基于局域网多平台计算机视觉系统在柔性制造中的应用

设计了一套针对柔性制造系统（ＦＭＳ）的基于局域网络平台的计算机视觉系统，该系统采用了流行的ＴＣＰ／ＩＰ协议，使得一同操作系统中平以可以互操作，协作的完成柔性制造中的视觉伺服任务。     

柔性制造系统时延Petri网模型排产优化研究

为解决现有柔性制造系统排产效率低的问题，提出一种基于时延Petri网模型的柔性制造系统排产优化方法。首先，根据柔性制造系统生产模式的特点，为其建立包含生产路径约束信息的时延Petri网模型。其次，设计遗传算法与模拟退火算法的混合算法，快速搜寻时延Petri网模型最优或次优变迁发生序列，从而得到系统加工优化路径。最后，通过算例仿真与分析，表明该算法具有较高的准确率，且有较强的跳出陷阱能力，证明了其在基于时延Petri网模型的柔性制造系统排产优化方面的有效性。     

第五讲 提高柔性制造系统效益的措施

一、适用桑性制造系统的生产条件柔性制造系统并不是适用于所有情况的万能设备,它有一定的适用范围。也就是说,要想使柔性制造系统充分发挥作用,就应该在具有下列条件     

基于 Petri网的柔性制造系统动态优化模型

为解决柔性制造系统的动态优化调度问题,在基于扩展高级全局决策Petri网的柔性制造系统优化模型的基础上,提出了实时一优化切换控制Petri网模型。该模型在柔性制造系统发生加工设备故障、急件插入等异常情况时,自动切换并运行全局优化调度算法,并在系统允许的时间范围内,再切换返回到原有系统状态,按照新的优化结果运行。最后,以实时一优化切换控制Petri网模型与基于遗传的最小平衡算法结合为例,证实了该模型是有效的。     

柔性制造(FMS)加工系统机床选用浅析

柔性自动化制造技术迅速发展，其中柔性制造系统最具代表性，柔性制造系统中的加工系统是实际完成改变物性任务的执行系统，本文就加工系统中机床的选择进行了详细分析。     

基于代理的合弄控制系统的设计与开发

简要介绍了合弄制造系统及其框架结构,并对合弄制造系统的模块进行分析与设计,最后基于一个小型柔性制造系统,利用上述模型开发出合弄控制系统软件。     

基于产品数据管理技术的板材FMS后置集成研究

以板材加工柔性制造系统为对象，提出由设计向制造延伸的产品数据管理元结构模型。采用复合对象结构，能过对象内部具有不同类型的成员和成员之间的内在联系及对象之间的通讯，使得该模型不仅可将产品设计数据管理拓展到制造过程，而且可适合产品数据的动态过程管理。     

一种基于MBSE的柔性制造系统架构设计方法

根据军用产品的生产特点,为了提高军工产品生产控制的实时性和资源利用率,基于模型的系统工程方法,借鉴多代理技术,提出了一种柔性制造系统的架构设计方法。通过系统工程方法分析得出,在应用层与设备层之间增加计划调度代理、实时控制代理和设备控制代理的方式,可将柔性制造系统的各类信息进行实时交互和融合。相比于集中式的制造系统,在资源利用率和人工成本方面具有优势。最后,通过搭建基于多代理技术的柔性制造系统最小单元集,进一步验证了架构的有效性。     

基于分散搜索的零部件跨单元生产的单元管理方法

研究单元制造环境中零部件生产工艺不相同情况下零部件跨单元生产的单元管理问题。以最小化单元制造系统的流水时间为目标,对生产单元内设备上的零部件进行生产调度,提出该问题的非线性数学规划模型,开发针对该问题的分散搜索算法。该算法改进多样性产生器,使算法生成一系列多样性好的初始解,并针对该单元管理问题的特点,开发参考集更新方法、子集产生方法、子集合并方法和解改进方法等多种机制来实现对单元制造系统的有效管理。通过对多组单元管理实例进行仿真分析,与基准优化软件CPLEX相比较,验证模型与算法的有效性。     

