Feedback control design for the complete synchronisation of two coupled Boolean networks

In the literatures, to design state feedback controllers to make the response Boolean network synchronise with the drive Boolean network is rarely considered. Motivated by this, feedback control design for the complete synchronisation of two coupled Boolean networks is investigated in this paper. A necessary condition for the existence of a state feedback controller achieving the complete synchronisation is established first. Then, based on the necessary condition, the feedback control law is proposed. Finally, an example is worked out to illustrate the proposed design procedure.     

Distributed control of cluster synchronisation in networks with randomly occurring non-linearities

This paper is concerned with the issue of mean square cluster synchronisation in complex networks, which consist of non-identical nodes with randomly occurring non-linearities. In order to guarantee synchronisation, distributed controllers depending on the information from the neighbours in the same cluster are applied to each node, meanwhile, the control gains are supposed to be updated according to the given laws. Based on the Lyapunov stability theory, the sufficient synchronisation conditions are derived and proved theoretically. Finally, a numerical example is presented to demonstrate the effectiveness of the results.     

Adaptive fixed-time control for cluster synchronisation of coupled complex networks with uncertain disturbances

This paper focuses on the cluster synchronisation problem of coupled complex networks with uncertain disturbances under an adaptive fixed-time control strategy. To begin with, complex dynamical networks with community structure which are subject to uncertain disturbances are taken into account. Then, a novel adaptive control strategy combined with fixed-time techniques is proposed to guarantee the nodes in the communities to desired states in a settling time. In addition, the stability of complex error systems is theoretically proved based on Lyapunov stability theorem. At last, two examples are presented to verify the effectiveness of the proposed adaptive fixed-time control.     

Guaranteed cost control of synchronisation for uncertain complex delayed networks

In this article, the synchronisation for a class of complex delayed dynamical networks with uncertain inner coupling configuration is investigated under the quadratic guaranteed cost control. The coupling delay and nodes delay are considered in the networks. Based on Lyapunov–Krasovskii stability theory, sufficient conditions for the existence of the optimal guaranteed cost control laws are given in terms of linear matrix inequalities. Under these sufficient conditions, the networks are globally asymptotically synchronous, and the optimal upper bound is also guaranteed. Numerical examples are given to illustrate the effectiveness of the proposed methods.     

Passivity and synchronisation of complex dynamical networks with multiple derivative couplings

Two network models with multiple derivative couplings and different dimensions of output and input vectors are investigated in this paper. The problem of passivity for the proposed network models is analysed by utilising some inequality techniques and Lyapunov functional method, and several synchronisation conditions for complex dynamical networks with multiple derivative couplings (CDNMDC) are given. Moreover, by employing adaptive state feedback control strategy, some sufficient conditions for guaranteeing passivity and synchronisation of CDNMDC are obtained. In the end, we give two examples to verify the effectiveness of the results.     

Non-fragile synchronisation of mixed delayed neural networks with randomly occurring controller gain fluctuations

This study is concerned with the problem of non fragile synchronisation of mixed delayed neural networks with randomly occurring controller gain fluctuations. By using a novel mathematical approach and considering the neuron activation functions, improved delay-dependent stability results are formulated in terms of linear matrix inequalities (LMIs). An augmented new Lyapunov-Krasovskii functional (LKF) that contains double and triple integral terms is constructed to ensure the asymptotic stability of the error system which guarantees the master system synchronise with the slave system. Finally, numerical examples are provided to show the effectiveness of the proposed theoretical results.     

Impulsive synchronisation of singular hybrid coupled networks with time-varying nonlinear perturbation

The impulsive synchronisation of singular hybrid coupled systems with time-varying nonlinear perturbation is discussed in this paper. The synchronising impulsive effects are considered for singular hybrid coupled systems. A sufficient condition that ensures the synchronisation of singular impulsive dynamical networks is derived by applying a single pinning impulsive controller. Moreover, the convergence rate of the stability is estimated for the discussed dynamical network. Finally, simulation result is given to illustrate the effectiveness of the developed criteria.     

