The kinematic analysis of the volumetric error measurement of a prismatic guideway based on six optical sensors and three diffraction gratings

A six degree of freedom encoder based on 3 optical gratings and six sensing elements was developed to measure the position as well as the volumetric deviations of a linear motion axis. In order to evaluate the performance of the device and in order to create a mathematical representation a kinematic model was developed. The kinematic models as well as the influence of geometric errors due to manufacturing and assembly are discussed.

Introduction

For the machine tool user, the importance lies in the overall accuracy of a machine, but it does not lie in the error of the individual components or the superposition of the individual errors. Therefore usually only the overall error of a machine tool is of importance to them. Most machine tool builders apply overall machine tool accuracy measurement tests in order to get lookup data that generates an overall accurate machine. With the increasing number of axis, this becomes harder. Therefore, the individual errors of the machine tool axis are of interest.