【作者】 王珂；

【导师】 廖文和；

【作者基本信息】 南京航空航天大学 ， 航空宇航制造工程， 2007， 博士

【摘要】 当前制造业全球化的发展趋势和日益加快的产品更新速度迫使机械制造行业的竞争焦点转向对市场的快速响应和产品创新。支持快速设计的CAD系统开发和应用是提高企业快速响应和创新能力的关键环节之一。本文以国家863重大专项、省高技术研究项目为依托,着重研究了应用CBR技术实现以机械产品快速设计为目标的快速设计系统的构建方法及关键技术,开发了支持工程机械产品开发的快速设计系统。论文的主要研究成果及创新点如下:1)提出了基于XML的复杂实例表示模型和基于树结构的实例库组织关系模型。利用对象模型、基础类定义、XML模式与多目标链接技术实现以树形结构为主、具有动态特性的复杂实例表示,并提出和构建了支持实例动态化存储与管理的多层次动态实例库,运用原生XML数据库与关系数据库两种方式实现了设计实例与关系模型的合理组织,为基于ASP的网上实例库与协同设计的实现奠定了基础。2)从提高系统求解性能和运行效率的角度出发,提出了基于模糊粗糙集的实例库维护策略。通过模糊差异向量提取和约简模糊修正规则,选择代表性实例更新实例库,从而达到维护和精简实例库的目的,克服了基于粗糙集理论的传统实例库维护策略在处理不确定问题与对象分类等方面存在的不足,降低了实例库维护工作的复杂性,并在实际应用中检验了新策略的性能与优点;3)提出一种复合型相似性度量方法,从语义和结构两方面描述实例间的匹配程度,所提出的多层次实例检索模型能够通过对特征属性分类提高属性间的区分度,同时提出了基于位索引(Bitwise Indexing)和相似度映射表(Similarity Mapping List)的检索算法,采用位运算和复用相似度计算结果的策略来提高检索速度,并结合实验证明了该算法的简洁性与高效性;4)在分析机械产品设计特征的基础上,以CommonKADS建模方法为指导,给出了基于PCM方法的任务结构模型和实现设计知识的规范表示与获取的知识获取工作表,并以此为基础,提出了四层结构的产品设计知识模型,分析了支持产品设计知识组织表示的产品设计任务分解结构及其表示方法,为复杂机械产品设计知识的分层、分类表示与有效获取提供了可靠的方法。5)针对系统体系结构框架和开发过程中的关键问题,对系统的开发体系结构、数据模型设计和系统总体结构框架进行了分析,介绍了系统设计流程导航、产品设计向导等关键功能的实现,并将研究成果——工程机械快速设计系统在镇江华晨华通路面机械有限公司等企业中进行了应用验证,取得了令人满意的效果。更多还原

【Abstract】 Nowadays, the trend of manufacturing sector globalization and the accelerating pace of product refresh rate shifts the focus of manufacturing industry competition in the market’s rapid response and product innovation. The development and application of CAD system for rapid design is one of the key links to improve enterprises’rapid response and innovation capability. Supported by National 863 Projects and provincial High Tech Research Projects, intelligent design system’s building approach and key technologies to achieve rapid design of mechanical products by CBR technology are emphatically studied, a system supporting the construction machinery product rapid design is developed. Main study results and innovations are as follow.1) A XML-based complex case expression model and case base organizational model based on tree structure are proposed. Using the object model, foundation class definition, xml schema and links technology to express the tree-structure-like complex case with dynamic characteristics, multi-level dynamic case base for dynamic case storage and management is proposed and built, Native XML database and relational database are utilized to organize the case and relational model properly, which laid the foundation for the building of on-line resource library and implementation of collaborative design;2) In order to enhance the system performance and operating efficiency, a case base maintenance policy based on fuzzy rough sets theory is put forward. Mining and reduction fuzzy adaptation rules by fuzzy discrepancy vector, updating case base by representative cases so as to maintain and simplify the case base, which reduces the complexity of maintenance work and the performance and advantages of this new strategy is tested in practical application.3) A composite similarity measurement is introduced to describe the matching extent of cases from the semantic and structural aspects, A multi-level retrieval model, which can enlarge the distinction between feature attributes by classifying them, meanwhile, a new retrieval algorithm based on bitwise indexing and similarity mapping list is presented, which raises the retrieval speed by bitwise operation and reusing similarity calculation results. Finally, the conciseness and efficiency of this algorithm is proved by example;4) On the basis of analyzing the mechanical product design features, take the CommonKADS modeling method as instruction, PCM methodology-based task-structure model and working-sheet for expressing and acquiring design knowledge are presented, and on this basis, a knowledge modeling of four-layer structure is proposed, product design task decomposing structure and expression method supporting product design knowledge organization and expression is analyzed, which provide a reliable method for acquisition and expression of product design knowledge in lamination and classification.5) Referring to the key issues of system framework and development process, the development architecture, data model design and system framework are analyzed, key functions are introduced, such as design process navigation, product design guide, etc. Finally, the research findings-construction machinery rapid design system is applied in several domestic machinery manufacturing enterprises and achieves satisfactory results.更多还原