CONCURRENT PRODUCT PORTFOLIO PLANNING AND MIXED PRODUCT ASSEMBLY LINE BALANCING

Reconfigurable products and manufacturing systems have enabled manufacturers to provide "cost effective" variety to the market. In spite of these new technologies, the expense of manufacturing makes it infeasible to supply all the possible variants to the market for some industries. Therefore, the determination of the right number of product variants to offer in the product portfolios becomes an important consideration. The product portfolio planning problem had been independently well studied from marketing and engineering perspectives. However, advantages can be gained from using a concurrent marketing and engineering approach. Concurrent product development strategies specifically for reconfigurable products and manufacturing systems can allow manufacturers to select best product portfolios from marketing, product design and manufacturing perspectives. A methodology for the concurrent design of a product portfolio and assembly system is presented. The objective of the concurrent product portfolio planning and assembly system design problem is to obtain the product variants that will make up the product portfolio such that oversupply of optional modules is minimized and the assembly line efficiency is maximized. Explicit design of the assembly system is obtained during the solution of the problem. It is assumed that the demand for optional modules and the assembly times for these modules are known a priori. A genetic algorithm is used in the solution of the problem. The basic premise of this methodology is that the selected product portfolio has a significant impact on the solution of the assembly line balancing problem. An example is used to validate this hypothesis. The example is then further developed to demonstrate how the methodology can be used to obtain the optimal product portfolio. This approach is intended for use by manufacturers during the early design stages of product family design.     

面向ASP与DFA集成系统的装配模型技术

针对并行工程中的产品装配设计与优化分析 ,提出了一种装配顺序规划与为装配而设计相集成的产品装配分析系统。重点分析研究了集成系统中的产品装配建模方法。首先对现有的各种典型的装配模型技术进行分析比较 ;其次 ,根据 ASP与DFA集成系统的需求 ,设计出了一种包含装配草图、装配关联图信息、装配结构树图、零件设计参数和连接参数等信息的装配模型结构。并结合实例分析了该装配模型的计算机实现方法     

Integrated intelligent design and assembly planning: A survey

This paper reviews the relevant literature of the development of methodologies and systems for integrated intelligent design of assembled products and processes. Based on a combination of the concurrent engineering approach and artificial intelligence techniques, an assembly oriented intelligent scheme for the integration of design and planning is proposed, in which the following components or activities are considered and carried out concurrently and intelligently: assembly modelling and design (conceptual design; preliminary design; detailed design), assembly process planning, assembly system layout and design, assembly simulation, econo-technical (e.g. assembl-ability, assembly time and cost) and ergonomic analysis and evaluation. The literature is reviewed and discussed in relation to the methodologies and systems of implementing the above components or activities and an integrated environment to support them. In addition, some research of our group on this topic is introduced.     

面向并行设计的模具装配模型描述

通过对传统模具ＣＡＤ系统的分析及目前并行工程等先进制造理论对新型模具ＣＡＤ系统的要求,基于一般模具设计过程及ＥＸＰＲＥＳＳ－Ｇ的研究,提出了面向并行设计的模具装配描述模型,同时讨论了已有装配模型的不足。基于此模具装配模型,解释了实现并行设计的方法与过程     

An automated assembly environment in feature-based design

In the integration of design and manufacturing, one of the primary techniques is to evaluate the parts in the assembly so that the labour cost can be reduced. In this paper, the mechanical parts within the design and assembly are examined, and an integrated architecture of an assembly model is proposed which includes a proper assembly environment, the interface between the assembly model and feature-based design, and a knowledge-based expert system for assembly analysis. In order to determine satisfactory plans for assembly and to achieve the required functions in the product model, explicit relational information between the major components is implemented. The evaluation of interference checking of the parts and the geometric tolerances (such as perpendicularity, parallelism, and angularity) of the parts in the assembly model are also studied.     

