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This paper presents a networked control systems (NCS) framework for wide area monitoring control of smart power grids. We consider a scenario in which wide area measurements are transmitted to controllers at remote locations. We model the effects of delays and packet dropouts due to limited communication capabilities in the grid. We also design a robust networked controller to damp wide-area oscillations based on information obtained from Wide Area Monitoring Systems (WAMS), and analyze the improvement in system stability due to networked control. With communication integration being an important feature of the smart grid, detailed consideration of the effects of communication is essential in the control design for future power systems. We believe that this work is an essential step in this direction. [ABSTRACT FROM PUBLISHER]

This paper presents a networked control systems (NCS) framework for the coordinated control of distributed generation sources in smart power grids. The system measurements are transmitted to the controller through a realtime communication network. The effects of delays and packet dropouts due to the communication network are modeled and networked controllers are designed to stabilize the system in the presence of small disturbances. As integrated communication infrastructure has become an indispensable part of the smart grid, detailed consideration of the effects of communication is an essential step in the control design for future power systems. [ABSTRACT FROM PUBLISHER]

In this paper, an-LMI approach is utilized for the stabilization of Discrete-Time Delay Nonlinear Systems (DTDNS). The delay provided is state-delay. The control criterion is derived in terms of linear matrix inequalities (LMI's). The controller is designed by making use of back stepping technique. By choosing an appropriate Lyapunov function, some mathematical manipulations have been carried out to deduce simple LMI condition for asymptotic stabilization. The effectiveness and the applicability of the proposed control law is verified through simulation. [ABSTRACT FROM PUBLISHER]

The problem of exact (and global) bilinearization of nonlinear delay systems is considered for an algebraic system's function in two dimension. It is proven that a nonlinear map (bilinearizing map) can be defined on the functional space of state's trajectories such that the image-system, defined through this map, of the original system, is in general a bilinear hybrid system, evolving in the same state-space as the original, but switching among a family of bilinear delayed systems. For constant delays, equal for each state component, such hybrid system reduces to switching among just two bilinear systems working on two disjoint intervals (the second interval unbounded) partitioning the original system's time domain. Finally, an algorithm is defined which allows the recursive inversion of the bilinearizing map thus recovering the original system's state, and proving the equivalence of the bilinear representation at issue with the original nonlinear system. The paper is a first step towards a general exact bilinearization of nonlinear delayed systems having an any-order algebraic, and even analytical, system's functions. [ABSTRACT FROM PUBLISHER]

This paper is focused on the problem of ℋ∞ filtering for a class of discrete-time T-S fuzzy time-varying delay systems. Our interest is how to design full- and reduced-order filters that guarantee the filtering error system to be asymptotically stable with a prescribed ℋ∞ performance. Sufficient conditions for the obtained filtering error system are proposed by applying an input-output approach and a two-term approximation method, which is employed to approximate the time-varying delay. The corresponding full and reduced-order filter design is cast into a convex optimization problem, which can be efficiently solved by standard numerical algorithms. [ABSTRACT FROM PUBLISHER]

This paper is concerned with analyzing a novel model transformation of discrete-time Takagi-Sugeno (T-S) fuzzy systems with time-varying delays and applying it to dynamic output feedback (DOF) controller design. A new auxiliary model is proposed by employing a new approximation for time-varying delay state, and then delay partitioning method is used to analyze the scaled small gain of this auxiliary model. A sufficient condition on discrete-time T-S fuzzy systems with time-varying delays, which guarantees the corresponding closed-loop system to be asymptotically stable and has an induced ℓ2 disturbance attenuation performance, is derived by employing the scaled small gain theorem. Then the solvability condition for the induced ℓ2 DOF control is also established, by which the DOF controller can be found by solving a set of linear matrix inequalities (LMIs). [ABSTRACT FROM PUBLISHER]

We consider a large class of fractional delay systems with many neutral chains of poles approaching a same set of points on the imaginary axis. As a primary work regarding H∞-stability analysis, high modulus poles of neutral chains are approximated. [ABSTRACT FROM PUBLISHER]

Time-delay phenomenon is often observed in scientific research and engineering practice. Due to the existence of the time-delay, a system could make oscillation, divergent, and even lead to instability, and neutral time-delay system delay exists not only in the system state, still exists in the derivative to the state of the system, more difficult to calm, so the stability analysis has theoretical research and practical application value, nearly two decades, many scholars have pay attention to it. This paper based on the spectrum decomposition theory, which analysis the neutral constant delay system stability, neutral time-varying delay system stability in the design of controller model in chemical process of doublestage dissolved slot. Based on such model, we can get a better solution to the chemical control. [ABSTRACT FROM PUBLISHER]

