Double Precision Method and Data Registration Technology for Three-Dimensional Geometric Measurement

Abstract

In aerospace engineering, the structure and stress condition of a part is complex, which may affect the machining precision and quality. With a single measurement method, it is difficult to achieve effective evaluation of global geometry when performing high-precision measurements in local areas. Double precision measurement system and method were proposed in this paper. Two measuring instruments with different resolution and measuring range were selected for global and local geometric measurement. A rotation scanning measurement method with a line laser profilometer was proposed for local geometric measurement, which was suitable for on-machine precision measurement of a 3D workpiece morphology when the workpiece or motion stage is too large and the precision of the relative motion was not high enough. Error compensation model was established, and the measurement error was less than 3 μm. After multi-scale data registration, the hole error was reduced from 0.1 mm to 0.01 mm, and the hole center distance error  was reduced from 0.2506 mm to 0.0535 mm. Proposed method and system are effective for high efficiency precision measurement of global geometry while ensuring high precision measurement in target area.

Keywords: three dimensional geometric measurement, double precision, laser triangulation, error compensation, point cloud data registration