【作者】 叶晓峰；

【导师】 李建军； 王义林；

【作者基本信息】 华中科技大学 ， 材料加工工程， 2010， 博士

【摘要】 板金零件被广泛应用于汽车、航空航天、机械、家电等领域,随着制造业的快速发展,它的形状越来越复杂、精度要求越来越高,使得其成形制造的难度也越来越大,也因此对冲压模具的设计和制造提出了更高的要求。由于板料成形过程复杂,需要考虑的因素很多,其设计质量的好坏依赖设计者的经验。因此,采用基于知识工程的理论与方法,结合冲压模具设计知识,研究冲压模具的数字化设计制造技术具有重要意义。本文采用知识工程领域最新的前沿技术——知识重用技术,探讨并解决了冲压模具设计中关键技术问题,研发了基于知识的冲压模具设计系统,为提高冲压模具设计效率与质量提供了有效的技术支撑。在本文中,作者首先研究了知识与数据和信息的区别,以及知识的分类与转化过程。按照冲压模具设计过程,对冲压模具设计中关联的相关知识进行了分析与组合分类,将冲压模具设计中所涉及到的基础知识、标准与规范、典型冲压模具案例以及设计过程知识分为单元知识、模型知识以及实例知识三类,为实现基于知识重用的冲压模具设计奠定了基础。通过对现有知识表达方法及其存在的问题、以及冲压模具智能化设计特点的分析,提出了基于XML (eXtensible Markup Language)语言的知识表达与应用方法。在设计知识重用理论及概念模型的基础上,研究分析了冲压模具设计各个阶段知识重用的方法,建立了设计知识重用的层次与模型,并分析提出了在CAD、KM和CBR技术基础上,如何实现整个设计过程的知识重用的方法。根据上述研究成果,针对冲压模具设计过程中的概念知识、图表知识、公式知识、事实性知识以及规则性知识等单元知识,提出了基于XML的单元知识表达模式和结构。针对冲压模具设计过程中与形状相关的知识处理问题,提出了形状重用模型,用于设计过程中几何形状、特征形状等相关知识的重用。并以标准件重用为对象,采用XML统一地表达标准件设计过程中涉及到的尺寸选用知识和装配应用知识,建立了基于知识重用的标准件库,实现了标准件使用过程的自适应以及标准件的自动开孔功能。由于在模具设计过程中,经常会采用已有的成功设计案例,进行新产品零件设计。为此,研究了基于CBR的冲压模具设计知识重用技术。结合冲压模具设计的特点,将冲压零件工艺特征匹配作为冲压模具设计过程中实例匹配的检索依据,提出了冲压工艺特征的相似性判断方法,并采用XML方法描述了冲压工艺特征及其匹配过程,从而实现了基于实例的冲压模具设计。在上述研究成果技术上,作者在课题组已有研究成果的基础上,在UGNX平台上,开发了统一的冲压模具设计知识重用平台。应用表明,该平台具有较好的实用性,所提出的理论和方法在冲压模具设计过程中,可以有效的解决设计过程中的知识重用问题,提高设计效率和质量,已在代表国际先进水平的UGNX连续模设计系统PDW中获得应用。更多还原

【Abstract】 With the rapid development of manufacturing industry, sheet metal parts with more complex shape and higher manufacturing precision are widely used in automotive, aerospace, machinery, household appliance and other fields. Therefore, higher requirements are put forward for design and manufacturing of stamping die. Complicate factors in design phase is considered due to the complexity of sheet metal forming process, anddesign quality mostly depends on the experience of designer at present. Consequently, theory and methods based on knowledge engineering, combined with stamping die design knowledge, are significant to study digital technology of stamping die design and manufacturing. Key technology on stamping die design is researched in this dissertation. Adopting the latest frontier of knowledge engineering techniques—knowledge reuse, knowledge based stamping die design system is developed. As a result, efficiency and quality are improved during the design process.The difference of data, information and knowledge, knowledge classification and transformation are discussed in this paper. According to the analysis of related knowledge, design knowledge involving basic knowledge, standards, specification, typical case and process knowledge, is divided into element knowledge, model knowledge and case knowledge, so as to provide a basis for knowledge based stamping die design.With the analysis of current knowledge representation method and existing problems, considering the characteristics of intelligent design of stamping die design, a general architecture of knowledge representation and application based on XML (eXtensible Markup Language) is proposed. Key points of knowledge reuse throughout each stage of stamping die design are studied. Hierarchy and model on design knowledge reuse is established on the basis of the knowledge reuse theory and conceptual model. In order to realize the reuse for whole design process, knowledge reuse must be built on the development of CAD (Computer Aided Design), KM (Knowledge Management) and CBR (Case-based Reasoning) technology.Expression pattern and structure of element knowledge based on XML are put forward according to the research results of element knowledge during stamping die design phase, including definition knowledge, chart knowledge, formula knowledge and rule knowledge. Shape reuse model, which can be applied to geometry and feature knowledge reuse, is proposed aiming at shape related knowledge processing during the design phase of stamping die,. For standard parts, size knowledge and assembly knowledge are represented with XML in the design phase, consequently, knowledge based standard parts library is established to realize the self-adaption and pocket for standard parts.During the process of stamping die design, the development of new product is generally referred to successful design case. Consequently, knowledge reuse technology for stamping die design based on CBR is studied. Since process feature matching of stamping parts can be referred for case matching, similarity judgment method for stamping process feature is investigated in consideration of the characteristics of stamping die design. Thus, case based stamping die design is realized.Based on the theory and methods mentioned above, a uniform knowledge reuse module for stamping die design is developed on the platform of UGNX. It is verified by application that problem of knowledge reuse on stamping die design is solved with the theory and methods proposed in this dissertation, the system with high practicality is used in progressive die design module on the platform of UGNX.更多还原