基于语义关联与驱动的产品概念装配模型研究

面向概念设计的装配模型表示是机械产品装配建模技术研究的一个重要问题,现有的基于几何约束关系的CAD系统不能很好地解决这一问题。基于装配语义“三位一体”性给出了面向概念设计的产品装配模型表示方法,提出采用装配语义关联图表达零件之间的装配语义关系,通过装配语义关联图建立起支持概念装配模型的多层次语义关联和基于语义的装配驱动,从而实现机械产品从概念设计出发的自顶向下和从详细设计出发的自底向上的双向设计。     

产品装配特征的分类与表达技术的研究

将产品的装配特征表达为零件级特征、关联功能级特征和工艺级特征的集合 ,详细描述了各个特征的表达方式。介绍了产品装配分析系统的结构框架 ,它可对产品装配各环节进行分析并为后续生产活动提供信息 ,为并行环境下的信息集成奠定基础。     

基于CATIA中DELMIA的虚拟装配技术的应用

以某产品的模具为例,对虚拟装配技术在模具产品上的运用进行了初步的探讨,从虚拟装配的实现流程、产品的层次结构划分、装配顺序规划及路径规划进行了分析,并基于CATIA实现了该产品组件的装配过程仿真,确定了合理的装配顺序和路径,为虚拟装配技术在产品上的深入应用提供了有益的探索。结合装配工艺的特点和要求,提出了基于虚拟装配技术进行装配工艺设计的流程;最后针对装配工艺设计的实现方法和软件系统做了概述。     

Concurrent and collaborative process planning for automotive general assembly

To ensure competitiveness in today’s automotive market, process planning should be performed concurrently with other engineering activities during new car development. In this paper, new business workflows and the support system for process planning of an automotive general assembly are proposed and presented. Since process planning for a whole general assembly shop is a huge and complex job, several process planners should execute planning together. Therefore, planners should consult with one another regarding his/her results through continuous online communication and cooperation. Process planning based on computers, database and Internet is inevitable for reducing manufacturing preparation time and costs through concurrent and collaborative engineering. In this research, the Web-based process planning system for general assembly shops using the bound operation method is implemented and proven. By using this system, savings in time and cost of assembly process planning are possible, and the reliability of the planning results is greatly improved.     

虚拟装配支持系统中面向多方案工艺规划的研究

主要介绍了我们正在进行的“虚拟装配支持系统”(Virtual Assem bly Support System,VASS)开发计划中面向多方案工艺规划部分的最新进展。这一计划的目的在于开发出一套能够直接或间接地支持产品装配设计、装配工艺规划等工作的软件系统。本文主要论述了这一工作的理论基础。首先 ,对于目前在装配建模方面的研究做了简介 ;然后 ,着力阐述了应用于 VASS系统中面向多方案工艺规划部分的装配信息建模方法与基于规则的推理方法 ;最后 ,对 VASS系统中面向多方案工艺规划部分的体系结构进行了介绍     

Representation of similarity and dependency for assembly modularity

Researchers have expanded the definition of product modularity from function-based modularity to life-cycle process-based modularity, and developed a measure of product modularity and validated a corresponding modular product design method. However, a correct modularity measure and modular design method are not enough to realize modular product design. How the measure and design method are used, especially the role of product representation, is an important aspect of modular design and imperative for realizing the promised cost savings of modularity. In this paper, we develop a representation that includes similarity and dependency for assembly modularity. The similarity representation is based on assembly cost factors including tool changes and fixture changes. The process-based design dependency representation is based on design features that impact the assembly process (faces, fasteners, assembly interference, etc.). This representation captures the cost benefits of modularity and can be extended to other life-cycle processes. A set of products is used to show the application of this representation in association with a modularity measure and modular design method.     

INTEGRATED APPROACH TO ASSEMBLY SEQUENCE PLANNING OF C0MPLEX PRODUCTS

Assembly sequence planning will be more difficult due to the increasing complexity ofproducts. An integrated approach to assembly sequence planning of complex products applying de-composition-planning-combination strategy is presented. First, an assembly is decomposed into a hier-archical structure using an assembly structure representation based on connectors. Then, an assemblyplanning system is used to generate the sequences that are locally optimal for each leaf partition in thestructure hierarchy. By combining the local sequences systematically in a bottom-up manner andchoosing suitable ones from the merged sequences, the assembly sequence of each parent structureincluding the whole assembly is generated. An integrated system has been completed. A complexproduct is given to illustrate the feasibility and the practicality of the approach.     

