基于层次分析法与定位确定性的工件定位方案规划算法

Design Algorithm of Workpiece Locating Scheme Based on Analytical Hierarchy Process and Locating Determination

结合层次分析法与定位基准选择的影响因素,构建定位基准选择的层次结构模型。两两比较各层因子的重要性后,利用标度法构造相邻两层的判断矩阵,反复验证判断矩阵的一致性,通过后判断矩阵的特征矢量可作为层权矢量。通过层权矢量的逐层相乘,所获得的组合权矢量即为定位基准选择的决策指标。考虑加工要求、工艺自由度与实际自由度之间的关系,将定位确定性等效为工艺自由度必须是实际自由度方程组的解,获得定位确定性的总体数目条件,作为定位方案设计过程中定位点数目够与不够的判断依据。同时,从工程应用的角度推导出定位确定性的局部数目条件,以确定定位基准上所布局的最少定位点数目。综合定位确定性的总体数目条件、局部数目条件以及定位基准的决策方法,构建定位方案的迭代规划算法。

With the consideration of analytical hierarchy process and effect factors of locating references, the hierarchy model is configured to select the locating reference. By comparing the importance of factors in all levels with each others, the judgement matrix between adjacent levels can be constructed by using the scaling method. Its eigenvector will be the level weight vector when the judgement matrix can successfully perform the consistency check. And then, the combination weight vector, which is obtained by multiplying all level weight vectors, can be a decision index of locating references. According to the relationship among the machining requirements, the technological degrees of freedom and the practical degrees of freedom, the locating determination can be equivalent to the fact that the technological degrees of freedom are the solutions for the equation set of the practical degrees of freedom such that the global number condition can be concluded to be the judgement criterion of enough locating points in the locating scheme. Simultaneously, the decision of the minimum locating points on locating reference can be made allow for the local number conditions which are achieved from viewpoint of engineering application. Thus, an iterative planning algorithm of locating scheme can be suggested according to the global and local number conditions of locating determination in combination with the decision method of locating reference.