Research And Application Of 3D CAD Model Retrieval Technology Based On Feature Information

Product design and manufacturing based on 3D CAD model has become the mainstream pattern of China's manufacturing industry,if the design resource of parts library could be reused effectively,which can significantly reduce product development time and cost,meet the needs of model reuses.Meanwhile,3D CAD model retrieval technique can achieve precise,rapid design reuse for product three-dimensional model of resources.In order to efficiently reuse the features and process information of the 3D CAD model products for manufacturing field,by analyzing the features and attribute information of 3D CAD model geometric,this article in-depth study the definition and representation of feature information of 3D models based on MBD and ontology technology.A kind of 3D CAD model researching algorithm based on the product attributes data information and manufacture process information,which implements the 3D CAD model retrieval system for different stages of engineering design.The research content of this paper mainly includes the following aspects:(1)By analyzing the information characteristics of mechanical and electronic products in railway electrification industry,the ontology of parts library's resources was built,and the expression,identification and extraction of the feature information based MBD model were researched,which provided data basis for the following model retrieval method.(2)The semantic similarity calculation method based on ontology structure was studied.By considering the factors such as the semantic distance between the ontology concepts,the weight of the directed edge,semantic coincidence degree and so on,this method categorized the model feature information-attribute data information and analyzed its semantic similarity,meanwhile proposed an extended query program with the combined retrieval conditions based on product category,function,or attributes.Finally,an example of searching a type of contact was presented to illustrate the effectiveness of that program.(3)Three-dimensional CAD model retrieval algorithm merged with process marking information was studied.On the basis of building the feature adjacency graph of a model,this algorithm analyzed the similarity calculation rules of all kinds of factors on the 3D CAD model.Depending on the different size or meaning of the descriptor model,multi-mode retrieval program of common global retrieval,accurate global retrieval,and local feature retrieval was proposed for the size requirement of Model retrieval in different application scenarios.Finally,this paper verified the feasibility of the algorithm by searching a part of parts library.(4)3D CAD model retrieval system that oriented to the different stages of product design was achieved on the CAD software platform,which to reuse all types of the previous results designed.In the conceptual design phase of products,multi-condition of part properties combination retrieval based on semantic ontology was supported.In the detailed design stage,a fuzzy,precise retrieval for global or local model merged with process marking information was supported.The application of the above research results in the traction inverter product design of the Cooperative enterprise—Electric Co.,Ltd proved the feasibility and effectiveness of the retrieval methods.