Rule-based production planning in flexible manufacturing systems

Production planning in flexible manufacturing may require the solution of a large-scale discrete-event dynamic stochastic optimization problem, due to the complexity of the system to be optimized, and to the occurrence of discrete events (new orders and hard failures). The production planning problem is here approached for a multistage multipart-type manufacturing shop, where each work cell can share its processing time among the different types of parts. The solution of this problem is obtained by an open-loop-feedback control strategy, updated each time a new event occurs. At each event time, two coupled problems are solved: 1) a product-order scheduling problem, conditioned on estimated values of the production capacities of all component work cells; and 2) a production-capacity planning problem, conditioned on predefined sequences of the product orders to be processed. In particular, the article aims at defining a production planning procedure that integrates both analytical tools, derived from mathematical programming, and knowledge-based rules, coming from experience. The objective is to formulate a hybrid (knowledge-based/analytical) planning architecture, and to analyze its use for multicell multipart-type manufacturing systems.     

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。     

Enhancing moulds manufacturing by means of reverse engineering

Modern CAD/CAM techniques together with five-axis high-speed milling allow to reduce moulds manufacturing time and costs. Nevertheless, in order to put a mould into use, operations of manual finishing and fitting are still always required. Such operations, performed manually by mould makers, modify the milled surfaces of moulds. Reverse engineering techniques can be employed in quality control to evaluate dimensions and geometrical tolerances on moulds after machining and fitting. Changes in the product’s shape are sometimes decided after a mould has already been machined. In such cases, if possible, the mould maker directly modifies the mould. Thus the final real geometry of the mould does not reflect the one of the original CAD model. The aim of this paper is to point out the benefits of non-contact quality control and to illustrate a procedure, based on reverse engineering techniques, to reconstruct and update the mathematical model of the mould after it has been polished and fit. The procedure was tested on a mould for the production of a plastic camera body that was previously inspected by means of a structured light scanner.     

AGV schedule integrated with production in flexible manufacturing systems

Flexible manufacturing systems (FMS) comprise, automated machine tools, automated material handling, and automated storage and automated retrieval systems (AS/RS) as essential components. Effective sequencing and scheduling of the material handling systems (MHS) can have a major impact on the productivity of the manufacturing system. The material handling cannot be neglected while scheduling the production tasks. It is necessary to take into account the interaction between machines, material handling systems and computer. In this context, this paper attempts to link the operation of automated guided vehicles (AGV) with the production schedule and suggests a heuristic algorithm that employs vehicle dispatching rules (vdr) for conflict resolution. The vdrs considered in this paper are: shortest operation time (SPT), longest operation time (LPT), longest travel time (LTT) and shortest travel time (STT). The performance of the vdrs in the proposed heuristic is compared with makespan criteria. The results show that the STT provides the best solutions compared to other vdrs.     

Control and process-based optimisation of spot-welding in manufacturing systems

This paper documents a research program undertaken by the CIM Centre at the Industrial Research Institute Swinburne (IRIS) in collaboration with a major automotive manufacturer. The objective of the research was to examine potential mechanisms for improvement of the spot-welding process, which is a major component of automotive assembly. In particular, both traditional techniques for improving suboptimal parameters in the process and advanced techniques, based upon digital signal processor (DSP) control of the process (using acoustic-emission feedback), were applied to an industrial spot-welding test-case. This paper documents the outcomes of the two techniques and we demonstrate how significant improvements can be made to the overall spot-welding process through the adaptation of such technologies.     

