关键词: 装配精度保持性, 大偏差原理, 装配偏差耦合, 概率计算, 反馈调整

Abstract: Aiming at the phenomenon that weak assembly accuracy transmission retentivity caused by nonlinear coupling between multi-dimensional variation sources which may lead to extreme out-of-tolerance in the assembly process of complicated aviation products,an evaluation model and method of assembly process accuracy retentivity based on probability method was proposed.The stress effect caused by assembly variation was analyzed,the effect of multi-dimensional assembly variation coupling focusing caused out-of-tolerance based on stress effect was studied,and the assembly accuracy retentivity was discussed with the probability evaluation method.The occurrence probability of error out-of-tolerance problem in assembly process was analyzed by Gartner-Ellis theorem in large deviation principle,and the probability evaluation model of assembly accuracy retentivity based on the combination of variation analysis and large deviation principle was established.The dynamic sliding window method was proposed to solve the real-time out-of-tolerance probability,then the feedback adjustment measures were presented based on the probability results.Taking a typical wing box as an example,by calculating the probability of extreme out-of-tolerance for the target of gap and flush in assembly process,the accurate adjustment of the assembly process was realized with the assembly out-of-tolerance prevention and optimization system,and the assembly quality could be improved by about 30% and the assembly process accuracy could be guaranteed to be within the controlled range.

Key words: assembly accuracy retentivity, large deviation principle, assembly variation coupling, probability calculation, feedback adjustment