Stochastic mean square exponential synchronisation of time-varying complex dynamical networks via pinning control

This paper investigates the problem of stochastic mean square exponential synchronisation of complex dynamical networks with time-varying delay via pinning control. By applying the Lyapunov method and stochastic analysis, criteria on mean square exponential synchronisation are established under linear feedback pinning control and adaptive feedback pinning control, which depend on the time-varying delay and stochastic perturbation. These results complement and improve the previously known results. Two numerical examples are given to illustrate the effectiveness and correctness of the derived theoretical results.     

Cooperative output synchronisation of networked feedforward nonlinear systems via linear sampled-data control

This paper studies the problem of cooperative output synchronisation of networked feedforward nonlinear systems via linear sampled-data control. To dominate the unknown nonlinear perturbing terms, a scaling gain is introduced by a change in coordinates. Then, we construct a reduced-order sampled-data observer and use the backstepping method to design a linear sampled-data controller. By using combined graph theory with feedback domination approach, an explicit formula for the sampling period can be obtained under the proposed controller with appropriate gains such that all outputs of the agents in the network can be synchronised. Finally, two examples are provided to verify the effectiveness of the proposed method.     

A general approach for synchronisation of nonlinear networked systems with switching topology

This article investigates synchronisation of a nonlinear networked system with switching topology. By defining a common synchronisation manifold for each possible switching topology, exponential synchronisation of a nonlinear networked system can be assessed by the exponential stability of a reduced nonlinear system corresponding to the concerned system, wherein the communication graph can be directed and weighted and the inner-linking matrix might be singular. In particular, a synchronisation criterion consisting of the self-dynamics of isolated nodes and the consensus dynamics of a linear switched system is given. Two numerical simulations of synchronisation are presented to illustrate the effectiveness of the analytical results for the periodic and random switching cases.     

A method for designing the communication structure of networked controllers

The paper analyses the command-following behaviour of synchronised systems in dependence upon the communication structure of the networked controller. Its focus lies on the transient behaviour before the subsystems reach a common trajectory. It considers the dynamics of the subsystems as the main reason for the delay that the information about the reference trajectory is exposed to between the leader and the followers on a communication path, whereas the communication network is assumed to provide instantaneous information transmission. An abstract model of the overall system is introduced that represents the coupling structure of the agents together with a quantitative delay measure. This model is used to determine communication structures in which all agent outputs follow the reference trajectory with small delay. It helps to find a trade-off between the number of communication links and the quality of the system performance. The results are illustrated by its application to a robot formation problem.     

Extended-state-observer-based adaptive control for synchronisation of multi-agent systems with unknown nonlinearities

This paper studies the problem of synchronisation to a desired trajectory for non-linear multi-agent systems. By introducing extended state observer approach, decentralised adaptive controllers are designed for distributed systems which have non-identical unknown non-linear dynamics. The non-identical unknown non-linear dynamics allows for a tracked command dynamics which is also non-linear and unknown. State variables of agents can be obtained only in the case where leader agent and the network communication topology for multi-agent systems is strongly connected digraph network structures. A Lyapunov-function-based approach is given to show that the tracking error is ultimately bounded. Some simulation results are given to demonstrate the effectiveness of the developed techniques in this paper.     

Cluster synchronisation of directed complex dynamical networks with nonidentical nodes via pinning control

In this article, we study the cluster synchronisation problem of directed complex dynamical networks through controlling some specific nodes. This method explains which nodes should be chosen as pinned candidates. Owing to the special structure of cluster network, the number of such nodes is extremely small. In our model, we consider a directed network whose nodes in different clusters are nonidentical. Then some sufficient conditions to guarantee cluster synchronisation in the coupled network are presented. Finally, numerical examples are given to verify our theoretical analysis.     

Improved results on synchronisation of Markovian jump complex dynamical networks via sampled-data controller and convex combination

This paper investigates the Markovian jump complex dynamical networks via a sampled-data controller and convex combination. Firstly, constructing an improved discontinuous Lyapunov-Krasovskii function (LKF), which is fully considered the characteristics of sampled-data to reduce the conservativeness. Secondly, designing an appropriate sample-data controller and combining some integral inequalities, convex function and free weighting matrices to utilise the upper bound on variable sampling interval and the sawtooth structure information of varying input delay. Then one can obtain the new criterion of sampled-data synchronisation. Finally, giving two examples to prove the effectiveness and superiority of the proposed methods. Obviously, compared with other existing literatures, this paper has less conservative.     

