Several examples are provided to show the effectiveness of the introduced technique.

New Stability Conditions for a Class of Nonlinear Discrete-Time Systems with Time-Varying Delay

Mathematics 2020, 8, 1531; , 2020

In this paper, the stability problem of discrete time delay systems is investigated. The class o... more In this paper, the stability problem of discrete time delay systems is investigated. The class of systems under consideration is represented by delayed difference equations and models nonlinear discrete time systems with time varying delay. It is transformed into an arrow from matrix representation which allows the use of aggregation techniques and M-matrix properties to determine novel sufﬁcient stability conditions. The originalities of our ﬁndings are shown in their explicit representation, using system’s parameters, as well as in their easiness to be employed. The obtained results demonstrate also that checking stability of nonlinear discrete time systems with time varying delay can be reduced to an M-matrix test. Next, it is shown how to use our method in designing a state feedback controller that stabilizes a discrete time Lure system with time varying delay and sector bounded nonlinearity. Finally, several examples are provided to show the effectiveness of the introduced technique.

Stability Conditions for a Class of Nonlinear Systems with Delay

intechopen., 2018

This chapter presents an extension and offers a more comprehensive overview of our previous paper... more This chapter presents an extension and offers a more comprehensive overview of our previous paper entitled "Stability conditions for a class of nonlinear time delay systems" published in "Nonlinear Dynamics and Systems Theory" journal. We first introduce a more complete approach of the nonlinear system stability for the single delay case. Then, we show the application of the obtained results to delayed Lur'e Postnikov systems. A state space representation of the class of system under consideration is used and a new transformation is carried out to represent the system, with delay, by an arrow form matrix. Taking advantage of this representation and applying the Kotelyanski lemma in combination with properties of M-matrices, some new sufficient stability conditions are determined. Finally, illustrative example is provided to show the easiness of using the given stability conditions.

Nouvelles Approches de Stabilité des Systèmes Dynamiques à Retards: Stabilité et Stabilisation

Les travaux présentés dans ce livre concernent les systèmes linéaires et non linéaires décrits pa... more Les travaux présentés dans ce livre concernent les systèmes linéaires et non linéaires décrits par des équations différentielles à états retardés. Ils utilisent des fonctions de Lyapunov radialement non bornées et des techniques d'agrégation basées sur l'utilisation des normes vectorielles. La contribution principale de ce travail réside dans la proposition d'une méthode algébrique de détermination de modèles particuliers associés aux systèmes à retard(s) explicitant les spécificités dynamiques et structurelles de ceux-ci, adaptées aux méthodes d'études retenues. Nous présentons, dans ce sens, des nouvelles conditions de stabilité ou de stabilisation dépendantes ou non de la taille du retard et pouvant être facilement implémentées en pratique. Toutes les conditions présentées sont de dimension finie, bien que les systèmes analysés sont de dimension infinie. Les aspects robustesse et atténuation de perturbations sont également considérés.

A Comprehensive Survey on Game Theory Applications in Cyber-Physical System Security: Attack Models, Security Analyses, and Machine Learning Classifications

IEEE Access , 2024

The increasing integration of cyber-physical systems (CPS) in critical infrastructures has height... more The increasing integration of cyber-physical systems (CPS) in critical infrastructures has heightened the importance of ensuring their security against various cyber threats. Game theory has emerged as a powerful analytical tool to model and analyze the strategic interactions between attackers and defenders in CPS. This survey provides a comprehensive review of the state-of-the-art research on the application of game theory in the security of CPS, with a specific focus on attack models and security analysis. We employ machine learning algorithms to classify existing research papers based on the attack target and the types of attacks they address. Our classification reveals significant trends and gaps in the current literature, offering insights into the effectiveness of different game-theoretic approaches and the prevalence of various attack models. By synthesizing the findings from over 800 research papers, we highlight the strengths and limitations of existing methodologies and propose directions for future research. This survey aims to serve as a valuable resource for researchers and practitioners seeking to enhance the security of CPS through game-theoretic frameworks and machine learning techniques.

Influence of Interference and Sampling Period in the Performance of Networked Control Systems

New stability and stabilization conditions for a class TSK fuzzy systems with time delays

Nucleation and Atmospheric Aerosols, 2022

New delay-dependent stability conditions for linear systems with delay

Systems Science & Control Engineering, Dec 1, 2013

Distributed consensus control for multi‐agent systems using terminal sliding mode and Chebyshev neural networks

International Journal of Robust and Nonlinear Control, 2011

SUMMARYThis paper investigates the problem of consensus tracking control for second‐order multi‐a... more SUMMARYThis paper investigates the problem of consensus tracking control for second‐order multi‐agent systems in the presence of uncertain dynamics and bounded external disturbances. The communication ﬂow among neighbor agents is described by an undirected connected graph. A fast terminal sliding manifold based on lumped state errors that include absolute and relative state errors is proposed, and then a distributed finite‐time consensus tracking controller is developed by using terminal sliding mode and Chebyshev neural networks. In the proposed control scheme, Chebyshev neural networks are used as universal approximators to learn unknown nonlinear functions in the agent dynamics online, and a robust control term using the hyperbolic tangent function is applied to counteract neural‐network approximation errors and external disturbances, which makes the proposed controller be continuous and hence chattering‐free. Meanwhile, a smooth projection algorithm is employed to guarantee that...

