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

摘要： 针对航空复杂产品装配过程中,多维装配偏差源间的非线性耦合作用会导致装配精度传递保持能力弱且可能发生极大装配超差的现象,提出一种基于概率法的装配过程精度保持性评价模型与方法。首先,分析装配偏差引起的应力作用,研究基于应力效应的多维装配偏差耦合聚焦超差效应,并以概率评价法为基础研究装配精度保持性;其次,采用大偏差原理中Gartner-Ellis定理分析装配过程极大超差问题的发生概率,建立融合偏差分析与大偏差原理的装配精度保持性评价概率模型;此后,利用动态滑动窗口法实现基于实测信息的超差概率计算,并以此结果为判据提出装配精度保持性的反馈调整措施。以某典型机翼盒段件为例,通过计算装配过程外形对缝间隙与阶差指标发生极大超差的概率,并借助装配超差预防优化系统实现装配过程的精确调整,提升装配质量约30%,增强了装配过程精度处于受控范围的能力。

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