Research On Assembly Accuracy Prediction Method For Complex Product Assembly Process

In the assembly process of complex and precision products,due to the wide variety of components,complex and irregular assembly structures,and high assembly accuracy requirements for complex products,how to ensure that the final assembly accuracy of complex products meets the assembly function requirements has become an urgent need in current engineering.One of the problems solved.Starting from the actual engineering requirements of military complex mechanical products,this paper conducts research on the assembly accuracy prediction method oriented to the assembly process.The main research contents and results of the paper are as follows:(1)Study the design scheme of the assembly accuracy prediction system for the assembly process,discuss in detail the development environment,architecture,main functional modules,overall frame design and work flow of the system;study the assembly accuracy prediction mechanism for the assembly process,The process is divided into pre-assembly stage and actual assembly stage,and the assembly tasks to be completed in each stage are drawn up.(2)Research on the method of constructing assembly accuracy information model considering geometric tolerances,use small displacement vector theory to construct a screw model of typical geometric features,analyze the product assembly model layer by layer,establish dimensional tolerance units and assembly constraint units,and complete the alignment Pre-processing of assembly information unit.(3)Study the automatic generation and update method of the assembly dimension chain,based on the establishment of the assembly relationship transfer diagram,realize the automatic generation of the assembly dimension chain considering the sequence priority;study the update method of the assembly process dimensional chain for the actual assembly stage,and define The assembly process model is used to uniformly manage the accuracy information of the assembly process,and the assembly process dimensional chain is iteratively updated based on the assembly process model.(4)Research on the assembly accuracy prediction and deviation transmission analysis method based on the dimensional chain.On the basis of establishing the assembly dimensional chain,determine the assembly deviation transmission route based on the dimensional chain,and construct the equation for solving the assembly dimensional chain,and finally use the Monte Carlo statistical method Complete the calculation of the closed loop of the dimensional chain and the cumulative effect of the deviation.(5)On the basis of the above research,we independently developed an assembly accuracy prediction system for assembly process,which is mainly divided into three modules,including assembly accuracy information model preprocessing module,pre-assembly stage accuracy prediction module and actual assembly stage accuracy prediction module: Taking the selfdesigned internal structure model of products as an example,each module of the system was verified according to the overall workflow.Summarize the research work of this paper,analyze the problems existing in the research process of the subject,and look forward to the future work.