Analytical Stability Conditions on Interconnected Nonlinear Systems With Delays

IEEE Access, 2021

This paper is concerned with stability of interconnected systems with time delays. We develop a s... more This paper is concerned with stability of interconnected systems with time delays. We develop a self-contained approach to stability analysis for linear and nonlinear systems in a unified framework. New lemmas are established on matrix properties and used as the key to make negativity of the derivative of the Lyapunov function. The scalar and simple analytical stability conditions are given. Unlike the majority of the literature on stability of delay systems, no matrix equations/inequalities are involved in our conditions, which is true even for large-scale systems and nonlinear subsystems with delayed interconnections. They are applicable to the more general nonlinear, time-varying, and/or interconnected systems than the relevant results reported in the literature. The examples are presented for illustration of the new results.

Stabilizing PID Controllers for a Class of Time Delay Systems

by Karim Saadaoui and SAMI ELMADSSIA

PID Controller Design Approaches - Theory, Tuning and Application to Frontier Areas, 2012

percent overshoot, settling time, rise time and integral square error, were minimized. Applicatio... more

New Stability Conditions for Neutral and Retarded Time Delay Systems

ABSTRACT In this paper, new stability conditions for time delay system are proposed. They are bas... more ABSTRACT In this paper, new stability conditions for time delay system are proposed. They are based on the use of the aggregation techniques and the choice of a state representation as Benrejeb arrow form characteristic matrix. Neutral type and retarded type time delay systems are considered. Application cases are treated to illustrate the implementation of the proposed approach.

New stability conditions for nonlinear time delay systems

2013 International Conference on Control, Decision and Information Technologies (CoDIT), 2013

ABSTRACT In this paper a new practical stability conditions for delayed Lur&amp;#39;e Postnik... more ABSTRACT In this paper a new practical stability conditions for delayed Lur&amp;#39;e Postnikov system are proposed. The study use a specific form state space description, named, Benrejeb characteristic arrow matrix. An illustrative example is presented to show the efficiency of proposed method.

New delay-independent stability conditions for time delay systems

2011 International Conference on Communications, Computing and Control Applications (CCCA), 2011

ABSTRACT In this paper, new stability conditions for time delay system are proposed. They are bas... more ABSTRACT In this paper, new stability conditions for time delay system are proposed. They are based on the use of the aggregation techniques and the choice of a state representation as Benrejeb arrow form characteristic matrix. Application cases are treated to illustrate the implementation of the proposed approach.

Stability Conditions for a Class of Nonlinear Systems with Delay

Nonlinear Systems - Modeling, Estimation, and Stability, 2018

This chapter presents an extension and offers a more comprehensive overview of our previous paper... more This chapter presents an extension and offers a more comprehensive overview of our previous paper entitled "Stability conditions for a class of nonlinear time delay systems" published in "Nonlinear Dynamics and Systems Theory" journal. We first introduce a more complete approach of the nonlinear system stability for the single delay case. Then, we show the application of the obtained results to delayed Lur'e Postnikov systems. A state space representation of the class of system under consideration is used and a new transformation is carried out to represent the system, with delay, by an arrow form matrix. Taking advantage of this representation and applying the Kotelyanski lemma in combination with properties of M-matrices, some new sufficient stability conditions are determined. Finally, illustrative example is provided to show the easiness of using the given stability conditions.

Stability Conditions for a Class of Nonlinear Time Delay Systems

In this paper, stability analysis for a class of nonlinear time delay system is done. A state spa... more In this paper, stability analysis for a class of nonlinear time delay system is done. A state space representation of the class of system under consideration is used and a transformation is carried out to represent the system by an arrow form matrix. Taking advantage of this representation and applying the Kotelyanski lemma in combination with properties of M-matrices, some new sufficient stability conditions are determined. An illustrative example is presented to show the effectiveness of the proposed approach.

Certificate of Attendance

Analytical Stability Conditions on Interconnected Nonlinear Systems With Delays

IEEE Access, 2021

This paper is concerned with stability of interconnected systems with time delays. We develop a s... more This paper is concerned with stability of interconnected systems with time delays. We develop a self-contained approach to stability analysis for linear and nonlinear systems in a unified framework. New lemmas are established on matrix properties and used as the key to make negativity of the derivative of the Lyapunov function. The scalar and simple analytical stability conditions are given. Unlike the majority of the literature on stability of delay systems, no matrix equations/inequalities are involved in our conditions, which is true even for large-scale systems and nonlinear subsystems with delayed interconnections. They are applicable to the more general nonlinear, time-varying, and/or interconnected systems than the relevant results reported in the literature. The examples are presented for illustration of the new results.

