Research On Automatic Dimensioning Of The Shaft Parts Drawing Based On CBR

Dimensioning of drawings is a time-consuming and laborious task,but it is one of the important work contents in the part design and production process.It is expected to realize automatic dimensioning by applying the previous dimensioning experience.Main contents in the thesis: The automatic dimensioning system is designed by using CBR technology,the development of AutoCAD technology and c# language.According to the demand analysis,the overall implementation of the system is divided into three parts: the case library creation module,the case drawing retrieval module and the case reasoning dimensioning module.Firstly,the case graphic file library is established,and the object-oriented programming technology is applied to realize the redefinition coding of the primitive,and the knowledge representation of the case graphic is designed as a mapping set of the primitive objects and dimensioning objects.In the retrieval case stage,the case graph is decomposed into a combination of independent primitives and simple graphics,and a graph similarity calculation method is given to retrieve a case graph most similar to the target graph from the case library.The similar case graph retrieved is regarded as a collection of primitive objects and dimensioning objects mappings,and the target graphics are also regarded as a collection of primitive objects,and the mapping of similar primitive objects in the similar graphics is used to determine that the primitive objects in target graphics which need to be added dimensioning.Finally,the definition of dimension class and its derived class in.NET is used to create the annotation entity,and the redundant dimensioning is removed,the global dimensioning is laid out,and the system implements the automatic dimensioning function.The research on the automatic dimensioning of drawings based on CBR technology is only in the preliminary exploration stage,The knowledge representation method of case drawings and the inference dimensioning method designed in this paper can realize the automatic dimensioning function of the shaft through the AutoCAD platform,which improves the drawing efficiency to some extent.The example test results of the system show that it is reasonable and feasible to apply CBR technology to the automatic dimensioning technology.