【作者】 王明艳；

【导师】 李萍；

【作者基本信息】 合肥工业大学 ， 材料加工工程， 2009， 硕士

【摘要】 冲压件工艺设计是一项复杂的大系统任务,随着国民经济的发展,生产部门对冲压件工艺设计的效率提出了更高的要求。目前,想从根本上提高冲压件工艺设计的自动化程度,提高设计效率和设计质量,人工智能(AI)技术的应用将发挥举足轻重的作用。专家系统(ES)是一个智能计算机程序,它利用知识和经验,通过推理来解决某领域中只有人类专家才能解决的难题。它的研究和应用已经成为全世界人工智能研究的热点和焦点。专家系统运用专家的知识与经验进行推理、判断和决策,是解决冲压工艺设计效率问题的有效方法。推理机是专家系统的思维部件,是专家系统的重要组成部分之一。因此,冲压工艺设计专家系统推理机的研究,对构建冲压工艺设计系统具有十分重要的理论意义和应用价值。冲压工艺设计专家系统利用人工智能技术为冲压专业设计人员提供智能化、建设性的设计帮助。区别于传统的程序,通过模拟专家的思维过程,利用知识来推理出结果,其结构可表达为“专家系统=知识+推理”,知识库是基础,推理机是它的核心。本文着重论述了推理机的设计和实现过程。本文建立了冲压工艺设计专家系统推理机的结构模型;结合有关参数、机理公式等知识特点,基于产生式规则的知识表示形式,给出了匹配度的定义及计算方法,以及基于匹配度的冲突消解策略;利用可信度的概念,采用了用于系统推理的基于可信度的不确定性推理方法;微软.NET平台给专家系统开发提供了一个非常好的基础系统平台,充分利用面向对象技术,设计了正向推理的启发式专家系统的推理机。系统很好地实现了知识处理与用户交互的分离和推理机与知识库的分离。基于匹配度的冲突消解策略,可以很好地解决冲压工艺设计规则的选择问题;基于可信度的不确定性推理方法能够提高推理结论的可信度。在此基础上设计的专家系统推理机能够快速准确地获取较优的推理结果。最后,利用该系统对一个具体零件冲压工艺进行了设计,得出了较为满意的结果。更多还原

【Abstract】 Stamping process design is a complex systematic task. With the development of national economic, the manufacturers bring forward high requirement of the efficiency of stamping process design. Now, the radical improvement of the automation of stamping process design system, and the improvement of the efficiency and quality of the design, will depend much on the application of artificial intelligence(AI) techniques. An expert system(ES) is a computer program that is designed to emulate the logic and reasoning processes that an expert would use to solve a problem in his/her field of expertise, using artificial intelligence technology. The research and application of expert system have become the researching focus of the artificial intelligence of the world. Expert system, which using the experts’knowledge and experience to reason and make decision, is one effective way to solve the efficiency of stamping process planning. Reasoning machine is the thinking part of expert system and it is the one important part of expert system. Therefore, the research of expert system reasoning machine for stamping process planning has important theoretical significance and actual value to building the system for stamping process planning.Expert system for stamping process planning applies artificial intelligence technology to aid professional pressing designers with intelligent and constructive help on the design. Distinct from the traditional process, it has simulated the expert thinking process and used such knowledge to get the results, therefore its structure can be concluded as“expert system = knowledge + consequence”with knowledge database as foundation and consequence machine as its core. This essay focuses on the design and realization of this reasoning machine.In this paper, the structure model of expert system reasoning machine for stamping process planning was built. The definition of matching degree and its calculation was given based on the knowledge representation form of production rule, which combined with the knowledge characteristics, such as the related parameters and mechanism formulas, etc. Then, the conflict reduction strategy based on matching degree was presented. The uncertainty reasoning method based on the believable degree was proposed using the concept of believable degree. Microsoft .NET platform provides a very good basic system platform for expert system development. The direct heuristic reasoning machine of expert system was developed by using the .NET technology.The system can separate business transaction from client interaction and reasoning machine form knowledge base well. The conflict reduction strategy based on matching degree can solve the problem of choosing stamping process planning rules well. The uncertainty reasoning method based on believable degree can improve believable degree of the conclusion. The designed reasoning machine of stamping process planning expert system can obtain better inference results more fast and accurate. At the end of this paper, an example of stamping process design for a material part is demonstrated the reliability and practicability of the methods.更多还原