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针对飞机多交点装配公差设计的多阶段决策特点,提出了基于动态规划的离散公差优化方法.首先,给出了典型的3交点和4交点装配协调误差表达式;然后,引入装配性能和成本指标,建立了公差设计的动态规划有向图模型,其中图节点表示可选的公差配合,并存储其后部子过程的最优装配性能和成本指标值,有向边表示相邻移形环节间的公差取值约束;最后,采用两阶段图遍历算法求解最优的公差设计,其中,“回溯”阶段逆序求解各节点和边的二元指标属性值,“前溯”阶段根据节点的二元指标属性值进行最优路径的启发式搜索.以某直升机尾梁及斜梁装配为例进行验证,结果表明该方法可求取公差的全局最优解,同时避免各环节成本和装配性能的重复计算、有效减小公差搜索空间、提高公差优化效率.
Aiming at the multi-stage decision-making characteristics of aircraft multi-intersection assembly tolerance design, a dynamic programming-based discrete tolerance optimization method is proposed.Firstly, the typical coordination expressions of three-point and four-point assembly are given.Finally, the assembly performance and cost index , A dynamic programming digraph model of tolerance design is established, in which the graph nodes represent the optional tolerance coordination, and store the optimal assembly performance and cost index values of the subsequent subprocesses. The directed edges represent the distance between adjacent transitional links Finally, we use the two-phase graph traversal algorithm to solve the optimal tolerance design, in which the “backtracking ” phase reversely solves the binary index attribute values of each node and edge, and the "backtracking Node binary attribute values of the optimal path of heuristic search to a helicopter tail beam and inclined beam assembly as an example to verify the results show that the method can obtain the global optimal solution tolerances while avoiding the cost of each link and Repeated calculation of assembly performance, effectively reduce the tolerance search space, improve tolerance optimization efficiency.