Estimation of three-dimensional volumetric errors of machining centers by a tracking interferometer

• The tracking interferometer measures the target's position by the multilateration principle.
• The performance of the tracking interferometer prototype is experimentally investigated.
• The prototype's technical issues are discussed.
• Direct and indirect measurements of the machine's volumetric accuracy are compared.

A tracking interferometer is a laser interferometer with the mechanism to steer the laser direction to automatically follow a target retroreflector. This paper experimentally investigates the performance of the tracking interferometer prototype, developed by a part of the authors, in estimating the volumetric accuracy of a machining center based on the multilateration principle. Then, the prototype's technical issues are discussed based on the measurement uncertainty analysis. This paper briefly reviews the direct algorithm to calculate the three-dimensional position of the target, as well as the indirect algorithm to estimate geometric error parameters of the machine's kinematic model. Their comparison is also presented based on the uncertainty analysis.