Parameter Calibration And Measuring Points Planing Of The Flexible CMM

In recent years, the flexible coordinate measuring machines have become the hot topics of the coordinate measuring machines (CMMs), as they are characterrized by small volume, simple structure, portability, wide measuring range, low cost and on-line measurement, etc. A flexible coordinate measuring machine is specially designed for inspecting impeller in the project. The REVOTM system was used which is produced by RENISHAW. It is a revolutionary product designed to maxinise measurement throughput whilst maintaining high system accuracy. And then the machine could improve the accuracy and the speed. The following work has being done in the paper:1. Analysing the mechanical structure of the flexible coordinate measuring machine, the coordinate system was built according to the D-H methd which is widely used in the industrial robot. And the mathernatical model was got which is proved to be correct by graphic method. Finally, the measuring range of the REVOTM is analyzed.2. According to the characteristics of the system, the structural parameter errors were analyzed, and the error model was built. And then Gauss-Newton method and Levenberg-Marquarat method are introduced which are two algorithms of nonlinear least square method. Finally, the calibrations based on the distance model and the single point model were simulated by using Levenberg-Marquarat method. It is a basis for improving the accuracy of the flexible CMM.3. Firstly, the cross-sections were obtained by specifying a series of the blade. According to the distribution principle of measuring points, the points were planned based on the equal parameter method and the chordal tolerance method. It is realized by using UG/Open GRIP which is one of the UG second development tools. The results show that the points created by the chordal tolerance methd are much denser at the small curvature.