Laser Scanner-Based Robotic Coordinate Measuring Machine

Abstract

The objectives of the research presented in this paper are to design, integrate and demonstrate a robotic Coordinate Measuring Machine (CMM) for digitizing 3D geometries of objects to be used in reverse-engineering applications. The paper describes the mathematical model, the integration of the light detection and ranging (LiDAR) sensor with the automated positioning system and the programming used to attain the technology. The digital reconstruction of an object’s 3D model is achieved by applying forward robot kinematics along with homogeneous transforms to the point cloud detected by the LiDAR. The object’s geometric features are determined using 2nd-order polynomial best fitted curves of the scanned point clouds using the bisquare fit method. The CMM uses forward robot kinematics along with homogeneous transforms to programmatically compensate for geometric positioning errors resulting from deviations in position and orientation of the CMM components during assembly and from deviations in position and orientation of the workpiece when it is located in its mounting device. The instrument is shown to reconstruct with remarkable qualitative accuracy the 3D model of a turbine blade. Using a better-quality detecting sensor, the instrument can be used as well in automated quality control and inspection applications.