基于迭代算法的复杂曲面零件三坐标测量快速精确定位方法

针对复杂曲面零件在三坐标测量过程中存在着定位难、定位精度低的问题,基于改进的迭代最近点算法,提出了考虑半径补偿的预定位与精定位的多级定位算法；并通过建立定位点几何误差与叶片定位精度的数学关系模型,结合贪婪算法与六点原则,给出了近优的定位点序列生成方法。结合定位算法与定位点序列,给出了复杂曲面零件定位迭代流程,并开发了三坐标测量定位系统。以涡轮叶片为例,通过的定位仿真和定位实验,结果表明:该系统只需测量12～18个点即可使得叶片定位误差在0.1mm以内,证明该系统能有效的提高复杂曲面零件的定位精度和效率。 

Fast and accurate locating method forsculptured surfaces measured with coordinatemeasuring machines based on iterative algorithm

The blade is a typical part with sculptured surfaces, the locating of these parts for measurement with coordinate measuring machines (CMM) is a difficult and time-consuming task because there are no locating datum planes. To solve this problem, a multistage location algorithm including pre-location and fine-location, considering radius comprehension, was proposed based on iterative closest point algorithm. By establishing the relationship of locating errors and geometric errors of locating points, a near-optimal locating point sequence was generated using the greedy algorithm and six-point principle. Combining multi-stage location algorithm and locating point sequence, an iterative locating process for the part with sculptured surfaces measurement with CMM was researched and programmed. In the simulation and experiment of localizing a turbine blade with sculptured surfaces, only 12-18 points were need to maintain the location errors with in 0.1mm.The efficiency and accuracy of this method are desirable.