飞机大部件位姿调整的关键测量特征点误差控制权值计算方法

为了实现飞机大部件的最佳位姿调整,基于层次分析-误差评定组合方法,研究了一种应用于综合评估数字化装配中关键测量特征点的误差控制权值的计算方法。采用引入权值的最小二乘法求解大部件位姿调整量,提高装配精度。通过层次分析(AHP)方法确定关键测量特征点主观权值,误差评定法确定关键测量特征点客观权值,两者结合综合评定关键测量特征点权值。以最小装配误差为优化目标,利用权值实现多个关键测量特征点的误差分配优化。实例分析中,将超差的对接交点误差由1. 23 mm降低到了0. 72 mm,满足各个测量点的容差要求。以奇异值分解算法求解目标优化初值,采用牛顿法迭代求解,得到部件的最优位姿,并以中后机身对接为对象分析验证权值分配的合理性。

A Method for Calculating the Error Control Weight of Key Measurement Feature Points in Position and Pose Adjustment of Large Parts of Aircraft Components

To achieve the best assembly pose of large aircraft parts, a method of the analytic hierarchy process (AHP) combined with error evaluation is proposed, which can comprehensively evaluate the weights of key points in digital assembly and solve the problems of position and posture adjustments of large parts using the least square method with weight values to improve the assembly accuracy. The AHP and error assessment method determine the subjective and objective weights of key measurement feature points, respectively. The combination of these two methods is used to evaluate the weights comprehensively, with the minimum assembly error as the optimization goal. Weight allocation is applied to optimize the allocation of errors of several key points. In the case analysis, the error of the overdraft intersection point is reduced from 1.23 mm to 0.72 mm, which satisfies the tolerance requirement for each measurement point. The singular value decomposition algorithm is then used to calculate the initial value of the result and the Newton method is employed iteratively to obtain the optimal pose of the parts. The rationality of the weight distribution is verified through the measured data of mid-back fuselage docking.