Delay-dependent stability criteria for a class of networked control systems with multi-input and multi-output☆

This paper is concerned with stability criteria of networked control systems (NCSs) with both the time-varying network-induced delay and data packet dropout taken into account. A continuous time model of NCSs with time-varying and uncertainties is proposed. Based on the dividing of the time-varying delay, a new Lyapunov functional is constructed, and a delay-dependent stability criterion is derived to guarantee the globally asymptotic stability of the networked control systems (NCSs). Expressed in terms of linear matrix inequalities (LMIs), the stability condition can be checked using the numerically efficient Matlab LMI Control Toolbox. Compared with some report methods, no slack matrix variable is introduced and the proposed methods gave a much less conservative maximum allowable delay bound (MADB). A numerical example is provided to demonstrate the effectiveness of the proposed method.

A new model for networked control systems (NCSs) with structured uncertainties and multiple state time-delays is presented, In view of multi-input and multi-output (MIMO) NCSs with many independent sensors and actuators, a continuous time model of NCSs with distributed time-delays and uncertainties are proposed. A method of delay-estimation online is also given. Then a scheme based on LQG controller is designed to achieve desired Real-time performance. The result illustrate that the effectiveness of the proposed control design and the satisfactory performance of the system.

The problem of stabilization of networked control systems (NCSs) with time-varying transmission delays is investigated. The time-varying delays lie in any two adjoining sampling instants of the plant. A technique is proposed for designing stabilizing controllers by converting NCSs with time-varying transmission delays into parameter uncertain systems with constant input delay, then the theory of robust stabilization of delay systems can be applied to solving this problem. Sufficient condition on stabilization of such NCSs is developed in terms of linear matrix inequality.

This paper deals with time delays which exist in networked control systems due to presence of communication network. Time delay impact on networked control system stability is analyzed, and some relations for maximum allowable delay bound estimation are given as well. It is shown, on example of DC motor control, that the system behaves in desired manner and remains stable when appropriate values of regulator parameters are chosen to match estimated maximum time delay.

The problem of stabilization of networked control systems (NCSs) with data packet dropout is studied. Sufficient conditions are presented on the stability and stabilization of the NCSs with packet dropout. The novelty of this work lies in that NCSs with arbitrary but finite data packet dropout are modelled as switched linear systems, and this enables us to apply the result of switched systems to the analysis and synthesis of such NCSs. The admissible upper bound of the dropped packets can be determined by a set of linear matrix inequalities (LMIs) which guarantee the stability of the NCSs. Stabilizing controllers (via state feedback and static output feedback) can be constructed by solving a set of LMIs. Also, for an NCS with a convergence rate constraint, similar results are obtained. Examples are worked out to illustrate the effectiveness of the proposed method

In this article, we characterize the joint effects of plant uncertainty, transmission delay, and fading channel on the stabilization problem of networked control systems (NCSs). We assume that the controller remotely controls the plant and the control packet is transmitted over a delayed and fading channel. We formulate the integrated system as an uncertain discrete-time stochastic system with both input delay and multiplicative noise. The innovative contributions of this article are described as follows. We propose a set of necessary and sufficient conditions for stabilizing an uncertain-free system. Moreover, for the general uncertain model, we derive the necessary and sufficient stabilization condition in terms of symmetric matrix homogeneous polynomials, which can be verified by linear matrix inequality (LMI) feasibility test. As an application, under the parallel transmission strategy, we derive an explicit formula for computing the maximum allowable delay bound, which is uniquely determined by system parameters and signal-to-noise ratio.