基于MES系统的智能制造切削加工系统架构设计

随着信息技术和新的制造工艺的发展,智能制造技术成为传统制造企业产业升级的关键技术。MES系统在智能制造系统中的作用是贯穿始终的,且与PLC通信采取应答机制。该文设计了智能制造切削加工系统的总体架构,并结合MES软件将数控车床、加工中心、PLC、机器人、RFID及立体仓库等信息系统进行有效结合,完成了生产过程的智能化管理,对同类企业进行智能制造技术的应用提供了可借鉴的经验。该系统可降低没有附加价值的活动对工厂营运的影响,进而改善企业制程,提高生产效益。     

离散制造企业MES中的生产数据采集实践

根据在离散制造企业对MES中生产数据采集的实践,总结了离散制造企业生产数据采集的特点.将其生产数据进行分类归纳,分为带有时标的生产过程数据、带有时标的生产事件信息、计量数据以及物料批次信息.提出了基于完整性与实时性原则、多种采集技术综合应用与人机结合原则、易于集成应用原则建立的数据采集方案.归纳了针对不同类型生产数据,DNC网卡采集方式、宏指令采集方式、PLC采集方式以及RIFD采集方式利弊.采用航天企业的实际案例说明了研究内容.     

考虑生产能力约束的制造系统双重资源近似优化配置

针对操作工与设备相互间存在复杂的约束关联等问题,基于模具企业典型的模具加工工艺过程,综合考虑人与设备,建立了一种易于求解的线性整数规划数学模型,并运用Lingo得到该模型的最优解.为了验证数学模型的求解结果,根据该类制造系统典型的运作模式,建立了仿真模型,并进行了仿真实验.实验表明:由于模具的实际生产系统受订单到达时间、调度策略、缓存区大小等限制,虽然实际所需的设备及人员的数量比按照所提出的数学模型得到的新增设备及人员数量略多,但是考虑到求解的便利性,数学模型的近似程度可以接受.     

MES环境下离散型制造企业设备管理系统研究

在分析离散型制造企业设备管理特点的基础上,阐述MES环境下离散型制造企业设备管理系统的内部结构、流程及系统功能模块,并实现了系统的开发.     

WTO条件下我国机械制造业面临的机遇、挑战及对策

阐述我国制造业发展现状,入世给我国制造业带来的机遇与挑战.提出我国制造企业要占领世界市场,必须提高自主开发和技术创新能力,重视先进制造技术的发展,加强政府引导,加强与国际大型企业及国际相关组织的交流合作,强化人才培养机制.     

基于射频识别的离散制造业制造执行系统设计与实现

针对离散制造业企业资源计划的计划层与现场过程控制层间信息和管理的断层而引起的生产管理问题,在制造企业内部引入射频识别电子标签跟踪在制品,同时在部分应用中兼容条码技术.提出了通过工位和车间控制器协调配合完成生产计划的下发和现场生产数据的实时采集,通过系统集成接口实现制造执行系统与企业资源计划系统的数据和业务集成,实现了制造和质量的可视化和数字化管理.详细介绍了具有良好开放性和可扩展性的系统结构和主要功能模块.该系统在汽油机生产线现场应用的结果表明,生产效率和生产质量得到明显改善.     

MES中分布式制造资源竞争仲裁方法及其应用研究

为解决制造执行系统重构难题,指出重构本质是制造资源的选择和优化.分析了MES资源选择与以往提到的在虚拟企业中选择合作企业的不同之处,详细介绍了MES资源选择问题描述,基于层次分析法原理,建立了资源竞仲裁决策方法,最后重点阐述了具体解法和算例,结果验证了方法有效性.     

Optimal production control and marketing plan in two-machine unreliable flexible manufacturing systems

In this paper, we have developed a production planning and marketing model in unreliable flexible manufacturing systems with inconstant demand rate that its rate depends on the level of advertisement on that product. The proposed model is more realistic and useful from a practical point of view. The flexible manufacturing system is composed of two machines that produce a single product. Markovian models frequently have been used in modeling a wide variety of real-world systems under uncertainties. Therefore, in this paper, the inventory balance equation is represented by a continuous-time model with Markov jump process to take into account machines breakdown. The objective is to minimize the expected total cost of the firm over an infinite time horizon. While the total cost consists of the cost of the product surplus, the cost of the production, and the cost of the advertisement. In the process of finding a solution to the problem, we first characterize an optimal control by a class of linear stochastic system where some parameter values are subject to random jump. By defining quadratic cost functions and characterizing the associated limiting optimal control problem, a discrete-time approximation model and an asymptotic optimal control model are developed. It is clear that such a solution exists and can be obtained as a limit of a monotonic sequence with solving the steady-state Riccati equation.     

