【作者】 甘爱军；

【导师】 杨鑫华； 李伟含；

【作者基本信息】 大连交通大学 ， 材料工程， 2008， 硕士

【摘要】 冲模设计的发展是一个不断摆脱经验依赖、提高设计效率,向快速化智能化方向发展的过程。如何提高冲模设计的效率、智能化程度一直是冲模CAD领域的研究重点。本文将基于粗糙集理论的冲模实例推理技术应用到冲模CAD领域,以期充分利用已有设计方案,实现冲模设计的智能推理,提高设计质量和效率,缩短开发周期,降低冲模生产成本。本文首先对基于实例推理技术和粗糙集理论进行了详尽的理论阐述。对当前应用于实例检索的主要方法进行了讨论,总结了它们的适用领域和优缺点。然后在基于实例推理的冲模设计方法基础上,给出了基于粗糙集的冲模设计实例知识表达系统,然后提出了基于粗糙集的冲模实例特征属性约简和权值确定方法,即首先利用粗糙集理论判断实例特征属性的重要度,并将其进行规范化处理,得到各特征属性的权值,该方法可有效地克服传统权值确定方法中对主观经验的过分依赖。最后在分析冲模的实际设计过程和智能CAD系统基础上,建立了基于IDEF0的冲模CAD系统功能模型;提出并建立基于粗糙集的冲模实例推理CAD原型系统的体系结构,建立了基于C/S模式冲模标准件关系数据库子系统体系结构。更多还原

【Abstract】 Being free from great dependence on designer’s experience and being more rapid and intelligent is always the improvement trend of the die-design. How to improve the intelligent level and shorten the design period attract almost all the attentions of the researchers in the CAD (Computer Aided Die Design) area. This paper will apply CBR (Case-based Reasoning) technique based on Rough Sets Theory (RST) in the field of the Die design, so it can implement intelligentized reasoning of Die design using existed project. It should improve the design quality and efficiency, shorten the period of development and reduce the cost of die.Firstly, this paper expatiate CBR technique and RST in details. Then it discusses the mainly technique of case retrieval in current, and summarizes their advantages and disadvantages in applied areas. Secondly, on the basis of introduction of the basic principle of cased-based design methods of stamping die, the knowledge representation of case system is presented in this paper. And then an approach of reducing the feature attributes and calculating the feature attributes weighting is proposed based on rough set theory. i.e., the importance of the feature attributes are calculated first, and then the importance are normalized to weighting coefficients. This method can overcome the shortcoming in traditional methods which depend on subjective experience excessively. Thirdly, in the foundation of the analysis to the practical die design processing and the intelligent CAD system, it builds a functional model based on IDEF0’s Die CAD system. Therefore, this paper brings forward and builds a Die CAD system framework based on CBR-RST. The same time, the related-database system of die criterion cases based on C/S pattern is realized.更多还原