共查询到19条相似文献,搜索用时 109 毫秒
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基于Petri网的智能制造系统建模 总被引:8,自引:1,他引:7
阐述了Petri网在智能制造系统建模中的突出优点,对其进行了扩展,并与面向对象技术相结合形成了面向对象Petri网(OOPN),提出了利用OOPN建立智能制造系统结构模型,行为模型,控制决策模型和消息模型的方法,通过利用OOPN建立智能制造中加工结点模型的实例,充分说明了面向对象Petri网的有效性和强大的建模能力,为智能制造系统的设计,性能分析,运行状态监视提供了一条有效途径和强有力的工具,必将在制造领域得到广泛应用和进一步的发展。 相似文献
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基于面向对象赋时Petri网的工作流建模方法 总被引:11,自引:0,他引:11
介绍了一般Petri网代数表示的基本定义,分析了赋时Petri网引入时间因素的两种方式。将面向对象建模技术融入到Petri网模型中,形成了面向对象赋时Petri网模型,讨论了建立基于面向对象赋时Petri网的工作流模型的步骤。最后运用面向对象赋时Petri网建立了某制造企业业务流程的工作流模型,并运用可达树分析方法分析了网模型的活性。 相似文献
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一种面向对象的Petri网及其应用研究 总被引:10,自引:0,他引:10
提出了一种面向对象的Petri网(OPN),较好地避免了一般Petri网建模时经常产生状态爆炸的问题,并具有较好的模块性、重用性及可维护性。通过利用OPN建立一个FMS模型的实例,说明了OPN的有效性和强大的建模能力。OPN为离散事件系统的建模提供了一种强有力的工具,具有良好的应用前景。 相似文献
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基于面向对象Petri网的多Agent系统交互协议建模 总被引:8,自引:0,他引:8
为了描述、分析和验证多Agent系统交互协议,提出了一种面向对象Petri网。与现有的形式化方法相比,面向对象Petri网能形象、直观地刻画多Agent系统复杂、并行的交互协议,可以描述其静态和动态语义,并可利用Petri网的数学分析方法对交互协议进行动态分析。面向对象Petri网还具有较好的模块性和柔性,能单独地分析参与交互的每一个Agent,而不会影响其他Agent和环境的状态。最后,利用面向对象Petri网描述了智能物理代理基金会请求协议和合同网协议,并对一个买卖Agent交互实例进行了建模和动态分析,验证了面向对象Petri网具有较好的建模能力。 相似文献
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并行工程是近年来国际制造业兴起的一种新型企业生产组织管理模式,也是当前学术界热门的研究课题。从并行工程运行模式出发,在Petri网基础上引入面向对象技术,针对并行工程的并发特性,讨论了基于并行工程的产品开发过程的面向对象Petri网模型,很好地继承了面向对象方法的封装、分类、继承等优点,同时又具有Petri网用图形易于描述系统并行性、不确定性等特征,为并行工程过程管理的仿真、调度和监控提供了统一模型。 相似文献
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分析了在递阶控制体系下FMS单元控制器的功能与结构。基于面向对象的思想,从设备层到工作站层再到单元层逐步扩展,建立了FMS的面向对象Petri网(OPN)动态模型,在此模型基础上,增加与系统调度和实际设备监控相关联的设备状态库所、控制库所和决策库所,使其扩展成为运控OPN。以运控OPN为核心并结合其他功能模块给出调度与控制集成的单元控制器软件结构,按照这种结构开发FMS单元控制器,并应用于北京交通大学教学型FMS。 相似文献
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分析了在递阶控制体系下FMS单元控制器的功能与结构。基于面向对象的思想,从设备层到工作站层再到单元层逐步扩展,建立了FMS的面向对象Petri网(OPN)动态模型,在此模型基础上,增加与系统调度和实际设备监控相关联的设备状态库所、控制库所和决策库所,使其扩展成为运控OPN。以运控OPN为核心并结合其他功能模块给出调度与控制集成的单元控制器软件结构,按照这种结构开发FMS单元控制器,并应用于北京交通大学教学型FMS。 相似文献
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介绍了面向对象Petri网理论并应用于固高公司小型柔性制造系统的建模中。该FMS的控制系统采用递阶控制体系结构,确定了模型转化成统一建模语言类结构图的规则,为柔性制造系统控制软件的开发提出了新的思路。 相似文献
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Improved net rewriting system-based approach to model reconfiguration of reconfigurable manufacturing systems 总被引:1,自引:1,他引:0
Jun Li Xianzhong Dai Zhengda Meng 《The International Journal of Advanced Manufacturing Technology》2008,37(11-12):1168-1189
This work aims at presenting a method for rapidly reconfiguring Petri net (PN) models of reconfigurable manufacturing systems (RMS). We start with introducing the model of improved net rewriting systems (INRS), which supports dynamic structural changes in a PN model without losing its important behavioral properties, i.e., liveness, boundedness (or safeness), and reversibility. Based on INRS, the method for rapid reconfiguration of Petri net models for RMS is proposed and an implementation algorithm is designed as well. In our method, changes in a RMS configuration adjusted with production demands can be rapidly formalized into graph rewriting rules of an INRS called model reconfigurator whose underlying Petri net is the existing Petri net model. Subsequently, by applying these rewriting rules, the existing Petri net model can be reconfigured rapidly into a new one for the RMS with a new configuration. Validity of the resulting Petri net model can be guaranteed naturally throughout the whole reconfiguration process and thereby there is no need for verification. A case study is provided that demonstrates the reconfiguration process of a Petri net model for a reconfigurable manufacturing cell. The given case study shows that the proposed method is capable for reconfiguring PN models of RMS in a rapid and successive manner, without requiring verification. 相似文献