基于MES的车间制造过程动态质量管理系统研究

针对车间制造工程质量管理的现状和不足,在研究制造执行系统(Manufacturing Execution System,MES)应用现状的基础上,提出和研究一种基于MES的车间制造过程动态质量管理系统,实现质量计划、质量实施、质量检查和质量处理四个阶段动态循环地执行.给出系统的体系结构,并对系统实现的部分关键技术进行研究.最后将该系统在一家企业进行了应用实践,取得了良好的应用效果.     

Design and manufacturing of ear prosthesis by means of rapid prototyping technology

In this paper, the complete procedure to design and construct reusable moulds for implant-based ear prosthesis and manufacture substructures by means of a computer aided design-computer aided manufacturing (CAD-CAM) procedure and rapid prototyping (RP) technology is presented. The scan of the healthy ear, the virtual superimposition of its mirrored image on to the defective side, and the rapid manufacturing of the substructure and of the mould eliminate several steps of traditional procedures (wax, stone, try-in). Moreover, the precise design and customization of the substructure is presented, with the original and engineered shape for the retention of the silicone. The time and cost saving results of this protocol are presented together with a discussion of the main design features that make the prosthesis a stable and reproducible system to improve rehabilitation of patients with auricular defects or absence.     

生产系统的新发展--可重构的生产系统

随着经济的全球化，企业面临的市场竞争空前激烈。企业为求得生存和发展，不仅要关注产品的创新外发，还必须进行产品生产方式的变革。努力应用新技术、新工艺，推动生产系统不断地发展变化。可重构的生产系统就是美国学者十多年前提出的一种生产系统发展的新模式，并在美国密歇根大学工程学院的工程研究中心进行了比较系统的研究。变革生产系统的目的是提高生产牢，归根到底就是要提高企业的效益和竞争力。这项课题一经提出，立即引起各国制造业界的高度关注。     

面向服务的制造系统中制造服务供需匹配研究综述与展望

鉴于现有的制造服务供需匹配的相关研究尚缺乏统一的概念与研究体系,为促进面向服务的制造系统的发展与应用,对面向服务的制造系统中制造服务的供应与需求、制造服务供需匹配的概念进行了总结;从不同角度将该供需匹配问题分为供需对象匹配、供需数量匹配、单一产品/服务供需匹配、多产品/服务供需匹配、企业供需匹配和系统供需匹配六类;针对供需静态、需求动态、供应动态、供需动态和过程动态五种情况,分别从不同的研究模型和实现方法两方面描述了制造服务供需匹配的相关研究现状,并探讨了未来面向动态环境的社会化制造服务供需匹配的研究趋势。     

Development of integrated manufacturing systems

The productive operation of a new manufacturing system must first of all be preceded by its efficient design and integration. The design of new manufacturing systems requires an in depth knowledge of current operational paradigms and their application to manufacturing. The integration of new manufacturing systems requires tools and techniques which take cognisance of the social as well as technical environment. This paper looks at an approach to the integration of advanced manufacturing systems, which utilizes the latest developments in social and technical design methods, and in particular the application of structured methodologies and sociotechnical design techniques to the development of next generation manufacturing processes.     

基于MES的智能生产调度系统研究与实现

根据现代制造企业生产调度的要求,采用基于启发式算法和遗传算法相结合的智能生产调度算法,建立了基于MES的智能生产调度系统。详细提出了该系统的总体结构及其实现流程;介绍了基础数据库、作业调度、结果输出以及系统维护四大功能模块的具体内容;实现该系统的关键技术,其中包括该混合算法的具体实现过程、标准工时数据库的建立硝及系统实现的技术支持。该系统弥补了单一算法的不足,能够取得良好的调度效果,从而提高企业的生产效益。