Research On Surface Defect Repairing Method Of Vehicle Body Model Based On Engineering Scenarios

Body design appears to be a very complicated form of surface design,whose model quality has a serious impact on subsequent design,CAE and CAM,and whose model defects severely delay the design process,causing a lot of time and manpower.Although many commercial 3D model repair software has been developed.However,in terms of the design of body parts,the main repair method is still limited to manual repair of engineers.Existing repair software cannot meet the complexities and special quality requirements of the body design.Therefore,it is difficult for these software to obtain full trust of engineers.The most important reason for the above problems is that the car body surface model is a complex geometry composed of a large number of different types of surfaces combined in complex relationships and needs to meet relatively strict surface standards.Current mainstream repair tools,owing to the limitations of business models,tend to provide a solution that is fast,efficient,and purely geometric,yet lacks attention to the quality of repairs and new problems derived from that.Relatively speaking,the manual repair of engineers is more reasonable in terms of methodology.In the process of repairing a surface defect,an engineer first predicts the cause of surface defects and then uses targeted repair methods to achieve a final result through a series of iterations.Throughout the iterations,the engineer consistently evaluates the repair results according to the surface quality standards of the industry.Although manual repair is more logical and methodologically more efficient,the time and resources it wastes due to repeated manual iterations are significant.In view of the above issues,this paper attempts to construct an automated process that is similar in process and method to the manual repair method,and use similar evaluation indicators and modeling mechanisms to set up a parametric repair process.On the one hand,the parametric mechanism will provide the basis for future automated iterations based on complex quality assessment criteria.On the other hand,when the repair process is not ideal,the engineer can smoothly take over the repair results that require further adjustments,and quickly reach quality requirements through intuitive adjustment of key parameters.Based on the Siemens NX design software widely used in the automotive industry as a basic platform,this paper introduces knowledge engineering method,and completes a software prototype through secondary development techniques.The types of flaws in the car body surface model are complex.Due to time constraints,this article only focuses on the three typical types of gap defects in the car body model.A targeted automatic repair program is proposed and the corresponding software design and interactive interface are completed.The feasibility of the above concepts is verified by completing its automatic repair process.The practical application shows that this software is more targeted in engineering than the existing automated repair software and has obvious advantages in the repair of typical gap defects.At the same time,the engineer can also directly take over the repair process when the repair quality is not up to standards,and then quickly improve the surface quality by manually adjusting the parametric features.The measured results of a large number of complex car body surface models indicate that the introduction of engineering factors and the automation module that fully respect the engineer’s repair mechanism and repair method significantly improves the repair efficiency and repair quality of the model defects.