模具车间作业控制系统设计

车间作业控制是制造企业MRPⅡ／ERP系统的一个重要组成部分,是MRPⅡ／ERP计划的具体实施环节。以模具生产为例,阐述了一种车间作业控制系统的功能结构和设计方法。     

A multi-agent RFID-enabled distributed control system for a flexible manufacturing shop

Flexible manufacturing systems are complex, stochastic environments requiring the development of innovative, intelligent control architectures that support flexibility, agility, and reconfigurability. Distributed manufacturing control system addresses this challenge by introducing an adaptive production control approach supported by the presence of autonomous control units that are cooperating with each other. Most of the currently distributed control systems still suffer from lack of flexibility and agility when the product verity is high and is not reconfigured in case of ad hoc events. To overcome this limitation, a drawback of an excessive dependence on up-to-date information about the products and other elements that move within the system is essential. Radio frequency identification (RFID) is a new emerging technology which uses radio frequency waves to transfer data between a reader and movable item for identification, tracking, and categorization purpose. This paper discusses the architecture devised to deploy RFID-enabled distributed control and monitoring system by means of a set of agents that are responsible for the realization of different control and monitoring tasks and for cooperating to enhance agility, flexibility, and reconfigurability of manufacturing system.     

Coloured adaptive structured petri-net a tool for the automatic synthesis of hierarchical control of flexible manufacturing systems

Based on the authors' last results concerning a methodological approach for the analysis and the synthesis of flexible cells in manufacturing, this paper presents some basic ideas on which the authors are currently working for the automatic design of hierarchical control of flexible manufacturing systems (FMS). The approach is based both on the use of coloured adaptive structured Petri-nets (in order to describe the scheduling of manufacturing tasks) and artificial intelligence concepts to design such a net and to describe metarules for the control strategy. The paper is in two parts.     

Scheduling in aerospace composite manufacturing systems: a two-stage hybrid flow shop problem

This research investigates a real-world complex two-stage hybrid flow shop scheduling problem which is faced during the manufacturing of composite aerospace components. There are a number of new constraints to be taken into account in this special hybrid flow shop, in particular limited physical capacity of the intermediate buffer, limited waiting time between processing stages, and limited tools/molds used in both stages in each production cycle. We propose a discrete-time mixed integer linear programming model with an underlying branch and bound algorithm, to solve small- and medium-size problems (up to 100 jobs). To solve the large instances of the problem (up to 300 jobs), a genetic algorithm with a novel crossover operator is developed. A new heuristic method is introduced to generate the initial population of the genetic algorithm. The results show the high level of computational efficiency and accuracy of the proposed genetic algorithm when compared to the optimal solutions obtained from the mathematical model. The results also show that the proposed genetic algorithm outperforms the conventional dispatching rules (i.e., shortest processing time, earliest dues date and longest processing time) when applied to large-size problems. A real case study undertaken at one of the leading aerospace companies in Canada is used to formulate the model, collect data for the parameters of the model, and analyze the results.     

面向航空发动机装配车间知识化制造系统自进化

针对存在缺件情况的航空发动机装配车间,研究了知识化制造系统自进化问题。采用事件和周期混合驱动型自进化机制,结合滚动时域法实现车间自进化。基于生产特点提出一种滚动规则,用于各决策时刻选取工序进入滚动窗口,建立了每个决策时刻系统中静态决策问题的数学模型,并给出了自进化问题的求解算法。针对模型设计了一种遗传—变邻域搜索算法进行求解。通过仿真实例对算法的性能进行了分析。实验数据表明,自进化在提升系统生产性能方面发挥了重要的作用。     

Developing a computer control system for a flexible manufacturing cell

This article focuses on the development of a computer control system for a flexible manufacturing cell. The paper outlines the various modules that are required for a computer control system and elaborates on the development of some of these modules. This is part of an ongoing research project at the University of the Witwatersrand. The aim of the project is to demonstrate the viability of flexible manufacturing systems to South African industry. Thus the main constraints of the project were cost, ease of implementation, and ease of maintainability. This necessitated the use of existing machinery and of computer systems and software that were readily available and already familiar to industry.     

Web-based distributed manufacturing control systems

With the evolution of the application of web technology, agent-based manufacturing systems can be both easily implemented and become a potential approach for modern manufacturing enterprises. In this paper, we present problems and models required for the development of web-based distributed manufacturing control systems. The specific objectives are: (1) to propose an appropriate architecture for a web-based distributed manufacturing control system, (2) to define the specification of a web-based cell controller, (3) to design the co-operative mechanisms, contract net protocol, for better system performance, (4) to upgrade the communication capability of existing CNC machines from RS232C to TCP/IP (Transmission Control Protocol/Internet Protocol) based on Ethernet .To demonstrate the proposed development, prototype software based on ASP and VB programming was designed and implemented. As a result, not only is a great amount of time saved in the development of web-based manufacturing control software, but this development can also enhance the competitive capability of companies trying to operate on a flexible basis.     

机械制造企业车间制造过程信息集成方案研究

在综合分析制造执行系统(MES)技术发展的基础上,结合我国机械制造企业的具体情况,研究机械制造企业车间制造过程、主要功能和信息交换关系,提出通过车间制造过程集成企业的管理和技术系统,建立一种车间制造过程的集成方案,以满足企业的集成需求,并结合案例进行说明.     

