The Research Of Sculpture Surface Point Distribution Strategy And Error Evaluation Method

With the rapid development of modern manufacturing industry, diversification requirements on the parts contour structure are promoted, while requirements of the surface quality are correspondingly increased. Development of geometric measurement is promoted by high processing quality. Improvement of inspection quality and efficiency is directly affected by point distribution method and error evaluation algorithm. The point distribution strategy and error evaluation on sculpture surface are mainly studied in this paper.First of all, point distribution is studied based on surface processing sampling problems and a new method of sampling on curve and surface based on distance is approved. In view of curve-surface relationship, the method of point distribution on the curve is studied and then it is extended to address the issue of surface sampling. Curve is divided by initial measurement points according to processing requirement and then adaptive point distribution is achieved by refinement and iterative search. Adaptive point distribution on surface is realized by the method on combination of initial grid points and iterative points based on distance. Point density distribution can be varied with the change of surface curvature and surface topology information is effectively reflected.Then, error evaluation method on surface is studied. The objective function is set up using least square method. The initial conditions are optimized by the alignment of local coordinate system and points constraint constructed. Profile error evaluation is completed by using iterative closest point (ICP) algorithm, while six parameters relative to surface pose are optimized. In view of reference and surface forming theory, an approach is promoted for surface with large scope and curvature changed slowly. Firstly coordinates are projected, and then the minimum zone method for flatness solving is used.Finally, the algorithms mentioned are verified by simulation experiments. The adaptive point distribution on simulation surface is realized by the surface point distribution method based on distance. And the actual measuring points are simulated by adding error term. Then error evaluation is completed by ICP and projection method, respectively. The results of experiment show that the methods mentioned are effective and practical.