TOUCH PROBE RADIUS COMPENSATION FOR COORDINATE MEASUREMENT USING KRIGING INTERPOLATION

Obtaining CAD (computer aided design) descriptions of actual parts hav ing complex surfaces is a key part of the process of reverse engineeri ng. This paper is concerned with the estimation of actual surfaces usi ng coordinate measuring machines fitted with a spherically tipped touc h probe. In particular, it addresses in detail the problem of probe ra dius compensation. A general mathematical model, using kriging, is pro posed which first generates the initial probe centre surface and then estimates the compensated or part surface. The compensation is achieve d using normal vectors to the initial probe centre surface at each mea sured point to compensate for the probe radius. The method is validate d experimentally on known and free-form surfaces.