遗传算法与模拟退火算法在FMS中的混合应用

讨论了柔性制造系统(FMS)中的机械加载问题,问题的主要目标是使制造系统不平衡最小化,在诸如可用的加工时间和刀具槽等工艺约束条件下使系统吞吐量最大化。将遗传算法(GA)与模拟退火(SA)算法相结合,提出了一种高效的进化算法——GASA。使用5个样本数据集对GASA的性能进行了测试,并与其他文献提及的启发式算法进行了比较,研究了它们对解决方案质量的影响。为了评价所提出的进化启发式算法的性能,通过进行大量的计算实验,以表格和图表形式给出了结果。实验结果表示GASA在柔性制造系统的应用中性能更好。     

The Application and Evaluation of Banker''s Algorithm for Deadlock-Free Buffer Space Allocation in Flexible Manufacturing Systems

Deadlock-free operation is essential for operating highly automated manufacturing systems. The seminal deadlock avoidance procedure, Banker's algorithm, was developed for computer operating systems, an environment where very little information regarding the future resource requirements of executing processes is known. Manufacturing researchers have tended to dismiss Banker's algorithm as too conservative in the manufacturing environment where future resource requirements are well defined by part routes. In this work, we investigate this issue by developing variants of Banker's algorithm applicable to buffer space allocation in flexible manufacturing. We show that these algorithms are not overly conservative and that, indeed, Banker's approach can provide very good operational flexibility when properly applied to the manufacturing environment.     

An algorithm for deadlock avoidance in an AGV System

In this paper, a simple and easily adaptable deadlock avoidance algorithm for an automated guided vehicle (AGV) system is presented. This algorithm uses the graph-theoretic approach. Unlike Petri-net-based methods, which are complex and static, it is easy to modify the existing model as the configuration of the system changes. Therefore, it is suitable for the AGV system in a flexible manufacturing system (FMS) and a retail or postal distribution center. Moreover, because it is very simple, it is appropriate for real-time control mechanisms.This paper consists of two parts: the first part presents an AGV deadlock avoidance algorithm that uses the graph-theoretic approach, and the second suggests appropriate routing strategies based on the proposed algorithm. The results show that this deadlock avoidance algorithm can be modified easily whenever the configuration of an FMS changes and provide high-performance on the deadlock avoidance. Finally, experimental results that confirm the validity of this approach are provided.     

An algorithm for deadlock avoidance in an AGV System

In this paper, a simple and easily adaptable deadlock avoidance algorithm for an automated guided vehicle (AGV) system is presented. This algorithm uses the graph-theoretic approach. Unlike Petri-net-based methods, which are complex and static, it is easy to modify the existing model as the configuration of the system changes. Therefore, it is suitable for the AGV system in a flexible manufacturing system (FMS) and a retail or postal distribution center. Moreover, because it is very simple, it is appropriate for real-time control mechanisms.This paper consists of two parts: the first part presents an AGV deadlock avoidance algorithm that uses the graph-theoretic approach, and the second suggests appropriate routing strategies based on the proposed algorithm. The results show that this deadlock avoidance algorithm can be modified easily whenever the configuration of an FMS changes and provide high-performance on the deadlock avoidance. Finally, experimental results that confirm the validity of this approach are provided.     

Application of Petri nets for deadlock analysis and avoidance in flexible manufacturing systems

Unreasonable dispatching resources to jobs in flexible manufacturing system (FMS) may result in a deadlock situation. This serious situation is studied and avoided through Petri net (PN) analysis techniques in this paper. Firstly, a production Petri net (PPN) model for a given FMS is developed. Based on a certain set of resources in PPN, the concepts of a deadlock state and a potential deadlock state are introduced. Then, we present a deadlock avoidance method that consists of two parts. One is the construction of a deadlock state equation that describes the intrinsic relationship between resources assignation and a deadlock state in PPN. This equation is a necessary and sufficient condition for the occurrence of a deadlock situation. The other is the construction of a restrictive PN controller for each deadlock state equation. This restrictive PN controller can control the resources dispatching by excluding some enabled transitions from firing, consequently avoiding the deadlock. This method is minimally restrictive and allows the maximal use of resources not only for normal FMS, but also for special FMS with cyclic deadlock structure chain (i.e., a pathological type of circular waiting structure). Finally, two applications are given to illustrate the validity of this method. The results show that this method can be efficiently implemented in practical FMS.     