Applying a software framework for supervisory control of a PLC-based flexible manufacturing systems

In this paper, a software framework for a distributed flexible manufacturing system is presented where, as a main design goal, we consider that the functionalities are offered to other components with no effects on the robustness of the system and where security specifications are tackled without the flexibility losses. In this way, the use of the supervisory control theory (SCT) is considered. Also, a methodology that makes it easier to implement these functionalities at a PLC-based system is presented. A real application of the developed framework is presented, and the implementation is done over an industrial-size device, so the technical feasibility of the methodology is proved. As the framework considers the services offered by the device, it can be used at different manufacturing tasks, so the approach can be applied to any kind of industrial process unit.     

An integrated control framework for flexible manufacturing systems

This paper presents the design, development, and implementation of an integrated control framework that provides a real-time supervisory control model with limited look-ahead capability for flexible manufacturing systems. Control goals and policies are modeled and characterized by a fuzzy rule base, which is integrated with the control model. The framework consists of a finite state machine generator and a controller. The generator model is equipped with an output function and output sets. The controller model has a four-stage decision-making structure. The controller monitors performance measures of the manufacturing system and reacts according to the changes in the system states in order to keep the performance measures at desired levels. The integrated framework has been implemented on a software platform in order to validate its effectiveness. The performance of the framework has been tested on a hypothetical flexible manufacturing system using a simulation .     

柔性制造系统一种次优化的死锁控制设计

为解决柔性制造系统中的死锁问题,以受控系统的许可行为作为指标,根据Petri网基本信标理论,提出了一种次优化的活性控制器设计方法.根据基本信标和从属信标的可控性关系,通过调整控制库所的初始标志,获得了具有较多许可行为的活性Petri网控制器.与文献中其他方法相比,所提的控制策略具有更好的许可性.     

Dynamic control of flexible manufacturing systems

Flexible manufacturing systems (FMSs) are a relatively new technological and organisational approach to helping companies respond to real-time marketing conditions for their production. Under a proposal of the National Bureau of Standards the FMSs are subdivided into virtual manufacturing cells in a dynamic manner, on the basis of group technology.A method of dynamic optimisation for the design of manufacturing processes, capacity balancing and checking, and also production scheduling or rescheduling in virtual manufacturing cells is described. It can be used during real-time production control in FMSs.     

基于多Agent的敏捷制造单元控制系统

针对敏捷制造的需求,本文提出了一种基于多Agent制造单元控制系统的总体结构,并对各Agent的功能与单元控制系统的实现过程进行了详细描述,简单介绍了Agent之间的通信机制.     

基于成本模型的制造单元成组方案优选方法

考虑了设备投资成本、准备成本、物料传输成本等方面,提出了一个简单易用的成本模型,定量地计算制造单元建设和运行的成本,为可重构制造单元配置提供优选方案评估依据。算例说明了该成本模型的有效性。     

Specification methods for material-handling control algorithms in flexible manufacturing systems

Good methods are needed to specify, test, and debug material-handling control logic. This article surveys a number of representative methods for defining and describing control algorithms for programmable material-handling equipment used in flexible manufacturing systems. The methods are evaluated with regard to their suitability for communication between people and as bases for interfaces to automatic program generators. It is concluded that no single method is entirely satisfactory. Three methods (position diagrams, function block diagrams, and operation networks) have potential to be combined into an effective hybrid approach that minimizes the need for the user to switch between various conceptual models.     

基于MES的生产车间管理信息系统

针对制造企业在实施生产管理信息化过程中存在的问题,提出以制造执行系统(MES)为核心的三层结构———企业资源计划(ERP) /制造执行系统(MES) /过程控制系统(PCS)的生产管理信息化的实施方案,用于解决生产与计划相互脱节的难题,实现了车间的现场调度、生产过程控制、在线质量控制,以及对生产过程中“非常规信息”的控制与管理,加强了制造计划的可执行性。     

基于现场总线的柔性制造系统信息实时控制

为实现对STAR-FMS柔性制造系统现场设备的实时控制,设计了基于PROFIBUS-DP的控制系统,解决了控制中心与现场设备的通信问题。阐述了系统构成、PROFIBUS-DP总线的控制方案、通信原理以及信息的实时控制。系统采用S7-300和WINCC作为主站,S7-200、ET200和变频器作为从站。以PROFIBUS-DP总线作为通信基础,既实现了对整个系统的集中控制,又能够分散控制各底层设备,同时使监控画面根据现场实际情况动态显示。应用结果表明,该控制系统设计可行,整个系统运行稳定、可靠,能够实现多级实时控制。     

Job shop scheduling techniques in semiconductor manufacturing

This paper presents a brief review on job shop scheduling techniques in semiconductor manufacturing. The manufacturing environment in a semiconductor industry is considered a highly complex job shop, involving multiple types of work centers, large and changing varieties of products, sequence-dependent setup times, reentrant process flow, etc., in a dynamic scheduling environment. Due to the stubborn nature of the deterministic job shop scheduling problem itself, many of the solutions proposed are of hybrid construction cutting across the traditional disciplines. The problem has been investigated from a variety of perspectives resulting in several analytical techniques combining generic as well as problem-specific strategies. In this paper, we seek to provide a brief overview of the problem, the techniques used and the researchers involved in solving this problem.