Backstepping-based synchronisation of uncertain networked Lagrangian systems

In this article, we study the synchronisation problem of uncertain networked Lagrangian systems on directed communication topologies. For the nominal model without uncertainties, we propose a backstepping-based synchronisation design for heterogenous Lagrangian systems on directed graphs with a spanning tree. We relax earlier constraints on the feedback gain for the distributed synchronisation control law, which encompasses the existing double integrator consensus problem as a special case. We then extend the proposed design to the case without relative velocity measurement. For the uncertain Lagrangian model, we develop a distributed adaptive redesign so that asymptotic synchronisation convergence is achieved in the presence of linearly parameterised model uncertainties. Simulation results show the effectiveness of the proposed method.     

Finite-time synchronisation control of coupled reaction-diffusion systems

ABSTRACT

We consider the finite-time synchronisation for coupled reaction-diffusion systems. At first, we design a pinning control strategy for the coupled systems. For the uncontrolled nodes, we use the adaptive adjustment to the coupling strength. Based on the Poincaré inequality technique and using the finite-time stability lemma, we obtain the sufficient condition to ensure the finite-time synchronisation. Time delay occurs usually in the coupled systems and when there exist time-varying delays in the coupled reaction-diffusion systems, we design a controller to impel the coupled systems to achieve the finite-time synchronisation. Finally, numerical examples are given to illustrate our theoretical results.     

Explicit synchronisation of heterogeneous dynamics networks via three-layer communication framework

This paper addresses the explicit synchronisation of heterogeneous dynamics networks via three-layer communication framework. The main contribution is to propose an explicit synchronisation algorithm, in which the synchronisation errors of all the agents are decoupled. By constructing a three-layer node model, the proposed algorithm removes the assumptions that the topology is fixed and the synchronisation process is coupled. By introducing appropriate assumptions, the algorithm leads to a class of explicit synchronisation protocols based on the states of agents in different layers. It is proved in the sense of Lyapunov that, if the dwell time is larger than a threshold, the explicit synchronisation can be achieved for closed-loop heterogeneous dynamics networks under switching topologies. The results are further extended to the cases in which the switching topologies are only frequently but not always connected. Simulation results are presented with four single-link manipulators to verify the theoretical analysis.     

Global asymptotical synchronisation in linearly coupled networks of RCL-shunted Josephson junctions

This article presents the synchronisation criteria for a class of dynamical networks with each node being resistively-capacitively-inductively-shunted (RCL-shunted) Josephson junction, which guarantee the synchronised states to be global asymptotically stable. These conditions are established in terms of linear matrix inequalities (LMIs), readily solvable by available numerical software. In addition, an interesting conclusion is reached that the stability of synchronisation in the coupled whole 3N-dimensional networks can be converted into that of 3-dimensional space.     

Projective synchronisation of a new chaotic system via small-gain theorem

On the basis of the small-gain theorem, the projective synchronisation (PS) between two identical new chaotic systems is investigated. Moreover, the general sufficient conditions to achieve PS between the new chaotic system and the Lü chaotic system are obtained via the small-gain theorem. Numerical simulations are performed to verify and illustrate the analytical results.     

Passivity and robust synchronisation of switched interval coupled neural networks with time delay

This paper is concerned with passivity and robust synchronisation of switched coupled neural networks with uncertain parameters. First, the mathematical model of switched coupled neural networks with interval uncertain parameters is established, which consists of L modes and switches from one mode to another according to the switching rule. Second, by employing passivity theory and linear matrix inequality techniques, delay-independent and delay-dependent conditions are derived to guarantee the passivity of switched interval coupled neural networks. Moreover, based on the proposed passivity results, global synchronisation criteria can be obtained for switched coupled neural networks with or without uncertain parameters. Finally, an illustrative example is provided to demonstrate the effectiveness of the obtained results.