| Popis: |
In dimensional metrology, the coordinate measuring machine (CMM) is the privileged tool using to control the mechanical part. To evaluate a form error of a spherical feature, discrete points are preleved on a feature to evaluates, the software of the machine fit a perfect geometric form to estimates a form error, least-squares fitting and minimum-zone fitting are two widely adopted algorithms to evaluate the form. Several methods for the evaluation of sphericity error have been proposed by different researchers. But when the feature is measured partially, the problem will be difficult, and an initial value must be introduced to the algorithm to ensure convergence to the solution. The proposed paper presents an efficient algorithm based on orthogonal distance regression (ODR) to estimates the parameters of the substitute sphere and the sphericity error. The model proposed tack into account the uncertainty of coordinates points. The obtained results are compared after to NIST reference values. |
