Georg Hein

This article presents the development of a novel, active measuring head for coordinate measuring machines that is capable of measuring forces and torques in six degrees of freedom (6 DoF) during tactile sensing. It uses a so-called flotor as carrier of the stylus, which is kept in levitation by six electromagnetic voice coil actuators (VCA) in an hexapod-like arrangement. These VCAs function simultaneously as actuators and as force sensors, which are calibrated in situ according to the Kibble balance principle. Additionally, a position and orientation measurement system is integrated, consisting of three two-dimensional position sensors that can detect the position and orientation of the flotor in 6 DoF. The article describes the basic functionality as well as the most important technical functional elements and key design features. These features aim to optimise the metrological properties of probing force and position measurement in order to achieve the lowest possible measurement uncertainty. Furthermore, the structure of the peripheral electronics system for the controlling of the coordinate measuring head is described. So far, the conceptual and structural design has been implemented, two prototypes have been manufactured and put into operation. At the time of publication, initial metrological investigations are being carried out.