Cooperation of Multi-agent Systems

University of Technology Sydney. Faculty of Engineering and Information Technology.The cooperation of multi-agent systems represents that a group of agents complete the common tasks that are difficult or impossible for an individual agent or a single system to finish. The cooperation of multi-agent systems has received considerable attention and has been widely studied over the past few years. The consensus is the basis of the cooperation of multi-agent systems. Researching the cooperation of multi-agent systems probably involves a large number of theories, such as graph theories and stability theories of switched systems. In this thesis, we study consensus, tracking control, and containment control under a fixed graph. For a time-invariant network of multi-agent systems, its topological characteristic can be described by a fixed graph. For the time-variant network, we model the multi-agent systems by switched systems in this thesis and get some new conclusions. We transform the consensus problems into stability problems first and then get some new conclusions by the aid of conventional methods. For traditional approaches, there are many limitations. Many of the involved theories also need to be further improved. For example, the stability problems of switched systems have not yet been thoroughly resolved. Therefore, we also do much research work on stability analysis of switched systems. For switched systems, we propose some novel theories and methods to reduce the limitations of conventional stability analysis methods. We propose some sequence-based methods to resolve the stability problems and get some new results. It is proved that the switched systems are globally uniformly asymptotically stable when the sequence-based mode-dependence average dwell time satisfies the conditions deduced by this thesis. We use the proposed stability theories and methods to analyse the consensus of multi-agent systems under switched systems and get some new results. A proposed model transformation can transform consensus problems into stability problems. We get some novel results. In this thesis, we first introduce the background and then give a brief literature review on the stability analysis of switched systems and the cooperation of multi-agent systems. After that, Chapter 3 addresses multi-agent systems under a fixed topology. The research on the stability of switched systems is presented in Chapter 4. A consensus of second-order multi-agent systems under switched topologies based on the sequence is studied in Chapter 5. The research plan, progress, and our publications on this research topic are also shown in this report. Finally, we summarize my past work and give a conclusion