New stability conditions for class of nonlinear discrete-time systems with time-varying delay (original) (raw)
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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 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.
On Stabilizability of Discrete Time Systems with Delay in Control
2020
The paper deals with discrete time-invariant systems with a delay in the control variable. The relations between different types of controllability and stabilizability are presented and discussed. The results are related to asymptotic null controllability, bounded feedback stabilizability and small feedback stabilizability for linear discrete-time systems with delay in control. The main tool employed is the technique of reducing the delayed equation to a delay-free equation. Thanks to this idea the criteria for bounded feedback stabilizability and small feedback stabilizability for the delayed systems are expressed in the appropriate properties of delay-free systems. Main results are analogical of this one proved in [18] for discrete time-invariant delay-free systems and to those from [14] for continuous-time systems. One of the additional result of this paper provides a criterion for controllability of discrete time system with delay in control. An important contribution of this pa...
Output Feedback Stabilization for a Discrete-Time System With a Time-Varying Delay
IEEE Transactions on Automatic Control, 2008
This study employs the free-weighting matrix approach to investigate the output feedback control of a linear discrete-time system with an interval time-varying delay. First, the delay-dependent stability is analyzed using a new method of estimating the upper bound on the difference of a Lyapunov function without ignoring any terms; and based on the results, a design criterion for a static output feedback (SOF) controller is derived. Since the conditions thus obtained for the existence of admissible controllers are not expressed strictly in terms of linear matrix inequalities, a modified cone complementarity linearization algorithm is employed to solve the nonconvex feasibility SOF control problem. Furthermore, the problem of designing a dynamic output feedback controller is formulated as one of designing an SOF controller. Numerical examples demonstrate the effectiveness of the method and its advantage over existing methods.
Journal of Control Engineering and Applied Informatics, 2017
This paper discusses the problem of delay-dependent stability and stabilization condition for discrete-time linear systems. By employing a three-term approximation for delayed state variables, a new model transformation is developed, which has a smaller approximation error than the two-term approach. By using scaled small gain theorem and an appropriate Lyapunov-Krasovskii functional, new delay-dependent stability conditions are proposed and formulated as linear matrix inequalities (LMIs). Before the end, a state feedback controller has investigated in the stabilization of discrete linear systems. Finally, numerical examples are presented to illustrate the effectiveness of the proposed method.
The stability of linear discrete time delay systems over a finite time interval: New results
Proceedings of the 10th World Congress on Intelligent Control and Automation, 2012
This paper gives sufficient conditions for the practical and finite time stability of a particular class of linear discrete time delay systems. Analyzing the finite time stability concept, these new delay-independent conditions are derived using an approach based on the Lyapunov-like functions. The practical and attractive practical stability for discrete time delay systems has been investigated. The above mentioned approach was supported by the classical Lyapunov technique to guarantee the attractivity properties of the system behavior.
2011 9th IEEE International Conference on Control and Automation (ICCA), 2011
ABSTRACT This paper gives sufficient conditions for the practical and finite time stability of a particular class of linear discrete time delay systems. Analyzing the finite time stability concept, these new delay-independent conditions are derived using an approach based on the Lyapunov-like functions. The practical stability and attractive practical stability for discrete time delay systems have been investigated. The above mentioned approach was supported by the classical Lyapunov technique to guarantee the attractivity properties of the system behavior.
Robust stability and stabilization methods for a class of nonlinear discrete-time delay systems
Applied Mathematics and Computation, 2010
This paper establishes new robust delay-dependent stability and stabilization methods for a class of nonlinear discrete-time systems with time-varying delays. The parameter uncertainties are convex-bounded and the unknown nonlinearities are time-varying perturbations satisfying Lipschitz conditions in the state and delayed-state. An appropriate Lyapunov functional is constructed to exhibit the delay-dependent dynamics and compensate for the enlarged time-span. The developed methods for stability and stabilization eliminate the need for over bounding and utilize smaller number of LMI decision variables. New and less conservative solutions to the stability and stabilization problems of nonlinear discrete-time system are provided in terms of feasibility-testing of new parametrized linear matrix inequalities (LMIs). Robust feedback stabilization methods are provided based on state-measurements and by using observer-based output feedback so as to guarantee that the corresponding closed-loop system enjoys the delay-dependent robust stability with an L 2 gain smaller that a prescribed constant level. All the developed results are expressed in terms of convex optimization over LMIs and tested on representative examples.
Lyapunov and Non-Lyapunov Stabilty of Linear Discrete Time Delay Systems
This paper extends some of the basic results in the area of Lyapunov (asymptotic) and finite time and practical stability to linear, discrete, time invariant time-delay systems. New definitions have been established for the latter concept of stability. Sufficient conditions for this type of stability, concerning the particular class of linear discrete time-delay systems are derived. More over the generalization of some previous results, in the area of Lyapunov stability for the same class of systems has been also established and proved.
Nonlinear discrete-time systems with delayed control: A reduction
Systems & Control Letters, 2018
In this work, the notion of reduction is introduced for discrete-time nonlinear input-delayed systems. The retarded dynamics is reduced to a new system which is free of delays and equivalent (in terms of stabilizability) to the original one. Different stabilizing strategies are proposed over the reduced model. Connections with existing predictor-based methods are discussed. The methodology is also worked out over particular classes of time-delay systems as sampled-data dynamics affected by an entire input delay.
Journal of Control Engineering and Applied Informatics, 2017
This paper discusses the problem of delay-dependent stability and stabilization condition for discrete-time linear systems. By employing a three-term approximation for delayed state variables, a new model transformation is developed, which has a smaller approximation error than the two-term approach. By using scaled small gain theorem and an appropriate Lyapunov-Krasovskii functional, new delaydependent stability conditions are proposed and formulated as linear matrix inequalities (LMIs). Before the end, a state feedback controller has investigated in the stabilization of discrete linear systems. Finally, numerical examples are presented to illustrate the effectiveness of the proposed method.