Research On Modeling And Design Of Mechanical Product Based On Knowledge Fusion In The Virtual Environment

Virtual Reality (VR) and information technology bring about great innovation in studying and developing method of mechanical product design and manufacturing in the early 21st century. Modeling, designing and simulating have become important parts for studying and developing new products. Therefore the main research content of the thesis is the method of product modeling and designing based on Knowledge Fusion (KF) in the Virtual Environment (VE).Product modeling is studied from two aspects in the paper. To obtain product knowledge information models from reality, and from 3D models of the product. It probes succeessfully how to obtain product information models from the reality and to build knowledge base. The relevant knowledge is reflected to the datebase so that the management method of datebase can be used in the management of knowledge lib. It expounds the 3D modeling method of the visual entity, and puts forward light model method and the theory of 2D/3D model obtaining retrieval, and transformation that the mathematic model can be established based on polygon grid.In the process of design, the method and mechanism of knowledge fusion are studied. The KF is devided into two kinds. The first kind of fusion for reusing knowledge is in the step of product design, which is realized by knowledge reusing and embedding. That is to say the product design can be devided into reuse design and non-reuse design, and the reuse design is devided into absolute reuse and relative reuse, the concept of which are discussed. These factors are analyzed such as similarity property, complicacy that it causes with variability in modeling and expectation degree of designer and so on. It realized decision and design of reuse with the mathematical model. The 8 steps of reuse design are also presented and the model of knowledge reuse and embedding is built up with the similitude property of product function and structure. The second kind is uncertain KF during product design and simulating. The concept of fusion error is proposed firstly. Aimed to the shortage of Dempster-Shafer (D-S) rules under the condition of conflicting evidences, the new extend combination rules are presented for improving the D-S combination rules and the reliability of KF and information fusion. The fusion error of conflict...