Abstract:

The aviation engine blade is the core component of high performance aero engine, the shape and the machining precision have great impact on its characteristics. Because of its working environment and functional requirements, the geometry shape of the blade was designed to be of variable cross-sections and high twist surfaces. One of the most important parameters to measure the blade geometry was the mean camber line. How to extract the mean camber line of blade accurately and efficiently was one of the problems to be solved urgently. Thus this paper combined MLS method and piecewise isometric curve principle to extract the mean line. This method first divided the engine blade section points into segments, and then the MLS method was applied to make the data of the blade much more intensive. Then, the piecewise isometric curve principal was used to extract the blade mean camber line. Besides, the algorithm accuracy was also evaluated, and the MLS algorithm was worked out when there were noises in the point cloud.

Key words: aviation engine blade, mean camber line extraction, piecewise isometric algorithm, moving least square(MLS)

摘要：

航空发动机叶片是高性能航空发动机的核心部件，其几何形状和加工精度对航空发动机的使用性能有很大影响。因其特殊的工作环境和功能要求，一般将其设计加工为变截面、强扭曲、薄壁曲面，其中弧线是表征其几何形状的重要参数之一，如何快速高效地提取叶片截面中弧线参数已成为航空叶片检测中亟待解决的关键问题。为此结合移动最小二乘法(MLS)提取中弧线，该方法首先将叶片二维截面点云进行分段处理，并通过带影响域的移动最小二乘对叶盆、叶背稀疏点进行加密，进而利用等距曲线原理提取航空叶片中弧线参数。同时就中弧线提取算法精度评价和噪声影响进行分析 。

关键词: 航空叶片, 中弧线提取, 分段等距曲线, 移动最小二乘