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基于Petri网理论的动态系统可靠性建模方法研究 总被引:1,自引:0,他引:1
利用Petri网对动态系统的描述能力,将Petri网应用于机械系统可靠性分析领域。研究了基于Petri网理论的故障事件及其逻辑关系的表达方法,探讨了将Petri网应用于复杂动态系统可靠性建模的方法,给出了应用示例。 相似文献
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柔性制造系统是一个复杂的离散事件动态系统。在扩展高级决策:Petri网的基础上,提出了一种具有全局结构的扩展高级全局决策:Petri网,对柔性制造系统进行建模的方法。以扩展高级全局决策Petri网与基于遗传的最小平衡算法结合为例,证实了扩展高级全局决策:Petri网与智能优化方法相结合,既提高了FMS优化调度的整体性能,又使调度具有较强的可观性。 相似文献
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Petri网是研究离散事件动态系统的几种基本方法之一,己成功应用于生产制造系统及网络协议验证等领域。该文通过对自相似业务流的成因以及自相似性对网络性能的影响进行深入研究分析,然后根据网络数据传输过程的特点,建立随机Petri网模型,给出具有自相似特性的网络业务流传输过程的随机Petri网模型。使用Petri网建立了有限缓冲区的以太网模型,采用一种马尔可夫随机Petri网的方法对模型进行分析,最后利用随机Petri网性能分析工具SPNP对所建立的模型进行了模拟和验证,研究了自相似业务流对网络性能的影响。该文提出的模型在一定程度上能够很好地拟合不同网络的流量特性,为网络构建、网络特性分析和网络性能评估提供了重要的理论基础。 相似文献
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基于Petri网的生产系统仿真研究 总被引:2,自引:0,他引:2
以流水生产线为例,介绍了Petri网建模及其在制造系统中的性能分析。通过转换成马尔科夫链,可以计算变迁实施时间为指数分布的Petri模型的性能指标。并且针对Petri网模型计算复杂的特点,介绍了一种新的Petri网仿真方法——利用WITNESS软件对Petri模型进行仿真分析。 相似文献
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研究了基于含不可观变迁Petri网的码垛机器人零件加工系统故障检测问题。结合机器系统运行过程中的故障特征,对Petri网在机器系统故障诊断中的应用进行了研究,提出了包含不可观变迁Petri网的基本可达树和诊断分析函数的概念及基本可达树故障检测算法。以码垛机器人零件加工系统为例,建立了Petri网系统模型,应用基本可达树故障检测算法进行检测,故障检测结果符合码垛机器人零件加工系统实际运行情况,验证了该方法的有效性。 相似文献
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Petri网是一个描述条件和任务之间关系的通用模型。在介绍Web服务和Petri网的基础上,结合电力行业某业务流程管理系统的实例,建立了一个基于Petri网的业务流程模型,在此基础上对简化后的Petri网进行死锁分析,以此作为业务流程建模的指导思想,可以提高业务流程系统的安全性、稳定性、健壮性。 相似文献
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针对由Petri网建模的离散事件系统中具有混合约束的Petri网控制器的设计问题,利用局部设计和Petri网简化技术改进与完善控制器的设计方法,并证明所提方法是最大容许的.先利用局部设计Petri网简化技术把所有约束库所融合为一个与它们标识总量相等的库所,然后再与受约束的变迁进行对照比较,使控制器的设计更为简单并且避免了死锁,尤其是对规模较大的系统,其优势更加明显.针对于约束的不同情况,给出了相应的控制器设计方法,最后通过几个例子对该方法的简单性和有效性进行了验证. 相似文献
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基于TS算法的FPN鱼雷电子系统故障诊断方法 总被引:1,自引:0,他引:1
针对鱼雷电子系统故障传播的连续性,以及故障征兆与故障原因之间的模糊不确定性特点,提出一种基于禁忌搜索算法的模糊Petri网的鱼雷电子系统故障诊断方法.该方法定义了一个十元组的模糊Petri网,给出了表示模糊产生式规则的三种基本的模糊Petri网模型,在此基础上采用禁忌搜索算法对模糊Petri网模型参数进行优化.当模糊Petri网模型参数得到优化后,根据库所信度的大小通过故障推理进行故障定位.将其应用到某型鱼雷电子系统的故障诊断系统中,结果表明,该方法能够有效的提高模型故障诊断能力,具有较强的实用性. 相似文献
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晶圆加工过程中使用的模块化组合设备具有可重构性,设备配置的复杂程度由晶圆加工工艺方案决定,针对这一特点,研究了晶圆加工系统的Petri网建模问题。对晶圆加工模块化组合设备的加工流程进行了分析,给出了描述晶圆加工过程的时间Petri网模型。为避免Petri网模型随着设备复杂程度的增加而迅速膨胀,通过对系统运行特点的分析,建立了着色时间Petri网模型,网中节点数为常数值,与设备的复杂程度无关。从满足晶圆加工时间约束的角度,给出了带有时序控制器的着色时间Petri网模型,该模型有助于研究复杂制造系统的动态行为和生产过程控制。 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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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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Synthesis of feedback control elements for discrete event systems using Petri net models and theory of regions 总被引:2,自引:2,他引:2
M. Uzam 《The International Journal of Advanced Manufacturing Technology》2004,24(1-2):48-69
This paper describes a method for constructing a Petri-net-based controller for a discrete event system (DES) modelled by a Petri net. Assuming that an uncontrolled Petri net model of the DES and a set of forbidden state specifications are given, feedback control elements, i.e. a set of places and related transitions, with initial marking, are computed using the theory of regions, which is a formal synthesis technique for deriving Petri nets from automaton-based models. When feedback control elements are added to the uncontrolled Petri net model, the controlled (closed-loop) Petri net model of the system is obtained. The controlled Petri net model obtained is maximally permissive while guaranteeing that forbidden states do not occur. The proposed method is computationally efficient and does not suffer from the state explosion problem. Two examples are provided to show the applicability of the proposed method. 相似文献
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Zhenhua Wu Sheng-Jen Hsieh 《The International Journal of Advanced Manufacturing Technology》2012,61(1-4):405-421
In this paper, we explored a realtime fuzzy Petri net approach to diagnose progressive faults in discrete manufacturing systems. Progressive faults are usually caused by deterioration or aging and show stochastic properties. Some researchers have reported how to detect abrupt faults in discrete manufacturing systems using Petri net. However, little research has been conducted on Petri net diagnoser to progressive faults in discrete manufacturing event systems. To tackle this problem, we explored an approach including a realtime Petri net model and a fuzzy Petri net diagnoser to replicate the plant and detect faults in discrete manufacturing systems. The realtime Petri net model monitors events generated from the discrete manufacturing system, also compares the outputs and pre-settings. Once a difference is detected, it will start the fuzzy Petri net diagnoser to locate faults. For the purpose of validation, this approach was implemented with Visual Basic for diagnosing a dual robot arm. Evaluation experiments validated the diagnoser's performance on accuracy and diagnosability. It illustrated that the proposed approach can have a high accuracy rate of 93% and maximum diagnosis delay of eight steps; it proves that the approach has the capability of integrating knowledge and handling uncertainties. It also remedies the nonsynchronization between the diagnoser and the plant. The approach to construct the model and diagnoser is systematic; it has an excellent projection on intermittent fault diagnosis and hybrid systems. 相似文献