This paper further investigates the problems of robust H∞ control for uncertain Takagi-Sugeno (T-S) fuzzy neutral systems with distributed time delays. The purpose is to design state feedback fuzzy controllers such that the resulting closed-loop system is robustly stable with an H∞ performance level. Two Sufficient conditions for the solvability of the problem are obtained by utilizing a Lyapunov functional together with the relaxed linear matrix inequality (LMI) approach. A numerical example is provided to demonstrate the applicability of the two proposed design method and difference between them are also discussed. [ABSTRACT FROM PUBLISHER]

In this paper, the optimal impulsive control problem for a class of switched autonomous system with time-delay is studied. The considered system jumps at the switching times and the state is only partially known through the outputs. The control variables are the instants when the switches occur, and a set of scalars which determine the jump amplitudes. A method is presented that guarantees that the current switch time remains optimal as the state estimates evolve, and can be applied to real-time applications. The optimal impulsive control strategy can then be found using a numerical gradient descent algorithm. [ABSTRACT FROM PUBLISHER]

This paper is concerned about the recursive linear-quadratic(LQ) optimal control problem for delay systems involving both continuous and impulse controls. The explicit form of the unique optimal control is given under some appropriate conditions via a kind of forward-backward differential equations and its existence and uniqueness are also be proved. [ABSTRACT FROM PUBLISHER]

The paper presents an application of the Puiseux-Newton diagram associated with the Reduction Theorem (a simple case of Weierstrass Preparation Theorem) to the study of linear time-invariant delay systems, focusing on the asymptotic behavior of critical characteristic roots on the imaginary axis which is necessary for the stability analysis. With the systems given in quasi-polynomials, we characterize the asymptotic behaviors of the characteristic roots of such systems in an algebraic way and determine whether the imaginary roots cross from one half plane into another or only touch the imaginary axis. An analogue of Weierstrass Preparation Theorem has been proposed to reduce the characteristic equation to the algebraic equation whose explicit expression is also given in this paper, from which the classic Puiseux-Newton diagram can be used to obtain the asymptotic expansions directly. Some illustrative examples complete the paper. [ABSTRACT FROM PUBLISHER]

This paper is concerned with the problems of almost sure (a.s.) stability and stabilization for stochastic systems with Markovian switching (SSMS) and time-varying delays. Some sufficient criteria on the stability for the underlying nonlinear stochastic systems is derived in terms of continuous semimartingale convergence theorem and Doob's martingale inequality. The purpose of stabilization is to design linear state feedback control laws in the drift part so that the resulting closed-loop system is almost surely (a.s.) stable. Two numerical simulation examples are exploited to verify the effectiveness of the theoretical results. [ABSTRACT FROM PUBLISHER]

This paper considers output feedback stabilization problem for a class of high-order stochastic nonlinear time-delay systems. By introducing the adding a power integrator technique in the stochastic case and a rescaling transformation, and choosing an appropriate Lyapunov-Krasoviskii functional, an output feedback controller is constructed to render the closed-loop system globally asymptotically stable in probability and the output can be regulated to the origin almost surely. [ABSTRACT FROM PUBLISHER]

Stability analysis and control for linear periodic time-delay systems described by state space models are investigated in this paper. Semi-discretization method is used to develop a mapping of the system response in a finite-dimensional state space. The stability region and stability boundary can be found by comparing the maximum absolute value of the mapping's eigenvalues with 1. More importantly, an efficient stability criterion is presented for linear periodic neutral systems. Besides, minimization of the maximum absolute value of the mapping's eigenvalues leads to optimal control gains. Two numerical examples are given to illustrate the proposed method's effectiveness. [ABSTRACT FROM PUBLISHER]

We have considered semi-linear stochastic delay systems with Lévy noise. First we study Lévy processes in Hilbert space and present the result for Lévy processes in Hilbert space that the processes can be present as the sum of the series. Then we apply the result to investigate the approximate controllability for stochastic delay systems with Lévy noise. The sufficient conditions for approximate controllability results are established for these stochastic delay systems [ABSTRACT FROM PUBLISHER]

This paper considers the problem of robust stability and stabilization of uncertain time delay systems. We focus on the class of Metzlerian delay systems and use the interesting properties of Metzler matrix to provide the necessary ingredients for the main results of the paper. It is shown that Metzlerian delay system is asymptotically stable if and only if the Metzlerian system without delay∗ is asymptotically stable. This fact allows one to establish strong results on constrained stabilization for delay systems. The robust stability of Metzlerian delay system is also revisited and, without requiring long derivation, direct formulas for calculating the stability radius of this class of systems are provided. Finally, we consider the problem of constrained robust stabilization of interval delay systems and outline an LMI based solution for it. The paper concludes with two numerical examples to support the theoretical results. [ABSTRACT FROM PUBLISHER]

