Abstract: In the forming of three-dimensional surface, there is shape error between the formed workpiece and the objective model due to springback and positioning error. By measuring the formed surface point cloud data by laser measurement, reconstructing the surface mode by robust least squares surface reconstruction, using a improved iterative corresponding point (ICP) algorithm to matching the reconstructed surface model and the original surface model, then calculates the form error of 3D sheet metal plate. Correct the forming error on the base of feedback of forming error many times by the multi-point closed-loop forming technology to eliminate forming error caused by springback and location, make workpiece surface unloaded consistent with original surface model, to complete the precision control in three-dimensional sheet metal forming. The simulation process of multi-point closed-loop forming control technology is given, research on key technology of surface reconstruction and registration in process of precision control in three-dimensional sheet metal forming, through the precision control experiments of cranioplasty prosthesis to verify the effectiveness of the method.

Key words: 3D sheet metal forming, Improved iterative corresponding point algorithm, Precision control, Surface reconstruction