It is well known that the modeling issues in Dynamical systems in chemical processes, networked control systems and automation systems are very complex and model may contain subsystems with different delays. Because of the mathematical complexity, the robust control of these types of multiple time delay system is a challenging one. The problem becomes more difficult and complex when the system is having time delays in both the denominator and the numerator. In this paper a new method is proposed for approximating general multiple time delay continuous-time transfer function system with multiple time delays in both the denominator and the numerator to a single input/output delay. Both Single Input Single Output(SISO) and Multi Input Multi Output(MIMO) cases have been considered. In this proposed methodology, the Approximated Generalized Time Moments (AGTM)/ Approximated Generalized Markov Parameter (AGMP) methods are used to transform the multiple time delay system into a single input/output delay system. A Linear Matrix Inequality (LMI) approach is developed for synthesizing robust H∞ control of the approximated time delay system. The efficacy of the proposed method is shown through illustrative examples. It is evident from the simulation results that the approximated system is stable with the proposed LMI H∞ controller.

The state feedback absolutely stabilizing controller for a class of networked control system is designed. Supposed that the network time-delay is random, the networked control system that the plan is a class of time-delay systems with nonlinearities satisfying a given sector condition is modeled as a hybrid system. Furthermore, the Lyapunov-Krasovskii function and linear matrix inequality methods are used to derive a sufficient condition, which can guarantee that the networked control system is absolute stable. Based on the sufficient condition, in terms of convex optimization techniques, the controller and the maximum allowable transfer interval are obtained easily. The numerical and simulation example are presented to demonstrate the effectiveness of the approach.

Input-to-state stability for networked control system with predictive scheme

This paper is concerned with the robust stabilization problem for a class of networked control systems with nonlinear perturbations. The perturbations are assumed to be time-varying and satisfying quadratic constraints. Such networked control systems are modeled as systems with time-varying delays. Based on this model, observer-based controllers are designed to stabilize the nonlinear systems subject to the network-induced delay and data dropout. Sufficient conditions on existences of the stabilizing controllers are established. The controller gains can be obtained by solving a set of linear matrix inequalities. An illustrative example is given to demonstrate the effectiveness of the proposed method.

This paper focuses on the fault-tolerant control (FTC) of networked control systems (NCSs) with packet dropouts using switched system approach. The basic idea is to model such NCSs as a discrete-time switched system. Thus, the FTC of such NCSs can be reduced to that of switched systems. Sufficient conditions are presented about the stabilization of NCSs. Stabilizing switched state/output feedback controllers can be constructed by solving a set of linear matrix inequalities (LMIs), which can be easily tested with efficient LMI algorithms. The maximum allowable dropout bound can be obtained by solving an optimization problem.

Input-output finite-time stability for networked control systems with memory event-triggered scheme

The problem of data packet dropout induced by communication channel in networked control systems (NCSs) is studied in this paper. We model the NCSs with data packet dropout as jump linear systems. With a freedom matrix introduced, new equivalently sufficient conditions on the mean square stabilisation of NCSs are obtained in terms of linear matrix inequalities (LMIs). Constant stabilising state-feedback controllers can then be constructed by using the feasible solutions of some LMIs. A numerical example illustrates the effectiveness of the proposed approach.

This article addresses the problem of controller design for networked control systems over digital communication. The systems under consideration are stabilised via state feedback, where the effects of sampled signal, state quantisation, network-induced delay and packet dropout are considered. The proposed delay-dependent stability criteria are formulated in the form of a linear matrix inequality, which ensure asymptotic stability and a prescribed H ∞ performance level for networked control systems with admissible uncertainties. Maximum allowable delay bound of networked control systems is obtained by solving a convex optimisation problem. Furthermore, a numerical example is given to illustrate the effectiveness of the main result.

A switched system approach is proposed to model networked control systems (NCSs) with communication constraints. This enables us to apply the rich theory of switched systems to analyzing such NCSs. Sufficient conditions are presented on the stabilization of NCSs. Stabilizing state/output feedback controllers can be constructed by using the feasible solutions of some linear matrix inequalities (LMIs). The merit of our proposed approach is that the behavior of the NCSs can be studied by considering switched system without augmenting the system. A simulation example is worked out to illustrate the effectiveness of the proposed approach.