Blade profile extraction method based on blade profile measurement point cloud

Abstract

The invention discloses a blade profile extraction method based on blade profile measurement point cloud. Firstly, the invention studies a preprocessing method for improving profile reconstruction quality and speed, and the preprocessing method comprises a plurality of steps of segmentation, statistical filtering and simplification based on an octree structure. Secondly, the method includes researching a profile reconstruction method of a grid envelope, and performing spatial interpolation on a fixed-height blade profile to calculate accurate blade profile data; specifically, the method adoptsan outlier filtering method based on distance statistics to carry out data filtering, and includes preprocessing the point cloud data based on octree data structure point cloud simplification and other technologies; then, combining reconstruction algorithm based on region growth with a Delaunay criterion to realize rapid reconstruction of the blade point cloud; and finally, intersecting a plane with a specified height in a part drawing with a topological grid, and finishing extraction of blade profile data through spatial interpolation. The method is high in calculation efficiency, overcomesthe problem that the blade profile characteristics are difficult to accurately reserve in a projection method, and has a good engineering application prospect.

Description

technical field [0001] The invention belongs to the field of precision measurement, and in particular relates to a leaf shape extraction method based on a point cloud of blade surface measurement. Background technique [0002] Blades are a core component of aero-engines, accounting for about 30% of the entire engine manufacturing. The blade is a thin-walled part, and it works in harsh working conditions such as high load and complex force. In order to ensure its special performance, the airfoil profile is usually designed as a free-form surface, which has strict requirements on size and shape accuracy and strict surface integrity, and requires high manufacturing precision. The overall size span of the blade is large and the shape is complex, and processing such as casting or milling is easy to cause deformation. The quality of the blade has a great influence on the secondary flow loss of the engine, which directly determines its energy conversion efficiency. Therefore, it...

AI Technical Summary

Problems solved by technology

Discrete sampling of the blade profile can be realized by using optical scanning measurement, but due to the limitation of sampling density, it is difficult to ensure accurate acquisition of the profile data at the specified section of the blade (blade shape). The usual method is to take a certain height range near the blade section The point cloud is projected to obtain the point cloud data of the blade surface, and then the accurate leaf shape data is extracted

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