共查询到16条相似文献,搜索用时 62 毫秒
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针对面向半导体生产的重调度策略,在分析比较了已有的周期性重调度策略、事件驱动型重调度策略和混合型重调度策略的基础上,提出了一种新的改进的混合重调度策略.该策略从两方面对现有的混合策略进行改进:一是综合考虑多种重调度因素对引发重调度的影响;二是加入最小重调度时间间隔约束,从而既能有效跟踪半导体生产系统多种扰动,又能控制计算量,以保证系统实时性.最后,以实例说明了所得出的改进的混合重调度策略的应用. 相似文献
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为解决半导体生产线设备故障预测问题,采用自适应神经模糊推理系统构建故障预测模型.利用减法聚类确定模型初始结构,采用由最小二乘算法和梯度下降法所组成的混合学习算法优化模型参数.经实验数据检验,所建模型拟合能力强且精度高,能有效预测生产线下一阶段可能发生故障的设备名称等调度问题关键参数信息.在原有设备维护调度的基础上,嵌入故障预测模型,构建新的设备维护调度方案,并以某半导体生产线制造过程为例进行仿真验证,取得了良好的调度效果. 相似文献
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基于Petri网的敏捷化生产调度建模方法 总被引:1,自引:0,他引:1
针对企业生产调度敏捷化程度不高、影响整个生产系统产能和效益最大化的问题,结合Petri网技术、面向对象方法和敏捷制造思想,提出了基于Petri网的敏捷化生产调度建模方法,开发了敏捷化生产调度建模的调度流程,研究得出了扩展的产能计算函数,建立了以产能瓶颈站点为调度核心,并向其他次产能瓶颈站点发散的敏捷化生产调度模型,直观、形象地反映了企业生产实时调度情况。通过实证研究,构建了产能函数,实现了对整个生产系统的全面调度,提升了瓶颈站点的产能,缩短了产品生产周期,提高了整个制造系统的效益。 相似文献
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基于群体智能思想,提出了全局修正式半导体生产线重调度方法。首先,给出了基于群体智能思想的重调度模型;然后,在此模型基础上,给出了全局修正式重调度算法;最后,基于实际生产线的仿真模型对全局修正式重调度算法与企业原有算法进行了对比分析。仿真结果表明,在不确定的半导体生产线环境下,在适当的时候使用全局修正式重调度算法生成重调度方案,能够更好地优化模型的在制品移动次数、在制品移动速率与工件操作准时交货率等短期性能指标。目前,该方法已在某实际半导体生产线中应用并取得了良好的效果。 相似文献
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一类规则调度系统的Petri网研究方法 总被引:1,自引:0,他引:1
研究了规则调度系统的性能分析问题,与传统的仿真研究方法比较,文中采用了基于Petri网的研究思想,首先运用Petri网给规则调度系统建模,得到调度规则的形式化表示;然后基于该模型作稳定性及其它性能分析,最后针对一类切换式规则调度系统,介绍了运用混合动态系统理论开展研究的具体思路。 相似文献
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James T. Lin Chia-Chu Lee 《The International Journal of Advanced Manufacturing Technology》1994,9(4):271-280
Timed Petri-net (TPN) models were developed for evaluating the performance of robot-centred manufacturing cells (RMCs) by analysing interactions between the robot and workstations in the cells. The performance measures evaluated were average resource utilisations, average queue lengths, and average production rates. RMCs have been classified for the purpose of modularity into three types: parallel-type, flow-type and multiproduct-type. Amodular approach which facilitates an easy model construction was used for constructing TPN models for these types of RMCs. Structural analysis ensured that parallel-type and flow-type RMCs possessed properties of boundedness (finite states) and liveness (recurrence) both of which would guarantee that the equivalent Markov chain is ergodic, that is, the limiting probabilities exist. Liveness of multiproduct-type RMC, however, cannot be ensured since deadlock could exist in such a cell. This situation is discussed.Generalized timed Petri-net analyser (GTPNA) was used to support the evaluation of the TPN models obtained. 相似文献
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模糊柔性制造系统的混杂Petri网建模与调度 总被引:2,自引:0,他引:2
对模糊柔性制造系统的建模和调度进行了研究.定义了一种具有模糊区间速率的混杂Petri网模型,提出了模型的迁移使能和迁移引发语义,定义了弱使能迁移的模糊使能规则,给出了模型动态演变算法.建立了模糊柔性制造系统调度的模糊线性规划模型,并对典型的工业实例进行了分析.研究结果表明,基于所定义的混杂Petri模型能够有效地描述和分析模糊柔性制造系统. 相似文献
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L. Ferrarini M. Maroni 《The International Journal of Advanced Manufacturing Technology》1998,14(10):729-736
This paper addresses the problem of designing a control scheme capable of avoiding deadlock conditions for a class of manufacturing systems. The considered model for the system under control is based on Petri nets, and is formulated according to well-known modelling rules. A deadlock avoidance policy is proposed which is an extension of a previously presented one. The proofs of its main properties are briefly sketched. Finally, an example of an automated manufacturing system for which such a deadlock avoidance policy has been applied is discussed. 相似文献
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Tarek Y. ElMekkawy Hoda A. ElMaraghy 《The International Journal of Advanced Manufacturing Technology》2003,22(3-4):259-270
The dynamic nature of manufacturing makes rescheduling essential in today's complex production environment, particularly in flexible and re-configurable systems. Research on optimising schedules, which includes deadlock avoidance, is rather limited. Furthermore, the deadlock problem is mostly ignored in research on rescheduling. A rescheduling algorithm, that uses time petri-nets and the minimal siphons concept, was developed to deal with sources of disturbance such as machine breakdowns in real-time. The algorithm guarantees a deadlock-free new schedule. The existence of alternative routes, availability of material handling facilities and the limitation of buffer capacities were taken into consideration. The developed algorithm modifies only the affected portion of the original schedule, rather than rescheduling all jobs, in order to limit changes to the original schedule and reduce the impact on the response time.The effect of flexible routing, machine breakdowns, machine downtime, routing criterion and the use of the dispatching rule on the performance of manufacturing systems was studied. The systems performance was measured by the average flow time, the makespan and the average machine utilisation. The results indicate that utilising the system routing flexibility in real-time rescheduling, while avoiding deadlocks, improves system performance. Moreover, routing the interrupted operation to an alternative machine, based on the minimum expected completion time rather than the least utilised machine criterion, resulted in better performance. 相似文献
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为减少机床制造业在制造过程中的碳排放,对机床制造过程的碳排放边界进行界定,并对机床制造过程碳排放特性进行分析;基于Petri网建立了机床制造过程碳排放模型,并提出机床制造过程碳排放动态量化方法。将上述理论研究应用到某企业的机床制造过程中,得到其机床制造过程碳排放量情况,并据此提出了节能减排的措施建议。 相似文献