Synchronization In Networks Of Systems Research Articles

Finite‐time synchronization of network systems with linear and nonlinear couplings via quantized intermittent‐adaptive control

AbstractThis paper investigates the synchronization problem of network systems (NSs) via finite‐time (FIT) control techniques. First, the network systems include two complex networks with linear couplings, nonlinear couplings and different rates of evolution. In order to realize the goal of synchronization, intermittent‐adaptive control schemes with quantizer are designed. Then, several FIT synchronization criteria are established by using the designed controllers whose parameters could be adjusted automatically according to the adaptive laws. At the rest of this article, the numerical simulations are provided to illustrate our results.

Synchronization in networks of systems with synchronous/asynchronous sampled-data couplings

This paper considers the network synchronization problem of nonlinear systems with sampled-data couplings. In particular, we focus on sufficient conditions for full synchronization of systems interconnected via sampled-data couplings. We have already derived a sufficient condition for synchronization of two mutual coupled systems whose outputs are simultaneously measured with the same constant sampling interval. By extending the result, in this paper, we show that the network synchronization condition can be estimated from that of two coupled systems by scaling the stability region with a factor related to the eigenvalues of the graph Laplacian. Furthermore, we discuss the effect of asynchronous sampling on synchronization. The validity of the obtained results is illustrated by numerical simulations.

Synchronization of Network Systems via Aperiodic Sampled-Data Control With Constant Delay and Application to Unmanned Ground Vehicles

In this paper, the synchronization issue for network systems with nonlinear dynamics is considered. Together with zero-order holder, the aperiodic sampled-data control law is utilized. Compared with the traditional periodic sampled-data control method, this approach demonstrates more greater flexibility. Adopting input delay approach, the initial sampled-data system is remodeled by continuous time system involving time-varying delays in the control signals. For the purpose of designing the sampling controllers suffering constant delays, an updated Lyapunov functional is developed from the augmentation of Wirtinger's inequality. Such a Lyapunov functional results in efficient and simplified synchronization conditions. A sufficient condition for synchronizability of network systems is set up. Then, for the case of unstable systems with some constant delays, a fresh discretized Lyapunov functional is introduced. Finally, we utilize the numerical simulation outcomes to prove the efficacy and advantage of our algorithm. Moreover, based on the network unmanned ground vehicle systems, the experiment results in a real scenario are provided to illustrate the effectiveness of the designed synchronization scheme.

Synchronization of Network Systems Subject to Nonlinear Dynamics and Actuators Saturation

This paper investigates the synchronization of network systems with time-varying delay, nonlinear dynamics and actuators saturation through the use of sampled-data controllers. Using tools from free-weighting matrix approach and Lyapunov stability theory, sufficient conditions for the synchronization of network systems are derived. It is theoretically shown that the synchronization of network systems can be achieved if the controller gain is selected suitably. Furthermore, the upper bound of sampling intervals for achieving synchronization is estimated via a simple algorithm. The effectiveness of the obtained results is verified through two numerical examples.

Delay-independent Synchronization in Networks of Time-delay Coupled Systems with Uncertainties

Abstract This paper investigates synchronization in networks of systems with transmission delay couplings. In our previous works, we have already clarified the relationship between graph topology and delay-independent synchronization occurring in networks of identical chaotic systems with transmission delays. In practical situations, however, each system in networks may have slight variations of parameters, and then the synchronization manifold may not exist unlike networks consisting of identical systems. Therefore, in this paper, we consider delay-independent practical synchronization conditions for such network systems. As a result, we conclude that delay-independent synchronization is structurally stable. Numerical simulations support the validity of the obtained results.

Delay-independent Synchronization in Ring Networks of Identical/Non-identical Systems with Transmission Delay Couplings

This paper investigates synchronization phenomena occurring in networks of chaotic systems with delays. In particular, we focus on delay-independent synchronization in ring networks of systems with transmission delays. First, we show that all the systems in ring networks consisting of an odd number of systems synchronize for any constant time-delay. Next, we also show that if the number of systems in ring networks is even, then partial synchronization can be observed regardless of the length of time-delay. In this case, full synchronization may also be observed as a special case of partial synchronization. In addition, we show that if two different dynamical systems are alternately arranged in even-sized ring networks, synchronization occurs among systems with the identical dynamics for any time-delay. Numerical examples show the validity of these theoretical results.

Global Synchronization of Directional Networked Systems With Eventually Dissipative Nodes

In the existing literature related to the global synchronization of networked systems, the V-uniformly decreasing condition on the nodal self-dynamics has often been assumed in advance. However this assumption excludes nonuniformly Lipschitz systems, such as the well-known Lorenz oscillators. In this paper, we adopt the eventual dissipativity condition to relax the V-uniformly decreasing condition such that the obtained results are applicable to some nonuniformly Lipschitz systems. Firstly the concept of synchronization degree is presented to depict the synchronizability of the nodal self-dynamics (NSD) system over its associated attractor. Then a virtual node whose trajectory is proved to ultimately evolve in the same region with that of isolated node is presented to play the reference trajectory. Next a simple global synchronization criterion that highlights the interplay between the NSD system and the network topology is presented, which can be applied for the reducible networks. Finally, a simulation example on a reducible network verifies the analytic results.