Obtaining the Puiseux Series expansion of multiple imaginary (characteristic) roots (MIRs) is a fundamental issue in the stability analysis of time-delay systems. However, this issue has not been fully investigated up to date. This work focuses on the Puiseux Series expansion of MIRs for a class of linear time-delay systems including commensurate delays. For an MIR of any multiplicity, we propose an algorithm for defining the structure of the Puiseux Series, as well as the explicit computation of the corresponding coefficients. By using the proposed method, we can find all the Puiseux Series corresponding to all the root trajectories. Some illustrative examples complete the work. [ABSTRACT FROM PUBLISHER]

In this paper, the problem of non-fragile observer-based H∞ control for discrete-time switched delay systems is investigated. Both data missing and time delays are taken into account in the links from sensors to observers and from controllers to actuators. Such problem is transformed into an H∞ control problem for stochastic switched delay systems. Average dwell time (ADT) approach is used to obtain sufficient conditions on the solvability of such problems. An example is provided to show the effectiveness of the proposed method. [ABSTRACT FROM PUBLISHER]

This paper proposes a controller design based on sum-of-squares (SOS) method for time-varying delay systems. The SOS condition for controller design and the proof based on the Lyapunov-Krasovskii stability theorem are shown. The performance of the controller is fine-tuned taking into account input-output property. The controller is solved by decomposing a SOS condition, which is given by convex form. Experimental results on a real plant are also described to evaluate the performance of the proposed method. [ABSTRACT FROM PUBLISHER]

Distributed Media Plays (DMP) is a futuristic architecture for the Internet. It is specifically designed keeping in mind that a number of futuristic Internet services have real-time constraints, particularly the end-to-end delay has to be less than 20 ms. These constraints need to be fulfilled by the network and the current RTP/UDP/IP protocol stack is found to be limited in this regard. Thus an alternative network architecture is proposed and being developed with special, although compatible with IPv6, packets. The handling of these packets in DMP network is explained in this paper. The foundation of DMP system is laid on the quality requirements of the futuristic Internet services. Therefore, one of the features of DMP is that the content quality is gracefully degraded in case the network is overloaded and the traffic injection has to be reduced. This is provided by introducing a scheme for ``Quality Shaping'' which is explained in detail in this paper. Also a new ``Link Flow Control (LFC)'' functionality is introduced in DMP architecture to enhance quality control of contents, which is also explained herein. The LFC functionality helps the DMP network nodes to have an overview of the capacity bottlenecks in the network and hence adjust the traffic flow accordingly. [ABSTRACT FROM PUBLISHER]

In this paper, the problem of feedback stabilization of stochastic differential delay systems is considered. The systems under study are nonlinear, nonaffine and involve both discrete and distributed delays. By using a LaSalle-type theorem for stochastic systems, general conditions for stabilizing the closed-loop system with delays are obtained. In addition, stabilizing state feedback control laws are proposed. [ABSTRACT FROM PUBLISHER]

In the present paper the linear feedback equivalence problem is addressed for time delay systems. It is shown that thanks to the use of new mathematical tools recently introduced in the literature for dealing with time delay systems, it is possible to define necessary and sufficient conditions for the solvability of the problem. [ABSTRACT FROM PUBLISHER]

The accessibility of the class of driftless single-input nonlinear time-delay systems is fully characterized for the first time. This result is obtained through the introduction of new tools within a geometric approach recently introduced in the literature. Moreover, all those possible autonomous elements, which can depend on the variables with time-delay, are also characterized when the system is not accessible and in consequence, a canonical form of those systems is deduced. [ABSTRACT FROM PUBLISHER]

Finite-dimensional controller synthesis methods are developed for some classes of linear, time-invariant, single-input single-output, or multi-input multi-output systems, which are subject to time delays. The proposed synthesis procedures give low-order stabilizing controllers that also achieve integral-action so that constant reference inputs are tracked asymptotically with zero steady-state error. [ABSTRACT FROM PUBLISHER]

For a broad class of H∞ preview/delayed control problems, a solvability condition is newly established based on an analytic solution of operator Riccati equation. The condition is characterized by maximal eigenvalue of a compact operator and enables us to overcome the limitation of existing methods. An H∞ control law is also clarified and some interpretation is provided based on the property of the analytic solution. Employing the advantage of proposed approach, a design method of H2 control law is derived for the preview/delayed systems. [ABSTRACT FROM PUBLISHER]

In this study, we investigate the problem of designing a linear state feedback control to stabilize a class of linear uncertain systems with state delay. We introduce the concept of an abstract delay system that can be used to characterize the behavior of a broad class of mathematical models that include delay differential equations. We examine the stabilization problem of an abstract delay system on a Banach lattice using semigroup theory. To tackle this problem, we take advantage of the properties of a nonnegative semigroup on a Banach lattice. The objective of this paper is to show that the stabilizability conditions obtained by a stability criterion of nonnegative semigroups have a particular geometric configuration with respect to the permissible locations of uncertain entries. For this purpose, we introduce a variable transformation method to eliminate a restrictive assumption such as the nonnegativity of a system. [ABSTRACT FROM PUBLISHER]