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2011, Ima Journal of Mathematical Control and Information
The paper is concerned with a class of time-delay systems that are linearly equivalent to higher-order scalar equations. If the retarded case was considered some four decades ago in Halanay (1969), the nontrivial neutral case is considered here. The specific structure of these systems endows them with remarkable properties that are useful in various applications in dynamics and control. As an auxiliary necessary result, the variation of parameters formula is revisited what opens new perspectives for research progress in such directions as the Perron condition and forced linear oscillations.
2011
In this work, delay-dependent stability conditions for systems described by delayed differential equations are presented. The employment of a special transformation to a state space representation named Benrejeb characteristic arrow matrix permits to determine new asymptotic stability conditions. Illustrative examples are presented to show the effectiveness of the proposed approach.
Physical Review E, 2004
The characteristics of a time-delayed system with time-dependent delay time is investigated. We demonstrate the nonlinearity characteristics of the time-delayed system are significantly changed depending on the properties of time-dependent delay time and especially that the reconstructed phase trajectory of the system is not collapsed into simple manifold, differently from the delayed system with fixed delay time. We discuss the possibility of a phase space reconstruction and its applications.
2000
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IEEE Transactions on Automatic Control, 2000
We demonstrate that some delay-differential equations of neutral type are, up to basis transformation, equivalent to retarded delay differential equations. In particular, for two classes of neutral delay differential equation models, we use state transformations to show that delayed derivatives can in some cases be expressed in terms of the model's state. Hence, we obtain conditions when neutral delay differential equations can be transformed into retarded delay differential equations.
In this work, delay-dependent stability conditions for systems described by delayed differential equations are presented. The employment of a special transformation to another state space representation named Benrejeb characteristic arrow matrix permit to determine a practical asymptotic stability condition. An Illustrative example is presented permitting to understand the application of the proposed methods.
Automatica, 2004
Chemical Engineering Science, 1989
We study the dynamics of a general system under linear feedback control subject to system, measuremctit and actuator delays. There are two general classes of dynamic behavior, resonant and nonresonant, which are pertinent to the tuning of the controllers and to the nonlinear closed-loop dynamics. For non-resonant systems, the cross-over frequency and ultimate gain are monotonic and continuous functions of the delay and conventional Ziegler-Nichols type tuning methods are appropriate. For resonant systems, however, the cross-over frequency is a discontinuous function of the delay and at certain critical values of the delay, two cross-over frequencies coexist at the same ultimate gain. Such systems cannot be tuned with the Ziegler-Nichols methods. These critical delays of a resonant system cot-respond to double-Hopf bifurcation points with two distinct pairs of purely imaginary eigenvalues (closed-loop poles). Using center manifold projection and normal form analyses, we are able to predict all nonlinear dynamics in the vicinity of these singularities. In particular, a two-frequency torus is always found. This is verified experimentally in a cascaded liquid level control system. There is also evidence that the torus degenerates into a chaotic attractor as the feedback gain is increased.
Mathematics
We introduce the delayed sine/cosine-type matrix function and use the Laplace transform method to obtain a closed form solution to IVP for a second-order time-delayed linear system with noncommutative matrices A and Ω. We also introduce a delay Gramian matrix and examine a relative controllability linear/semi-linear time delay system. We have obtained the necessary and sufficient condition for the relative controllability of the linear time-delayed second-order system. In addition, we have obtained sufficient conditions for the relative controllability of the semi-linear second-order time-delay system. Finally, we investigate the Ulam–Hyers stability of a second-order semi-linear time-delayed system.
