| The recent decade has witnessed the great development of researches on the study on complex networks. Diversity of the structure and the dynamical behaviors of complex networks make the research of them more meaningful and more challenging. The research on the synchronization has been an important object in control engineering field. Based on the former research, the thesis gives a survey of complex networks systems on the basis of related references and deals with some issues of synchronization control of complex networks systems on a theoretical and practical background. The main contents contain the following seven parts:1. From the new view of complex networks large-scale engineering systems are discussed. And the models of complex networks are built for these engineering systems. Then, the properties of the networks topology of the systems are analyzed based on complex networks theory. Combining the research of the synchronization of complex networks with large-scale engineering systems, we discuss the dynamical properties of the systems. So a novel way for solving this kind of problems for dealing with large-scale systems is presented.2. Focusing on star-shaped complex networks systems, conditions of achieving synchronization for this kind of systems are firstly discussed in the thesis. And it is found that the conditions are not related with the coupled strength of the networks. Then the concept of capable feedback synchronization (CFS) is presented. The problem of CFS of star-shaped complex networks is investigated and the criterion of CFS is obtained. Secondly, pinning control strategy is designed to make lower-order star-shaped complex networks systems synchronized based on the structural information of the networks. The strategies of global pinning control and local pinning control are presented in this thesis. At the same time, the pinning strategy of high-order star-shaped complex networks systems is also designed. Finally, concrete conclusions are arrived which are more suitable to the application.3. For the nearest-neighbor coupled complex networks systems, conditions of achieving synchronization for this kind of systems are firstly discussed in this thesis and it is found the system can achieve synchronization if the dynamics of nodes are stable. Based on the definition of CFS, the problem of CFS for this kind of systems is investigated. Secondly, the concept of attenuation rate of control ability is presented. The capacity of pinning control for the nearest-neighbor coupled complex networks systems is studied. In the following, the validity of different control strategies is compared in the given coupled complex networks. Finally, the strategies of global pinning control and local pinning control are achieved for this type of complex networks systems.4. The problems of synchronization and pinning control for general time-delay dynamical systems are investigated. In this thesis less conservative criterions of continuous-time complex dynamical systems with time-delay and discrete-time complex dynamical systems with time-delay are obtained. We apply pinning control strategies to a small fraction of nodes. Then the decentralized feedback controllers are respectively designed to make both continuous-time complex dynamical systems with time-delay and discrete-time complex dynamical systems with time-delay synchronized. At the same time, the stability of synchronization for the two kinds of systems is guaranteed. Moreover, the problems of designing controllers are converted into solving optimal problems of a series of linear matrix inequalities. The solution can be made use of available software, which reduces the complexity.5. Heterogeneous complex dynamical networks are investigated, in which the dynamics of nodes are different. Complex large scale systems possess the characteristics of high dimensionality, large number of variables and strong nonlinearity. One of the effective approaches for the complex system modeling is using one hybrid interconnected model to describe the dynamics of each subsystem. This thesis focuses on pinning control of a kind of heterogeneous complex network systems, whose dynamics of nodes described by different models. Through constructing a set of independent lower-dimensional linear matrix inequalities, and solving them in parallel, a novel stability analysis method is proposed. Thus the computational complexity is greatly reduced. Computer simulation is conducted to validate the effectiveness and efficiency of the proposed method.6. The problem of improving the consensus and synchronizability for weighted networks of dynamic systems via adding links among them is investigated in this paper. A weighted network entropy is introduced to measure the homogeneity of the weighted networks. The relationship between the homogeneity and the consensus and synchronizability is analyzed. A solution scheme is proposed to improve the consensus and synchronizability of the weighted networks through maximizing their homogeneity via adding as few links as possible. Weighted networks created from the Barrat model are tested by using the proposed scheme, and two commonly used link-adding approaches are selected to compare with this scheme. Computer simulation results show that the proposed link-adding scheme can enhance the consensus and the synchronizability of the weighted networks effectively and efficiently.7. Based on the theory of synchronization in complex networks, formation and tracking control of distributed multi mobile-robots are investigated under a changing external vector field. Each mobile robot measures the local value of the field along its trajectory and occasionally shares relevant information with other agents, in order to estimate the spatial average obtained from measurements across all mobile robots. Using shared information, mobile robots control their trajectories in a cooperative manner, with the goals of maintaining a desired formation about the average. Then two kind of communication networks including star-shaped networks and the nearest-neighbor networks formed between mobile robots is studied, based on which control strategies are given for mobile robots. Finally, applications of synchronization to mobile robots are further analyzed.
|
PDF Full Text Request