【作者】 丁飞；

【导师】 鲁照权；

【作者基本信息】 合肥工业大学 ， 控制理论与控制工程， 2010， 硕士

【摘要】 随着控制规模的日益扩大、计算机网络技术的飞速发展,基于计算机网络的控制系统已开始逐步应用到控制工程中。控制回路通过实施网络闭合的反馈控制系统称为网络化控制系统(Networked Control System,NCS)。网络化控制系统以其构建模块化,集成化,成本低等优点,一出现便受到了广泛的重视和研究,并且经过多年的发展,网络化控制系统研究已取得了长足的进步。但是,数据包的丢失和网络诱导时延的存在仍然是困扰系统性能和稳定性的最突出问题。本文综述了网络控制系统的概念及其结构,介绍了计算机网络的类型和特点,阐述了网络控制系统存在的主要问题以及目前针对这些问题的一些解决方法,研究了网络控制化控制系统的指数稳定和最大丢包率问题。对执行器节点和控制器节点采用事件驱动,对传感器节点采用时间驱动,基于异步动态系统理论对采样周期确定的具有数据传输成功事件与失败事件的异步动态系统进行了建模。利用Lyapunov理论和Schur补引理对网络控制闭环系统进行了稳定性分析。借助线性矩阵不等式,给出了能够使网络化控制系统稳定的充分条件。将马尔可夫跳变线性系统理论应用到网络化控制系统之中,将具有类似于伯努利分布的丢包情形的网络化控制系统理解为马尔可夫过程,而将丢包事件转化为马尔可夫过程中的可能状态。基于Schur补引理和马尔可夫链均方稳定判据,讨论了网络化控制系统的稳定性,给出了马尔可夫模型过程的网络化控制系统稳定的充分条件。为了便于研究网络化控制系统和检验研究结果,基于Matlab的TrueTime工具箱,对异步动态网络化控制系统进行了仿真研究。结果表明,在一定的丢包率范围内,异步动态网络化控制系统是稳定的。更多还原

【Abstract】 With control system scale growing and development of computer network technology, networked control system (NCS) has been gradually applied to control projects. In NCS, measure and control signals are sent by network. For a lot of advantages, as modular structure, low cost and so on, NCS has got much more attention and great development. However, problems, such as packet loss and network-induced delay, have not been solved. These problems will badly interfere NCS control performance and stability.In the dissertation, the concept and structure of NCS are introduced; the types and characteristics of computer networks are summarized; NCS main problems and some solutions are described; NCS exponential stability and patient packet loss rate are researched.In NCS, the actuator nodes and control nodes are to be driven by events and sensor nodes by time. Based on the dynamic system theory, a model is established for the determinate sample period dynamic system with success and failure events.NCS stability is analyzed by using the Lyapunov theory and schur complement lemma. The sufficient conditions for NCS stability is given based on the linear matrix inequality.Bernoulli distribution packet loss process is considered as Markov process. The packet loss events are taken into possible states in the Markov process.Based on the schur complement lemma and Markov chain mean-square stability criterion, the NCS stability is discussed, and the sufficient stability conditions is given for it.Simulations are done for the asynchronous dynamic NCS by TrueTime toolbox of the Matlab. The simulation results show that a system is still stable if the packet loss rate is in a certain range.更多还原