基于CSMA协议的无线网络控制系统的建模与优化

Wireless networked control systems (WNCS) are developing rapidly, in which the application of distributed CSMA protocol is becoming more and more popular. However, CSMA introduces the problem of system coupling, and the solution key is to coordinate protocol and control, which has become a novel and challenging issue. This research proposal focuses on the above coordination problem, and keeps its attention on the heterogeneous, asynchronous and dynamic properties of WNCS and also on the random and distributed nature of the CSMA protocol. Incorperating the LQG performance index and applying both theoretical and simulation/experimental methods, it digs into the CSMA capacity in delivering realtime control information, and proposes effective methods to optimize the system performances. Our main research contents include: establishing a mathematical model of the CSMA protocol based WNCS, and analyzing the impact of protocol parameters on the system performance; Determining the rational ranges of the protocol parameters that guarantee the system stability, setting up the joint optimization problem between LQG control and CSMA protocol, and proposing a centralized off-line optimization algorithm; In view of large-scale WNCS applications, studying the distributed channel quality assessment method, and proposing a distributed on-line coordination mechanism for the joint optimizaiton of control and protocol. The proposed research will not only promote the integration of networked control theories and wireless communication technologies, but also expand the scale and application areas of WNCS, and hence it has important theoretical as well as practical values.

随着无线网络控制系统的发展，具有分布式特点的CSMA协议在其中的应用将越来越广泛，由此引发了系统耦合问题，而解决的关键在于使协议与控制相协调，这已成为新的挑战性课题。本项目针对上述协调问题，紧扣无线网络控制系统的异构、异步和动态性以及CSMA协议的随机、分布式等特点，结合LQG性能指标，采用理论分析结合仿真实验的方法，深入挖掘CSMA协议进行实时控制信息传输的能力，提出有效方法来优化系统性能。主要研究内容有：建立基于CSMA协议的无线网络控制系统模型，研究协议参数对系统性能的影响；研究保系统稳定的协议参数范围，建立LQG控制与CSMA协议的协同优化问题，提出集中式离线逐步寻优算法；针对大规模应用，研究分布式的信道质量评估方法，提出协议与控制的分布式在线协调机制。本项目的研究有助于推动网络化控制理论与无线通信技术的进一步结合，延伸无线网络控制系统的应用领域，具有重要的理论意义和广泛的应用价值

随着无线网络控制系统的发展，具有分布式特点的CSMA 协议在其中的应用将越来越广泛，由此引发了系统耦合问题，而解决的关键在于使协议与控制相协调，这已成为新的挑战性课题。本项目针对上述协调问题，采用理论分析结合仿真实验的方法，深入研究了无线网络化控制系统的协同设计问题，取得了一系列研究成果。针对基于CSMA协议的无线网络化控制系统，提出了迭代型数学模型，并设计了一种结合CSMA和时槽分配的混合信道接入协议；针对多信道下的远程状态估计问题，提出了基于认知无线电技术的估计方法，给出了估计性能稳定的条件和估计误差的界，并对系统能耗进行了优化；针对无线网络化控制系统的协同设计问题，提出了集中式和分布式的节点调度、信道选择、传输调度、分布式控制等的优化方法。同时，针对无线网路控制系统安全这一新的研究领域，开展了不良节点检测和能量失效型攻击的监测与防御等方面的研究。项目取得的相关研究成果有助于推动网络化控制理论与无线通信技术的进一步结合。