基于可行图的五轴在机测量探针轴向优化方法

针对不同探针轴向下红宝石球上触碰点会引入不同预行程误差导致标定精度和效率低的问题，提出了一种用于优化在机测量探针轴向的可行图构建方法。首先，根据包围盒算法计算各个测量点处免干涉的探针轴向。接着，利用机床运动学链建立红宝石球上触碰点与机床旋转轴的关系，进而构建机床转台旋转角度的可行图。为了提升检测精度，以减少红宝石球上触碰点和机床旋转轴方向变化为原则，优化测量路径上探针轴向，满足无干涉且红宝石球触碰点最少的条件。最后，以离心式叶轮为例进行验证，采用此方法不仅能保证红宝石球上触碰点个数最少而大幅度缩短标定时间，还能减少引入的机床误差量而提升测量精度，实验结果证明该方法重复性好、可行度高。

Stylus orientation optimization method in five-axis on-machine measurement based on feasible graph

Aiming at the problem that the contact points on ruby ball will lead to different pre-travel errors under different stylus orientations, leading to low calibration accuracy and efficiency, a feasible graph construction method for optimizing stylus orientation is proposed. Firstly, the interference-free stylus orientations at each to-be-measured point are calculated according to the bounding box algorithm. Then, the relationship between the touch positions on the ruby ball and the rotating axis of machine tool is established by using the kinematics chain of machine tool, and then the feasible graph of the rotary angle of the machine tool turntable is constructed. In order to improve the detection accuracy, the stylus orientation is optimized based on the principle of reducing the changes of the ruby ball contact positions and the direction of the machine tool rotary axis, so as to meet the conditions of interference-free and minimum ruby ball contact positions. Finally, the centrifugal impeller exemplifies that this method can not only ensure the least number of the touch positions and greatly shorten the calibration time but also reduce the introduced error of the machine tool and improve the measurement accuracy. The experimental results show that the method has good repeatability and feasibility.