【作者】 杨业；

【导师】 王永骥；

【作者基本信息】 华中科技大学 ， 控制理论与控制工程， 2006， 博士

【摘要】 随着计算机网络技术、嵌入式系统的发展成熟,加之低廉的硬件价格,使得基于网络环境的自动化控制系统成为一种的新的应用趋势;在远程控制和复杂控制系统的客观需求下,网络控制系统的分析与综合迅速成为当前控制理论的研究热点之一;本文基于鲁棒控制理论、随机控制理论,切换系统理论、时滞系统理论、以及线性矩阵不等式方法,对线性系统、不确定系统、非线性系统的网络化控制问题、以及网络控制系统的实际应用进行了深入地研究,主要包括以下内容:对当前网络控制系统的发展以及国内外研究进展进行了概述,对网络控制系统的研究方法进行了详细的综合分析和总结;为了对网络控制系统的建模、设计提供有理的依据,本文对几种网络媒介的传输特性、网络延时特性进行了分析和总结;测试了Internet的通信延时,提出了基于支持向量机(SVM)的网络延时预测方法,对于基于Internet网络控制系统的研究具有重要的指导意义。针对一类由于节点间的竞争而导致访问滞后的网络化控制系统,本文通过等价变换,将网络控制系统建模为时滞系统,然后采用时滞系统的最新研究方法-奇异系统方法-来研究,得出了网络控制系统渐近稳定且时滞相关的充分条件。该结论具有较小的保守性,能够应用于网络控制系统的工程设计。针对一类具有长随机时滞特性的网络化线性控制系统,分别对状态反馈和输出反馈的情况,提出了基于对象模型的多步预测实现时滞补偿控制的策略;并分析了采用时滞补偿策略网络控制系统的稳定性,得出了保证网络控制系统稳定的充分条件。进一步,将该时滞补偿策略推广到不确定系统的网络化控制中,基于鲁棒控制理论和线性矩阵不等式方法导出了其稳定充分条件。研究了一类多包传输网络控制系统的建模与稳定问题;根据现场总线网络的传输特性,提出了一种合适的建模和设计方法,即:传感器节点和控制器节点以时间驱动方式工作,将多包传输网络控制系统建模为切换控制系统,最后分析了其稳定性,得出了渐近稳定的充分条件。针对一类单输入-单输出仿射非线性系统,首先通过微分同胚变换实现了仿射非线性系统的无反馈精确线性化;然后基于精确化线性模型,分别讨论网络延时为常时滞,随机时滞小于一个采样周期和随机长时滞情况的控制问题。通过一个具体的实例,给出了其设计方法与步骤。研究了基于Internet的网络控制系统的实现、控制问题。基于Socket通信技术,采用LabWindows/CVI 8.0开发了Internet环境下的液位过程控制系统。利用该网络控制系统实验平台,实现了校园网环境下液位过程控制系统的实时控制;采用时滞补偿策略,实现了Internet(广域网)环境下的液位过程控制系统。最后对全文进行了总结,指出了下一步需要研究的工作,对网络控制系统的未来进行了展望。更多还原

【Abstract】 As the development of network technology and embedded system, together with low-cost hardware, the network based automatic control system are becoming a new application trend. Driven by the external requirement of remote control and complex control system, the analysis and synthesis of networked control system becomes one of hot research fields of control theory. The networked control of linear system, uncertain system and nonlinear system and their applications are throughly studied in this thesis by applying the robust control theory, stochastic control theory, switched control theory, time-delay system theory, and the method of linear matrix inequality. The main contents are as follows:The development and current evolvement of networked control system are summarized, and the research methods of NCS are synthetically analyzed and summarized. In order to make the modeling and design of NCS more reasonable, the transmission characteristic and delays of a few networks are analyzed and summarized in this thesis. In addition, the transmission delays of the internet are tested, and the prediction method for transmission delays by Support Vector Machine is put forward, which is important guidance for development of internet-based control system.Aiming at a class of NCS with access delay because of competition of node, the NCS is modeled as time-delay system through equivalent transformation. By applying the newest research method of time-delay, i.e. singular system method, the delay-dependent stability results which are sufficient are derived. The theorem is less conservative, and can be applied to design NCS.A class of NCS with long and stochastic delays is studied. A multi-step prediction of based on plant model is put forward to implement the compensation control for the delays respectively for the cases of state and output feedback control. In addition, the stability of NCS with compensation is analyzed, and a sufficient condition is derived. Furthermore, the compensation method is extended to the networked control of uncertain system and the sufficient condition is derived by robust control theory and LMI.The modeling and stability of NCS with multiple-packet transmission are investigated. A suitable modeling and design method is brought forward according to the transmission characteristic of fieldbus, that is the controller and the actuator are time-driven. Therefore, the NCS are modeled as switched control system, and so a sufficient stability condition is obtained.A class of affine nonlinear system of single input-single output is investigated. Firstly, the nonlinear system is transformed into an equivalent linear system through a diffeomorphism transformation. The networked control problems for the delays are constant, stochastic and shorter than a sampling period, and long and stochastic are investigated respectively. Last, the material design method and approach are presented through an example.The implementation and control of internet-based control system are considered. The internet-based level process control system is developed by applying LabWindows software and socket communication technology. The realtime control of campus network based level system is realized on the developed NCS platform. In addition, a wide area internet-based level system is also realized by using the prediction compensation method.Last, the summary of the thesis, the future work to be investigated, and the prospect of NCS are presented.更多还原