Coordinate Measuring Machine Probe Radius Compensation And Its Application In Reverse Engineering

CMM is used in CAD/CAM, product testing and quality controlling in manufacturing widely for its metrical precision and strong intelligence. At the same time, CMM is often applied in RE as the main measure equipment for gathering sample data. The probe radius compensated is necessary when we measure by the CMM. It's discussed as an important problem in this thesis.Fist, Based on the analysis of the existing methods of the probe radius compensation, a new algorithm named "Four-Point Build a Sphere" is proposed. After expounding the theory of the algorithm and compensate process, the program is compiled by C++ to realize probe radius compensation. And aimed to the changes of conformance between the normal vector and compensated direction, we put forward a method named fixed normal vector based on the process of on-the-spot survey. This method improves the compensated formula.Then, the program is embedded into UG by UG/Open GRIP. Using this function, the operation speed and precision of the algorithm is analyzed elementarily by the computer simulation and how to improve the precision is introduced farther as well. Finally, using the algorithm and three-dimensional design function of UG, mouse surface is designed by the computer simulation to validate the theory and its application in UG further.All in all, it shows that Four-Point Build a Sphere is a better method of probe radius compensation. Its operation speed and precision can satisfy a majority of measure and has great application value.