基于智能 CAD 系统的产品建模方法

研究了基于智能ＣＡＤ系统自顶向下的产品建模方法,以胶印机凸轮连杆机构为例,以变量设计技术为基础,建立了该机构的概念模型、装配模型和零件模型。不仅实现了运动仿真、结构仿真和工作点运动规律的输出,而且,通过模型与变量、变量与变量之间的关联,建立了它们之间的设计参数双向传递机制,实现了三种模型的联动设计,为并行设计创造了条件。     

面向整体设计的客车件冲模CAD系统的实现

基于现代设计方法和计算机信息技术 ,开发了基于功能 -结构映射、支持自上而下整体设计的客车件冲裁模CAD系统。介绍了系统的总体结构、模具设计功能树的建立思想和层次化部件装配模型的特点 ,阐述了模具结构设计过程中不同层次上设计信息的处理方法 ,并通过一功能元件的设计实例说明了基于该系统的冲模设计过程。     

面向自顶向下设计的装配模型研究

装配模型是支持数字化产品设计和制造的重要基础。设计人员通过装配建模表达产品的功能形状和设计师的设计意图。本文针对自顶向下设计模式对装配模型的特殊要求 ,提出一种面向自顶向下设计的装配模型 ,支持产品设计过程中的多种设计活动。给出了模型的维护方法 ,为自顶向下的装配设计提供了安全的数据支持。该模型为产品装配的自顶向下设计提供了良好的模型基础。     

产品装配序列生成、DFA分析和装配仿真集成系统研究

提出了层次等级关联关系产品装配模型和新的DFA分析方法,它通过计算装配效率和零件功能难度比来评价产品装配性能,从产品并行设计要求,产品装配序列生成、DFA分析和装配仿真集成是开发先进的计算机辅助装配工艺系统（CAAPP）的关键。这里叙述了集成系统设计方法及已研制的适合减速器产品的系统功能、工作过程和示例。     

面向大型产品装配序列规划的分类方法研究

讨论了在对大型产品进行装配序列规划时 ,为了简化装配序列产生过程 ,需要对待装配大型产品按操作复杂度分成两类 ,即复杂装配部分和简单装配部分 ,复杂部分进行虚拟装配规划 ,简单部分进行自动装配规划。分类时 ,首先对装配产品进行子装配体识别以得到组件 ,然后利用分类算法将组件分为两类。     

面向装配的设计型专家系统的研究与开发

叙述了用于评估零件装配困难度并为设计者提供产品再设计参考意见的专家系统的开发情况。所开发的辅助产品 Ｄ Ｆ Ａ 分析的专家系统经过测试是有效的。这种基于计算机的方法使产品的 Ｄ Ｆ Ａ 分析更快、更容易,即在一礼品盒机器人化柔性自动装配线的研究中利用该系统对礼品盒进行了易于装配的再设计,结果改善了这种产品的装配友好性,其装配成本也明显降低。     

基于I-DEAS平台的产品装配仿真系统的开发

对于尚处在设计阶段的产品来说,可装配性好坏最直观的效果是在计算机上仿真产品的实际装配过程。为此提出并实现了一种基于I-DEAS平台的装配仿真系统,该系统可有效地对产品的可装配性进行评价,并验证装配工艺规划结果,并在此基础上生动直观地进行产品的预装配,以检测与装配有关的问题而无需实物模型。     

面向过程的虚拟环境中产品装配建模研究

提出了面向过程的虚拟装配建模方法,在虚拟环境中将装配建模与装配仿真相结合,建立装配关系模型的同时,实现了对装配过程的创建与仿真,从而,在虚拟环境中将面向结果的装配建模发展为面向过程的装配建模.设计者采用直接三维交互进行装配建模操作的同时,系统通过装配关系识别自动捕捉设计者的装配设计意图,通过装配约束运动确定零件的装配路径,通过虚拟装配建模过程信息重用为装配规划提供有效的支持.开发了面向过程的虚拟装配建模原型系统.实践表明,面向过程的虚拟环境中产品装配建模方法有效地提高了产品装配设计的质量与效率.