Research On Tolerance Analysis Of The Integrated Transmission Device In Virtual Assembly

Integrated transmission is an important part of armored vehicle,of which assembly quality plays an important role in the overall performance of the vehicle.Virtual assembly technology has played an important role in guiding the integrated transmission assembly process simulation,assembly path planning and assembly sequence.However,at present the geometric models are still limited to idealized-dimension without tolerance information,which does not meet the actual assembly situation and analyze the assembly quality of the products when designers are using the technology.This paper will lay great emphasis on studying the virtual environment geometric tolerance expression and tolerance analysis method and relevant theoretical method on the basis of existing research results.The main contents are as follows:Tolerance information is introduced into the virtual assembly research.Based on the analysis model with tolerance information,a comprehensive product information model is provided.Tolerance model in virtual environment is realized,where the classification,content and realization method are discussed in detail.Based on the standardization of 3D specification,indication of 3D tolerance is obtained.The close relation among precise geometry,tolerance and indication of tolerance is founded to make sure the uniqueness and relevance of data,which provide the underlying model for tolerance analysis in the virtual assembly environment.Dimensional chain generation is an important basis for tolerance analysis.Combined the visualization and interactivity of virtual assembly environment,a generation method of dimension chain is provided based on human-computer interaction.Based on the characteristics of extreme value,probability method and Monte Carlo method,Halton sequence Quasi Monte Carlo tolerance analysis is proposed.Moreover,geometric tolerance is introduced into assembly tolerance analysis,and a set of guidelines for determining which geometric tolerance is put forward to analyze the impact on assembly tolerance.In order to assess tolerance design at the design stage,a new method of tolerance synthesis is put forward with the application of assembly process index,assembly success rate,over tolerance rate.As the validation and application of the above theory,Visual Studio 2010 is used in the framework of the platform VAAT,an initial tolerance analysis prototype system was developed to validate the theory and apply in the tolerance analysis.