基于区间层次分析法的三坐标测量机精度分配方法

Accuracy allocation method of coordinate measuring machine based on interval analytic hierarchy process

为了提高三坐标测量机(CMM)研发和整机精度设计水平,提出了一种基于区间层次分析法的CMM精度分配方法。首先建立CMM准刚体模型;基于CMM目标精度和行程范围,利用套索算法(LASSO)和正交三角分解对准刚体模型进行全参数、高精度求解,得到CMM的21项几何误差。然后根据CMM结构和运动方式,划分CMM整机的精度层次结构;利用区间层次分析法确定CMM关键零部件相对于几何误差的精度分配权重向量。利用CMM 21项几何误差和精度分配权重向量得到CMM关键零部件的精度分配结果。结果表明,针对目标精度为(4.5+L/400)μm的CMM,利用精度分配方法组装的样机精度达到(2.7+L/400)μm。因此所提出的CMM精度分配方法能够更精确的对CMM关键零部件的精度选取提供依据,提高整机精度,节约整机设计效率,降低研发成本。

To improve the development of coordinate measuring machine(CMM)and the whole machine accuracy design level,a CMM accuracy assignment method based on interval hierarchical analysis is proposed.First,the CMM quasi-rigid body model is formulated.Based on CMM target accuracy and travel range,full-parameter,high-precision solution of the quasi-rigid body model using the least absolute shrinkage and selection operator(LASSO)and orthogonal trigonometric decomposition,the 21 geometric errors of the CMM are achieved.Then,according to the CMM structure and movement,the accuracy hierarchy of the CMM whole machine is divided.The interval hierarchical analysis is used to determine the accuracy assignment weight vector of CMM critical parts relative to geometric errors.The accuracy assignment results of CMM key components are obtained by using the CMM with the 21 geometric errors and the accuracy assignment weight vector.The results show that,for a CMM with a target accuracy of(4.5+L/400)μm,the prototype assembled using the proposed accuracy allocation method achieves an accuracy of(2.7+L/400)μm.Therefore,the proposed CMM accuracy allocation method can provide a more accurate basis for the accuracy selection of key CMM components.The accuracy of the whole machine is improved,the efficiency of the whole machine design is saved,and the research and development cost are reduced.