Taylor & Francis Online :: New delay-dependent stability

On the stabilization of a TCP/AQM systems with time delay by the joint use of the τ-decomposition and the D-decomposition methods

2017 International Conference on Internet of Things, Embedded Systems and Communications (IINTEC), 2017

The work presented in this paper proposes a new method of stabilization of a second order system ... more The work presented in this paper proposes a new method of stabilization of a second order system by a delayed positive feedback. This method is based on the root locus approach. The τ-decomposition and D-decomposition methods are used to determine regions in the parameters' space that ensure stability of the closed-loop system. The use of this method for stabilization of a TCP/AQM systems with time delay is successfully applied. An illustrative example is given to show the application of our method.

New stability conditions for class of nonlinear discrete-time systems with time-varying delay

The problem of stability analysis for a class of nonlinear discrete time systems with time varyin... more The problem of stability analysis for a class of nonlinear discrete time systems with time varying delay is studied in this work. Such systems are modeled by delayed difference equations. Subsequently, this system is transformed into an arrow form matrix representation. Using M-matrix properties, novel sufficient stability conditions are determined. It is shown how to use our method to design a state feedback controller that stabilizes a discrete time Lure system with time varying delay and sector bounded nonlinearity. The originalities of our findings are shown in their explicit representation, using system’s parameters, as well as in their easiness to be employed. The obtained results demonstrate also that checking stability of a nonlinear discrete time systems with time varying delay can be reduced to an M-matrix test. Several examples are provided to show the effectiveness of the introduced technique.

7 Stabilizing PID Controllers for a Class of Time Delay Systems

It is well known that delay exists in many practical systems such as industrial systems, biologic... more It is well known that delay exists in many practical systems such as industrial systems, biological systems, engineering systems, population dynamic models, etc... Time delay may appear as part of the internal dynamics or may result because of the actuators and sensors used. Communication delays between different parts of a system are also sources of this phenomenon. Existence of time delays may cause oscillations and even instability; moreover it complicates the analysis and control of these systems (Zhong, 2006; Normey-Rico & Camacho, 2007). For all these reasons there is an extensive literature on stability analysis, stabilization and control of time delay processes, which continue to be active areas of research.

Routing in IoT Lossy Networks: Potential Issues and Proposed Changes

Journal of Interconnection Networks

The specificities of the Internet of Things (IoT) require innovative methods to perform routing, ... more The specificities of the Internet of Things (IoT) require innovative methods to perform routing, owing to the resource limitations of network nodes. The IPv6 routing protocol for low-power and lossy networks ( RPL), as one of these pioneering methods, performs a variety of routing measurements to meet the requirements of some IoT applications, but, does not solve the problems of sudden and intense data traffic caused by the particularity of the other ones. Indeed, it has been observed that such unexpected and excessive data traffic leads to routing instability and traffic congestion in the IoT network. In order to overcome the mentioned shortcomings, we propose a common solution using the mobility of some nodes to reduce system instability and alleviate congestion on the network, to be named: use of mobile node for the Instability & Congestion Alleviation in IoT networks (mob-ICA). Therefore, our contribution consists in overcoming network instability by dynamically regulating the m...

Stabilization Domains for Second Order Delay Systems

IEEE Access

In this paper, an analytic condition is given for determining delayed positive feedback controlle... more In this paper, an analytic condition is given for determining delayed positive feedback controller for stabilizing an oscillatory system. The τ-decomposition and D-decomposition methods are employed in deriving this condition. The obtained results are then used to stabilize second order delay systems by a proportional controller. Under-damped and over-damped systems are treated separately, where the Smith-predictor structure is used in the over-damped case to obtain the stability conditions. Illustrative examples are given to show the effectiveness of the proposed approach. INDEX TERMS Delayed positive feedback, τ-decomposition, D-composition, stability domains, time delay systems.

Sécurité des machines

COURS : La sécurité des machines et comment concevoir un système de sécurité, 2024

La sécurité des machines et comment concevoir un système de sécurité

cours signaux et systèmes discrets

recherches opérationelles

www.icmcsd-13.com

Analytical Stability Conditions on Interconnected Nonlinear Systems with Delays

IEEE Access, 2021

This paper is concerned with stability of interconnected systems with time delays. We develop a s... more This paper is concerned with stability of interconnected systems with time delays. We develop
a self-contained approach to stability analysis for linear and nonlinear systems in a unified framework. New
lemmas are established on matrix properties and used as the key to make negativity of the derivative of the
Lyapunov function. The scalar and simple analytical stability conditions are given. Unlike the majority of
the literature on stability of delay systems, no matrix equations/inequalities are involved in our conditions,
which is true even for large-scale systems and nonlinear subsystems with delayed interconnections. They
are applicable to the more general nonlinear, time-varying, and/or interconnected systems than the relevant
results reported in the literature. The examples are presented for illustration of the new result