A geometrical work piece localization algorithm for rapid robot programming

摘要

When an offline programming method is employed for an industrial robot, accurate work piece localization is critical as there always exist discrepancies between the actual and nominal work piece locations. By drawing upon the mathematical tools from group theory and differential geometry, three fundamental error models (i.e., point-to-point, line-to-line, and plane-to-plane models) are formulated to describe the geometrical “distances” between two 3D models of the same work piece, which are obtained from the original CAD design and the in-situ measurement data, respectively. Consequently, the work piece localization becomes a 3D registration problem, i.e., to determine the optimal kinematic transformation between the two 3D models through minimizing their geometrical “distances”. Based on the proposed error models, a least-square algorithm is employed to iteratively identify the kinematic transformation parameters. Simulation results are provided to illustrate the effectiveness of the proposed algorithms.