Comprehensive calibration of robots and large machine tools using high precision laser-multilateration

Within this paper procedures for the high precision, flexible and comprehensive calibration of robots as well as large machine tools based on laser tracking interferometers will be presented. Four tracking interferometers, so called 'Lasertracers' from the etalon AG, are used. Herewith four length measurements with uncertainties of some micrometers between the Lasertracers and a single reference mirror fixed in the machine spindle or on the robot endeffector are performed simultaneously. The commercial software outputs the 3D absolute positions of the mirror with a measurement uncertainty of about 2 µm, depending on the realized application. Subsequent data processing procedures were developed to obtain different kinematic and dynamic machine properties which can be used for calibration. These properties include positioning accuracy, repeatability, straightness, squareness, uniformity of velocity, coaxiality and 3D circularity. Current research work focuses on the fast and precise identification of geometric and kinematic model parameters of different robots types and sizes.