设计型专家系统工具的研究与设计

Research and Development of a Development Tool for Designing Expert Systems

本文针对工程设计的特点,提出了一个通用的设计型专家系统工具的系统结构,论述了该工具系统的设计与实现方法。利用该工具初步构造了一个压延零件成形方案的确定及其模具设计专家系统,实践表明该工具系统具有良好的性能。

Considering the characteristics of engineerign design, we have established a universal development tool for designing expert systems. Engineering design requires a lot of special knowledge and skill. The research on designing expert systems began only about ten years ago, and their development was slow because of the complexity of engineering design[2]. To date most designing expert systems are rule-based ones [1-3]. Rule-based expert systems are effective for dealing with some medical and geological problems[8], but they can solve only simple and small scale design problems, which are basically the design problems of the parts of products [1,2]. Thus it is necessary to search for designing expert systems that are effective for complex design problems and to search for their development tools. The tool introduced in this paper possesses two new features: (1) The designing expert systems developed by the tool are able to deal successfully with complex and large scale design problems, such as the design of complete products. (2) In the tool introduced in this paper, the design tasks are represented by task-class knowledge sources, the handlers of tasks are islands and the control of the tool is realized through blackboard. The authors consider it worthwhile technically to discuss the two new features in some detail. The tool provides lots of knowledge representation modes. These modes include framework, list, rule, and task-class knowledge source, and include island and control knowledge source. Thus design knowledge can be expressed effectively. It makes design knowledge representation in better comformation with norm, since the expression of tasks is separated from that of task handlers. The systems so developed are able to simulate successfully the design modes of experts since task-class knowledge sources are managed by islands. And they can solve complex design problems since the control of the systems is realized through blackboard. With the tool presented in this paper, we have constructed a designing expert. system for the design of deep-drawing dies. The performance of the dies proves that our tool is sat- isfactory.