Automatica, 2009
This paper is concerned with stability of linear time-delay systems of both retarded and neutral types by using some new simple quadratic Lyapunov-Krasovskii functionals. These Lyapunov-Krasovskii functionals consist of two parts. One part comes from some existing Lyapunov-Krasovskii functionals employed in . Absolute stability of time-delay systems with sector-bounded nonlinearity. Automatica, 41, 2171Automatica, 41, -2176. A new delay-dependent stability criterion for linear neutral systems with norm-bounded uncertainties in all system matrices. International Journal of Systems Science, 36,[469][470][471][472][473][474][475]. The other part is constructed by uniformly dividing the discrete delay interval into multiple segments and choosing proper functionals with different weighted matrices corresponding to different segments. Then using these new simple quadratic Lyapunov-Krasovskii functionals, some new discrete delay-dependent stability criteria are derived for both retarded systems and neutral systems. It is shown that these criteria for retarded systems and neutral systems are always less conservative than the ones in Han (2005a) and Han (2005b) cited above, respectively. Numerical examples also show that the results obtained in this paper significantly improve the estimate of the discrete delay limit for stability over some other existing results.
Journal of Mathematical Analysis and Applications, 1975
intechopen., 2018
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.
1980
In this paper a class of delay differential systems is studied using an al~ebraic approach. Such a system is considered a system over a ring of delay operators. The ring under consideration is a valuation domain. This fact enables us to construct canonical free realizations and also regulators and observers. Algorithms in order to perform these constructions are given. The results are improvements upon the case where a delay diffe~ential system with incommensurable delays is viewed as a system over a polynomial ring in several variables.
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.
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 2019
Time delays play an important role in many fields such as engineering, physics or biology. Delays occur due to finite velocities of signal propagation or processing delays leading to memory effects and, in general, infinite-dimensional systems. Time delay systems can be described by delay differential equations and often include non-negligible nonlinear effects. This overview article introduces the theme issue ‘Nonlinear dynamics of delay systems’, which contains new fundamental results in this interdisciplinary field as well as recent developments in applications. Fundamentally, new results were obtained especially for systems with time-varying delay and state-dependent delay and for delay system with noise, which do often appear in real systems in engineering and nature. The applications range from climate modelling over network dynamics and laser systems with feedback to human balancing and machine tool chatter. This article is part of the theme issue ‘Nonlinear dynamics of delay...
2017
We introduce a framework for the description of a large class of delay-differential algebraic systems, in which we study three core problems: first we characterize abstractly the well-posedness of the initial-value problem, then we design a practical test for well-posedness based on a graph-theoretic representation of the system; finally, we provide a general stability criterion. We apply each of these results to a structure that commonly arises in the control of delay systems.
Dynamical Systems, 2009
Applied Mathematics E - Notes
Let A and B be real square matrices of dimension d 2 and r > 0. We consider the system X(t) = AX(t) + BX(t r); t 0; where X is speci…ed on the interval [ r; 0] and give explicit solutions for the system when the matrix A has a single eigenvalue, generalizing results of [7]. By decoupling, we obtain explicit representations for solutions of a certain class of these systems in which A has several distinct eigenvalues.
Theoretical and Applied Mechanics, 2013
This paper deals with the problem of delay dependent stability for both ordinary and large-scale time-delay systems. Some necessary and sufficient conditions for delay-dependent asymptotic stability of continuous and discrete linear time-delay systems are derived. These results have been extended to the large-scale time-delay systems covering the cases of two and multiple existing subsystems. The delay-dependent criteria are derived by Lyapunov's direct method and are exclusively based on the solvents of particular matrix equation and Lyapunov equation for non-delay systems. Obtained stability conditions do not possess conservatism. Numerical examples have been worked out to show the applicability of results derived.
2013 International Conference on Control, Decision and Information Technologies (CoDIT), 2013
In this paper a new practical stability conditions for delayed Lur'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.
Automation and Remote Control, 2011
Results were presented enabling one to reduce the problem equilibrium stability for multidimensional delay systems to a similar problem for more than one system of lower dimensionality. The results were established using fixed-sign (degenerate) Lyapunov functions and the limiting systems. The latter were constructed under more general assumptions about the right-hand side of the system than those used traditionally.
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