Yan-Wu Wang

Synchronization of Complex Dynamical Networks With Time-Varying Delays Via Impulsive Distributed Control

In this paper, the synchronization of complex dynamical networks (CDNs) with system delay and multiple coupling delays is studied via impulsive distributed control. The concept of control topology is introduced to describe the whole controller structure, which consists of some directed connections between nodes. The control topology can be designed either to be the same as the non-delayed coupling topology of the network, or to be independent of the intrinsic network topology. Based on the concept of control topology, an impulsive controller is designed to achieve the exponential synchronization of CDNs, and moreover, the exponential convergence rate can be specified. Illustrated examples have been given to show the effectiveness of the proposed impulsive distributed control strategy.

Feedback and adaptive control for the synchronization of Chen system via a single variable

This Letter addresses control for the synchronization of chaotic Chen systems via a single variable. Two control approaches, namely a linear feedback controller and an adaptive controller, are investigated. In both cases sufficient conditions for the synchronization are obtained analytically. The control performances are verified by numerical simulations.

Finite-Time Consensus for Leader-Following Second-Order Multi-Agent Networks

This paper studies the leader-following finite-time consensus problem for the second-order multi-agent networks with fixed and switched topologies. Based on the graph theory, matrix theory, homogeneity with dilation and LaSalles invariance principle, finite-time consensus protocols are designed by the pinning control technique without assuming that the interaction graph is connected or the leader is globally reachable. Moreover, the control protocol of each agent using local information is presented, and some examples and simulation results are given to illustrate the effectiveness of the obtained theoretical results.

Robust Stabilization of Complex Switched Networks With Parametric Uncertainties and Delays Via Impulsive Control

In this paper, a general complex switched network (CSN) model is presented. The model is more general than those in the literatures in which it contains switching behaviors on both its nodes and topology configuration. Robust stabilization of directed time-varying CSN with parametric uncertainties and two types of delays is investigated. The two types of delays consist of the system delay at each node and the coupling delay between nodes. Based on the Lyapunov stability theory, sufficient robust stabilization conditions are proposed for CSNs via impulsive control. In addition, four special stabilization cases: CSNs with both system and coupling delays, CSNs with parametric uncertainties and either the system delay or the coupling delay, and complex networks with parametric uncertainties and both type of delays, are discussed. A systematic design procedure for stabilizing impulsive control is presented. A numerical example is provided for illustration. A comparative study of the stability ranges of the impulsive intervals corresponding to the general case of the directed time-varying CSN and the four special cases is carried out by simulation.

Impulsive control for synchronization of a class of continuous systems

An impulsive control theory for synchronization of a class of continuous systems is developed. A sufficient condition for the impulsive control is derived. The proposed impulsive control scheme is illustrated by some continuous chaotic systems and the simulation results demonstrate the effectiveness of the method.

Global Synchronization of Complex Dynamical Networks Through Digital Communication With Limited Data Rate

This paper studies the global synchronization of complex dynamical network (CDN) under digital communication with limited bandwidth. To realize the digital communication, the so-called uniform-quantizer-sets are introduced to quantize the states of nodes, which are then encoded and decoded by newly designed encoders and decoders. To meet the requirement of the bandwidth constraint, a scaling function is utilized to guarantee the quantizers having bounded inputs and thus achieving bounded real-time quantization levels. Moreover, a new type of vector norm is introduced to simplify the expression of the bandwidth limit. Through mathematical induction, a sufficient condition is derived to ensure global synchronization of the CDNs. The lower bound on the sum of the real-time quantization levels is analyzed for different cases. Optimization method is employed to relax the requirements on the network topology and to determine the minimum of such lower bound for each case, respectively. Simulation examples are also presented to illustrate the established results.

Synchronization of Continuous Dynamical Networks With Discrete-Time Communications

In this paper, synchronization of continuous dynamical networks with discrete-time communications is studied. Though the dynamical behavior of each node is continuous-time, the communications between every two different nodes are discrete-time, i.e., they are active only at some discrete time instants. Moreover, the communication intervals between every two communication instants can be uncertain and variable. By choosing a piecewise Lyapunov-Krasovskii functional to govern the characteristics of the discrete communication instants and by utilizing a convex combination technique, a synchronization criterion is derived in terms of linear matrix inequalities with an upper bound for the communication intervals obtained. The results extend and improve upon earlier work. Simulation results show the effectiveness of the proposed communication scheme. Some relationships between the allowable upper bound of communication intervals and the coupling strength of the network are illustrated through simulations on a fully connected network, a star-like network, and a nearest neighbor network.

Adaptive pinning cluster synchronization of fractional-order complex dynamical networks

The problem about cluster synchronization of fractional-order CDNs is studied via a pinning adaptive approach in this paper. Based on the stability theory of fractional differential equations, some sufficient criteria for local and global cluster synchronization of fractional-order CDNs are derived. In this paper, the coupling configuration matrix can be asymmetric as well as reducible and the inner coupling matrix can also be asymmetric. Moreover, the number of pinning nodes in each cluster can be evaluated. Especially, when the coupling strength is large enough and the coupling configuration matrix is symmetric, cluster synchronization can be achieved via pinning a single node in each cluster. Finally, some typical examples are given to illustrate the correctness and effectiveness of our results, a surprising finding is that the synchronization performance will become better as the fractional order decreases in this simulation.

Impulsive Multisynchronization of Coupled Multistable Neural Networks With Time-Varying Delay

This paper studies the synchronization problem of coupled delayed multistable neural networks (NNs) with directed topology. To begin with, several sufficient conditions are developed in terms of algebraic inequalities such that every subnetwork has multiple locally exponentially stable periodic orbits or equilibrium points. Then two new concepts named dynamical multisynchronization (DMS) and static multisynchronization (SMS) are introduced to describe the two novel kinds of synchronization manifolds. Using the impulsive control strategy and the Razumikhin-type technique, some sufficient conditions for both the DMS and the SMS of the controlled coupled delayed multistable NNs with fixed and switching topologies are derived, respectively. Simulation examples are presented to illustrate the effectiveness of the proposed results.

Time-varying formation tracking of multiple manipulators via distributed finite-time control

Compared with traditional fixed formation for a group of dynamical systems, time-varying formation can produce the following benefits: (i) covering the greater part of complex environments and (ii) collision avoidance. This paper studies the time-varying formation tracking for multiple manipulator systems (MMSs) under fixed and switching directed graphs with a dynamic leader, whose acceleration cannot change too fast. An explicit mathematical formulation of time-varying formation is developed based on the related practical applications. A class of extended inverse dynamics control algorithms combined with distributed sliding-mode estimators are developed to address the aforementioned problem. By invoking finite-time stability arguments, several novel criteria (including sufficient criteria, necessary and sufficient criteria) for global finite-time stability of MMSs are established. Finally, numerical experiments are presented to verify the effectiveness of the theoretical results.