基于MAS和Petri-net技术的新能源电网协调控制策略

为提高新能源微电网电力供应的安全性和经济性,提出了一种基于Multi-Agent和Petri-net技术的协调控制策略。微电网是一个典型的混合系统,包括多种分布式发电和储能单元,它们具有不同行为特征和多种运行模态。考虑到这些分布式单元模态运行和逻辑切换的复杂性,构建了Multi-Agent系统(MAS),通过多Agent的交互作用来实现分布式协调控制策略。由于Petri-net模型是表述多模态运行系统的最有效工具之一,所以采用petr-net模型来描述各分布式单元的模态切换行为并以此设计其单元Agent模态切换控制策略。在此基础上,基于Multi-Agent系统框架在上层中心Agent中构建各分布式能源单元之间的模态协调切换控制策略,来实现整个微电网运行模态的有效切换。最后仿真验证了所提出的控制策略的有效性。     

Petri-net based modelling approach for ALFRED reactor operation and control system design

In this work, the Petri-net modelling approach applied to the control system design of the Advanced Lead Fast Reactor European Demonstrator (ALFRED) is presented, paying particular attention to the startup procedure. The reactor startup is the operational transient in which all the systems of the plant are brought from the cold shutdown condition to the full power mode, close to load-frequency control. In this phase, the several control actions to be taken need to be properly coordinated. To this end, the operational sequence which constitutes the reactor startup procedure has been described by adopting the Petri-nets approach, i.e., a useful formalism for the modelling and the analysis of Discrete Event Systems. Thanks to this quantitative representation, it is possible to easily derive the corresponding control scheme. In addition, the Petri-nets approach has been also exploited for the two-level control system architecture, namely a master system coordinates the operation of the plant by sending suitable signals to the slave system, in which feedback controllers are implemented. As a major outcome of this work, the procedure for the reactor startup and the transition to the full power mode has been simulated in order to assess the control system performance.     

基于时延库所Petri网的动态联盟任务调度研究

针对动态联盟中任务调度的特点,提出了采用时延库所Petri网对动态联盟任务调度进行建模。给出了模型的形式化描述及变迁规则,对动态联盟中的产品加工类型进行了分类,并建立了各种加工类型的时延库所Petri网模型,分析了通过模型中零时差的库所求解关键路径和利用可达图求解合理调度方案的方法。最后,以实例表明了该方法的可行性和有效性。     

一种基于Ontology的WEB服务时间约束定义及验证方法

针对目前面向服务计算(SCO)模式中组合Web服务验证缺乏对时间等非功能属性验证的实际,基于本体理论,设计并实现了一种基于时间约束Petri网的Web服务时间模型定义方法.该方法考虑服务流与以往工作流的区别,在服务模型OWL-S基础上建立时间本体(Time Ontology),全面地刻画了服务的基本时间约束.扩展已有的PetIi网本体,增强其描述能力,使其能够描述服务数据及时间信息,并定义了在OWL-S上定义的时间本体与Pe-tri网时间本体间的关系.根据模型检测理论,通过扩展OWL-API,将附加时间属性的OWL-S的服务描述本体转换为Petri网的标准格式PNML文件,建立起扩展时间属性的Web服务模型与形式化模型时间约束PetIi网(TCPN)间的映射关系.该方法很好地描述了服务时间约束,为后续的基于TCPN的服务时间形式化验证打下了坚定的基础.     

Automated guided vehicle systems and their Petri-net properties

This paper defines clearly and presents the fundamental properties of automated guided vehicle systems (AGVS) and their relationship to Petri nets. The objective is to develop an intelligent modelling tool to allow the design of robust AGVS models using some invariant Petri-net properties. The Petri-net properties of the system are presented in terms of safeness, boundedness, strict conservation, reachability and liveness. The robustness of the system at floor-level is embedded into the model by introducing system traffic collision-free, constant numbers of vehicles and traffic control signals, path reachability, and system traffic deadlock-free. Two different merge structures are presented to illustrate the effectiveness of the present approach. The result shows the strength of Petri-net theory in the modelling of complex AGVS. The AGVS models thus built are robust.     

基于Petri网的供需链设计优化研究

供需链设计优化问题由于其自身的复杂性而成为一个极具挑战性的研究课题。本文把Petri网与遗传算法结合起来，用于研究供需链设计优化，构建一个供需链原型测试系统，并对小汽车制造供需链系统进行了实例分析。     

The development of an AGVS model by the union of the modulised floor-path nets

The purpose of this paper is to propose an easy and quick method for the development of an automated guided vehicle system (AGVS) model. It suggests that the AGVS model can be developed directly by the union of modulised floor-path nets without any modification. Several modulised floor-path nets for both uni- and bi-directional systems are established in this paper. To make sure that the complete model obtained by this method is robust, the modulised floor-path nets are required to possess several essential properties — safeness, boundedness, conservation, reachability and liveness. To keep these properties in the complete model after the union, three union rules and an union procedure are proposed.     

Three solutions for a robot arm controller using Pascal-Plus,occam and edison

Three currently available concurrent language systems, Pascal-Plus, occam and Edison, are used to implement a controller for a robot arm. The robot arm allows real parallelism of operation within the movements of the arm. The feasibility and restrictions placed upon the resultant solution for each of the language systems is then analysed and discussed. A Petri-net solution is also presented for the generalized problem and it is shown that each of the solutions is a different folding of the general net.     

自动测试系统的随机Petri网模型及性能评价

提出了一种基于随机Petri网的自动测试系统建模方法,通过这种方法可以根据测试指标的要求生成最优的测试任务序列,节约测试时间,提高测试设备利用率,还可以预防自动测试系统出现死锁或资源冲突的情况.     

基于Petri网的工作流建模技术分析与应用

介绍了Petri网的基本知识,结合公文管理中收文、发文部分工作流应用环境,运用不变量的分析方法和工作流网的理论,提出了相对完整的基于Petri网的工作流模型,并对模型的可靠性进行了分析.