Measurement point layout strategy of free-form surface based on gridding using coordinate measuring machine

Abstract

The layout of measurement points is the key to the efficient inspection of free-form surfaces. Two algorithms are proposed for the layout of free-form surface measurement points: the free-form surface Gaussian curvature variation grid method and the isoparametric line curvature variation grid method. The former first divides the free-form surface into a uniform grid, determines the number of measurement points for each grid based on the change in the Gaussian curvature of each grid, and selects points within each grid based on a uniform distribution of the Gaussian curvature. The latter is achieved by first taking points from the curvature change on the initial U- and V-direction isoparametric lines, generating isoparametric lines from the points to divide the free-form surface into a grid, and selecting the grid intersections as measurement points. The effectiveness of the algorithm was verified by designing free-form surfaces, performing coordinate measuring machine (CMM) measurement experiments, and comparing the results with those of existing algorithms.

Keywords

• free-form surfaces
• measurement point layout
• cmm
• gaussian curvature
• isoparametric lines