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Construction and performance analysis of a Petri net model based on a functional model in a CIM system 总被引:1,自引:1,他引:0
Kichang Lee Hanil Jeong Chankwon Park Jinwoo Park 《The International Journal of Advanced Manufacturing Technology》2004,23(1-2):139-147
The so-called functional models, such as IDEF0, are useful tools for describing, designing and analysing the functional aspects of a complex manufacturing system, for example a CIM (computer integrated manufacturing) System. Though it involves considerable time and cost to build a sound functional model, the model usually cannot be used directly in further systems analysis procedures, such as quantitative performance analyses, due to its informal nature. To overcome this problem, we suggest a Petri net based procedure. First, we build a Petri net model from the IDEF0 and IDEF3 models, both of which are functional modelling tools widely used in real applications. Then, employing steady-state analysis for the Petri net, we propose a method to obtain performance measures such as the production rate. Since the analytical ability of a Petri net diminishes with increasing manufacturing system size, we develop a technique to aggregate and consolidate the Petri net to alleviate this problem that is associated with increasing complexity. An example problem is included to show the viability of our method for constructing a Petri net from a functional model and to evaluate the performance of the Petri net in an analytic manner. 相似文献
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《Computer Integrated Manufacturing Systems》1994,7(4):247-258
To maximize the productivity, quality and safety of operators, design and dependability analysis tools must be integrated as soon as possible in the lifecycle of automated manufacturing systems (AMS). As a concurrent approach, the structured analysis and design technique (SADT) can be efficiently used for such integration. SADT is a graphic notation for system specification and requirement analysis that is well adapted to describe the functions and their interconnection in a manufacturing systems. In spite of its advantages, SADT is limited by the lack of a formal foundation, which makes it necessary to extend it by a mathematical behavioural model such as the Petri net. This article first proposes an approach for the automatic generation of the Petri net model corresponding to SADT specifications, thus allowing a direct simulation of the SADT model to validate its behaviour. The complexity and non user-friendly interface of such a Petri net have led us to propose a temporal SADT whose primitives represent abstract types for the underlying Petri net model. This temporal SADT has the merits of both the SADT and Petri nets, since it adds to the user friendliness of SADT, the foundation of Petri nets. 相似文献
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介绍基于约束Petri网的规则集一致性检验命题的验证和实际应用,首先对约束Petri网的概念作了简要介绍。然后着重讲述应用面向对象方法开发的Petri网建模工具,以及一致性检验命题的软件实现方法,最后以某卫星电源系统为对象,对其故障诊断系统的知识库的一致性检验进行实际应用。 相似文献
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为解决一类具有多资源服务处理制造系统中的死锁问题,提出了利用Petri网描述系统结构和动态特征的方法,以及循环结构的新概念,证明了循环结构是导致系统死锁的惟一结构特征。利用辅助系统Petri网模型,提出了计算系统的所有基本极大循环结构的方法。对每个基本极大循环结构增加一个控制位置及其相关弧以限制其资源的利用,从而有效地避免系统死锁的发生。 相似文献
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介绍知识Petri网理论及其在系统建模中的优点,建立板材折弯FMC运行过程的知识Petri网模型,开发相应的FMC运行仿真软件。 相似文献
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Petri网在基于规则系统一致性问题检查中的应用 总被引:4,自引:1,他引:3
基于规则系统是目前应用较为广泛的一类专家系统,但它的知识库不易维护。本文针对基于规则系统的一致性问题,应用图形化建模工具Petri网的可达性概念和状态方程分析方法,提出了基于Petri网的一致性检查方法。文中首先对规则的三种Petri网表示模型进行了比较,并在含约束Petri网模型基础上,提出了一致性检验的命题方法,最后以实例说明该方法的实现步骤。当规则库较大时,相应的Petri网模型可能也会很庞 相似文献