Calibration and Uncertainty of CMM based on Estimation of Geometric Errors.

This paper proposes a calibration method of CMM by estimating of geometric errors. In this calibration, well-known 18 geometric errors, namely parametric errors are adapted. And a rigid body error model using these parameters that indicates the behavior of deviation is described. Calibration can be conducted by estimating of those 18 parametric errors at each dispersed point in measuring volume. In order to estimate 18 parametric errors, independent 18 sets of measurements are necessary. So we designed a measurement strategy, 2D-artifact (ball plate) was arranged in several different positions and measured based on this strategy. As a result, 18 sets of parametric error curves are estimated separately. Considering the demand of uncertainty specification, ball plate uncertainty with traceabillity is reflected to the results of estimated parametric errors. That enables the calibration results to indicate the uncertainty.