GEOMETRIC CALIBRATION OF CMMs USING 3D LENGTH MEASUREMENTS

摘要

This paper presents a new calibration method for larger size co-ordinate measuring machines (CMMs). This method provides 21 parametric errors by performing 1-dimensional length measurements in the workspace of a CMM. A special measurement set up is realised, which enables automated volumetric error compensation of CMMs at their production stage. Located in a corner of the measuring volume, this laser set up performs multiple spatial linear interferometer measurements by movement of a CMM automatically. In this paper emphasis is placed on; ⅰ) automation of spatial laser interferometer measurements, ⅱ) minimising cosine errors by optimisation of the interferometer signal, ⅲ) measurement strategy and ⅳ) verification of the calibration.