Research On Several Key Technical Problems Of A Concurrent Design System And Its Implementation

In light of deep analysis of the development of current product design, and the latest study proceed of concurrent design theory and methods, combined with requirements of the project "System of Design For Manufacture and Assembly", several key technical problems, including product modeling, feature recognition and model reconstruction, knowledge organization and knowledge representation, reasoning mechanism, and parametric design approach as well are researched. Based on this, the prototype system of integrated concurrent design is completed.First, characteristics of product models in traditional design and concurrent design are compared. Therefore, thoughts of design object and design process working in the double harness are put forward. And, two typical representation methods of product model, and their localization are expatiated. Concept of generalized engineering semantic feature (GESF) is defined. State of product design model is expressed. Then, an integrated representation method of product model is advanced. Based on the Pro/Engineer software platform, product-modeling system for product general information model is set up.Second, relationships between different product models and approach of data exchange are analyzed. Algorithms of automatic feature recognition are elaborated by the instance of rotation feature with complex section. By structure tree of feature in the Pro/E software, three steps strategy of Pro/E-based feature information extraction, and rules of feature information model reconstruction are concisely presented.Third, knowledge composition, classification and characteristics of guideline for product design are studied. Strategy of knowledge organization by sorting code is presented. In the basis of feature expression, common methods of knowledge representation, and requirements of improving the reasoning efficiency as well, an integrated knowledge representation method is brought forward. To the characteristics of knowledge about manufacture resource, object-oriented expression method is used. Methods of knowledge organization and knowledge representation are elaborated in the example of presenting testability knowledge.Fourth, analyzed function and performance request of system reasoning engine, the mixed reasoning mechanism by case-based reasoning (CBR) and rule-based reasoning (RBR) is adopted. Hence an intelligent design-for-X (DFX) reasoning system is built. By the way, reasoning strategy and flow of reasoning complement are described. And, areasonable 3D search model is put forward.Fifth, a novel method based on Pro/E software and can integrate with generalized optimization module smoothly is put forward. Approaches for coordinating relationships between generalized optimization models and parameter models of products, establishing variables mapping, and resolving geometric constraints are elaborated. The algorithm of automatic regenerating geometric models also is proposed. Product parametric automatic regenerating prototype module is established.Finally, the mature PDM technique and main function module of PDM system are introduced. By the means of encapsulation and integration, a concurrent design prototype system is made up of self-made PDM system and applied multi design tools.