FMS刀具流死锁控制策略与分派算法的研究

刀具流死锁控制及刀具分派问题是柔性制造系统(FMS)调度中的重要核心内容,为实现合理的死锁回避和刀具分派,在前期研究的基础上,通过建立刀具申请分配图,分析了死锁的相关性质,指出了FMS中刀具流死锁的两大根源是工件选择的不合理和刀具分派的不合理。提出了一种解决刀具流调度问题的两级死锁控制策略,建立了动态调度原理模型,给出了死锁检测算法和刀具分派算法。分析表明该策略与算法能够使得刀具流死锁的两大根源均得以回避,实现了刀具流死锁控制与刀具分派。     

FMS中资源共享导致的死锁状态及其避免方法

针对FMS中多种操作对有限资源的竞争会导致死锁状态，采用Petrinet分析技术对其进行了研究。建立了FMS的PPN模型，并在此基础上给出了直接死锁和潜在死锁的定义；引入了死锁状态方程的概念并给出了其构造方法；描述了死锁状态和资源分布之间的内在联系，并提出了一种死锁避免方法。实例表明该方法能够简单有效地避免死锁的产生，并允许资源的最大利用。     

平面包络环面蜗杆基于坐标测量的高精度制造方法

用坐标测量的方法实现了平面包络环面蜗杆齿形偏差的测量，提出了由齿形偏差的测量结果诊断蜗杆加工时机床工具的调整误差，并根据诊断结果修正机床工具的调整参数，从而提高蜗杆制造精度的方法，加工测量的试验表明本文方法十分有效。     

Deadlock control of flexible manufacturing systems via invariant–controlled elementary siphons of petri nets

Effective resolution for deadlock problems plays an important role in the operation of automated flexible manufacturing systems (FMS). Based on P-invariants and elementary siphons of Petri nets, a deadlock prevention policy is developed for a special class of Petri nets that can well model many FMS. Siphons in a plant net model are divided into elementary and dependent ones. For each elementary siphon, a monitor is added to the plant model such that the siphon is invariant-controlled. Our method guarantees that no emptiable control-induced siphon is generated due to the addition of the monitors. When all elementary siphons are controlled, the controllability of a dependent siphon is ensured by properly setting the control depth variables of its related elementary siphons. An FMS example is utilized to illustrate the proposed methods.     

An optimal-elementary-siphons-based iterative deadlock prevention policy for flexible manufacturing systems

Petri nets have been proved to be a tool with prominent capabilities to describe discrete event systems, such as flexible manufacturing systems (FMS), thanks to their excellent properties over other models. Characterization in terms of special structural elements in a Petri net called siphons has been a major approach for the investigation of deadlock-freeness in context of FMS. Utilizing the optimal elementary siphons and the modified mixed integer programming (MIP) algorithm proposed in this paper, one can detect and solve deadlock problems arising in FMS in an iterative mode with tractable computational complexity. Moreover, the MIP approach can be exploited to implement the flexibility enhancement in the resultant net system so that the obtained system is less restricted. In contrast to the conventional typical policies, this approach evolves without explicitly enumerating all the strict minimal siphons. Its legitimacy and feasibility are proved and validated through an experimental study.     

基于对象模型的FMS死锁检测

柔性制造系统的主要特点是多种不同类型的工件同时在系统中加工 ,这些工件竞争系统中的有限资源会导致死锁的发生 ,能够检查出 FMS运控软件中可能发生的死锁问题是系统能够正常运行的必要条件之一。本文首次基于面向对象模型 ,定义了死锁问题 ,并在此基础上提出了检测死锁的算法 ,此算法具有通用性和实用价值。