发动机叶片型面测量坐标系建立方法研究

发动机叶片的复杂外形结构和加工误差给叶片形位尺寸的精确高效测量带来很大困难。利用三坐标测量机对叶片的型面参数进行测量时,对于变形较大无法利用设计基准完成测量的截面,通过建立辅助测量坐标系的方法实现扫描。本文分析了建立辅助测量坐标系的原理,并提出一种利用四点拟合快速建立辅助坐标系的算法,将变形大的实测曲线与理论叶型进行迭代计算,从而大大减少计算时间。将该四点拟合法应用在大型扭转叶片的叶型测量中,在提高测量效率的同时,建立的辅助测量坐标系精确的实现了叶尖部分叶型的扫描,测量结果可靠。

Research on Establishment Method of Measuring Coordinate System for Engine Blade Profile

The complex shape structure and machining error of engine blade bring great difficulty to the accurate and efficient measurement of blade profile and size.When using CMM to measure the blade profile parameters,the auxiliary measuring coordinate system is established to scan the section that is too deformed to be measured in the design datum.In this paper,the principle of establishing the auxiliary measuring coordinate system is analyzed,and an algorithm named four-point fitting method to quickly establish the auxiliary coordinate system is proposed.In this algorithm,the measured curve with large deformation and the theoretical blade profile are calculated iterative-ly,which greatly reduced the calculation time.The measurement efficiency has been improved by using the four-point fitting method which is applied to the profile scanning of large torsion blade.The the blade tip section is accu-rately scanned in the auxiliary measuring coordinate system and the result is turned out to be reliable.