Sampling point planning method for aero-engine blade profile based on CMM trigger probe

Abstract

In the digital measuring environment, to solve the problem of sampling point planning on the aero-engine blade profile, two requirements should be satisfied: adapting geometry features and keeping the sampling point spacing. Therefore, this paper proposes an adaptive sampling method, which can flexibly increase or decrease the sampling points according to the curvature. Firstly, according to the geometric characteristics of blade profile, an adaptive sampling method based on the equal moment theory is established. Secondly, a parameterized model based on non-uniform rational B-spline (NURBS) is used to represent the geometry of the blade profile, and the Hausdorff distance is used to evaluate the error of the fitting curve. Finally, two cases verify the effectiveness and accuracy of the proposed method. In the simulation, the relationship between the adaptability and the error of the proposed method is analyzed by taking the Sine function as an example. It is obtained by numerical calculations that the error reached the minimum when the adaptive degree r is 0.75. In the actual blade measurement experiment, compared with other methods, the deviation between the reconstructed blade cross-section curve by the proposed method and the theoretical curve is minimum.