【作者】 鲁立；

【导师】 褚健； 冯冬芹；

【作者基本信息】 浙江大学 ， 控制科学与工程， 2013， 博士

【摘要】 随着工业信息化与自动化的不断融合,石油、化工、能源、冶金、制药、交通、船舶、装备制造等系统规模越大越大,复杂度越来越高,需要传输的业务信息量也越来越多。其中可能既含有传统的低速流程控制业务,又有高速强实时运动控制业务,甚至还有故障恢复检测等业务。这种应用特征对网络通信系统信息传输的实时性、稳定性、可靠性提出了严峻的要求。在传统工业网络中,对业务特性要求不同的控制系统通常被分隔为若干个互不相关的业务子系统,并加以独立的分析和研究。这些相互独立的网络系统构成了一个个“信息化孤岛”,导致工业实时应用中的信息集成、互访问和互操作困难,实时性也得不到良好保证。为此,迫切需要将工业实时应用中的各种信息传输融合集成到同一个网络系统中,以实现一个不同信息流能够实时互访与融合的多业务实时网络。然而,目前学术界的研究基本仅限于单一业务的工业以太网,很少有多业务工业网络的相关成果。而在实际应用中,现阶段也没有一个实质性的多业务网络解决方案。因此研究工业多业务流实时网络的建模与优化策略不论在理论上还是在应用上都显得格外迫切。本文在综述了不同业务流的工业实时以太网模型以及相关的调度和优化策略的国内外研究现状后,首次提出和定义了工业多业务实时网络的概念,将多业务流分类归纳为RT, FRT,以及DR等三种业务。以中国自主制定的工业自动化领域的第一个国际标准EPA为基础,研究了多业务流的分类与建模,工业实时以太网通信模型,强实时业务的调度与优化,控制回路在工业实时网络中的稳定性,故障检测恢复业务建模与自愈时间分析,以及多业务流融合网络构架与调度策略。所做的具体研究工作包括：1.以EPA网络为基础,定量划分了RT,FRT和DR三种业务的区间。分析了工业实时以太网的通信调度机理。针对现有EPA相关研究中缺乏定量理论模型的问题,通过对基于角色平等的分布式协议机理的分析,建立了相关的数据模型、调度模型、时间模型,给出了调度规划算法及可调度性判断依据。2.针对面向传统流程工业而制定的原版EPA协议的一些不足,提出了若干改进实时性并增强FRT业务性能的方案。在通信机理,同步方法,网段划分,静态时间窗口调度等方面提出了优化策略。提出了一种多网段矩形阵列拓扑结构和相应的时间片规划方案。3.分析了报文传输时延和时钟同步精度对EPA网络控制系统实时性和稳定性的影响,提出了新的基于马尔科夫链的时延模型。分析了系统稳定时通信宏周期、协议传输时延和时钟同步精度应满足的条件。建立了EPA网络控制系统模型。给出了EPA控制系统稳定时可以设置的最小通信宏周期的计算方法。4.针对以往故障检测和恢复业务没有考虑到现有实时业务的问题,在原有DRP协议基础上提出了全新的DR业务。基于网络演算理论,给出了恢复时间和带宽占用率模型。对整合了实时业务和DR业务的分布式冗余网络进行了性能分析,给出了优化方案。5.提出了一种多业务流融合网络的整体框架与解决方案。给出了一种基于广义宏周期的业务融合策略与动态宏周期调度算法。建立了多业务流网络中的宏观数据模型,流量模型以及有效网络利用率模型。针对业务流实时性需求的差异提出了多层子网结构,给出了相应的数据聚合方法和调度策略,并研究了基于最优树概念的多层子网结构最优拓扑以及时间片规划问题。更多还原

【Abstract】 With the increasing integration of informatization and automation in industries like petroleum, chemical, energy, metallurgy, pharmacy, transportation, shipbuilding and manufacturing, we are now building systems with larger scale and higher complexity wherein more service data needs to be transmitted. Among those services there may exist traditional low-speed process control services, high-speed motion control services or even fault detection and recovery services. The challenges to real-time, stability and reliability of communication networks are becoming more and more severe. In traditional industry network systems, different services are usually transmitted in separated networks, and the research on them are also independent. These independent networks lead to information islands that have become a major obstacle to information integration. The real-time requirements of the network are also hard to be satisfied. As a result, it is important to integrate all these services into a single network to form a multi-service real-time network that ensures mutual access, interoperability and information fusion.However, most of the existing researches are restricted to single-service industrial Ethernet. There are few works on multi-service industrial networks and no substantial application solution is presented either. A research on this topic is thereotically important and practically urgent.After a thorough review of researches on RTE (Real-Time Ethernet) modeling, scheduling and optimization for different industrial services, this paper defines a new conception of industrial multi-service real-time network for the first time. The services are divided into three categories named RT (Real-Time), FRT(Fast Real-Time) and DR (Distributed Redundancy) services. Based on the real-time protocol EPA (Ethernet for Plant Automation) proposed by China, this paper studies the classification and modeling of services, the communication model of RTE, the scheduling and optimization of FRT services, the stability of control loops in RTE, the modeling of DR services with an analysis of recovery times, and the structure of the multi-service fusion network with a scheduling scheme. Specific results can be summarized as follows:1. The categories of RT, FRT and DR services are established based on EPA. The scheduling mechanism of EPA networks is analyzed. As a first attempt to quantitatively model EPA, the data, scheduling and timing models are built based on a comprehensive analysis of the distributed EPA protocol. The scheduling algorithm and criterion of schedulability of EPA networks are given.2. Some shortcomings inherent in legacy EPA protocol are analyzed and modifications are made to improve the real-time performance of EPA networks in FRT scenarios. Optimization schemes for communication process, synchronization, network segmentation and static time window allocation are proposed. A multi-segmented matrix network structure with a set of scheduling rules is presented.3. A new model of Markovian jump discrete-time networked control systems (NCS) is proposed based on the analysis of the influences that the packet transmission delay and the precision of clock synchronization exert on EPA control systems. The system stability conditions that must be satisfied by the transmission delay and the precision of clock synchronization are studied. An NCS based on EPA is modeled. An algorithm is proposed to obtain the shortest communication macrocycle for an EPA system to be stable.4. The original DRP (Distributed Redundancy Protocol) is modified and a new DR service is defined to accommodate the RT service which is not allowed for in existing researches. The recovery time and service occupancy rate models are given based on the network calculus. The performance of DRP is studied while the RT service is considered. The optimization scheme of DRP is proposed.5. A network structure of the multi-service fusion network is proposed. A service fusion scheme and a dynamic macrocycle scheduling algorithm are given. The models of data, flow and effective bandwidth utilization are developed for the multi-service network. A multi-level network structure is proposed according to different real-time requirements of the services. A data aggregation policy, a scheduling scheme and a conception of optimal tree are proposed to solve the problems of network structure optimization and timeslot allocation in the multi-level network.更多还原