Prediction Sampling Method And Probe Compensation Technology Of CMM Research

Different from the traditional design, reverse engineering is feedback information from manufacture to design. It gets related data of model with measuring equipment, then create CAD model with some technology. The core is the measurement of the geometry. With the rapid development of reverse engineering, as the supplement of hardware equipment, software technology is more and more important.The author did some works on sampling prediction method, hemisphere probe measurement and compensation, triangle mesh subdivision, spherical probe compensation of CMM. The author wrote some software interfaces to prove the study results with some examples. The main works and results are:(1) As for the low accuracy and low efficiency of the existing typical adaptive prediction method of measuring, this thesis proposed a method, tangent deflection prediction method. The method realizes sampling prediction by elements of direction and length. It is proved that this method is twice better than circular arc method in accuracy and efficiency, meanwhile sample point distribution is better.(2) Base on hemispherical probe measurement, this thesis proposes an efficient method that it automatically predicts hemisphere head measurement direction when measured grid free surface. The average error is 0.75 um by simulation of a saddle surface. The predicted method can promote measurement efficiency.(3) Based on a triangular mesh subdivision method with the measuring paths, this thesis optimizes grid distribution by extra lines average distribution between adjacent paths.(4) By combined this triangular mesh subdivision with average vector probe compensation, it is called online probe compensation and it is efficient. Compensation average error is 2.9 um of online method, while 4.3 um of Delaunay outline method by a simulation of a saddle surface. Online method can use with its efficiency and accuracy.