A body in space has 6 degrees of freedom, 3 translational and 3 rotational (6DoF). For a linear positioning system, for example, 5 degrees of freedom are just distortions of the main linear movement. The calibration of the main movement and its 5 distortions is usually done using separate calibration setups and are rather extensive. The efficient, simultaneous measurement of all 6 degrees of freedom for small rotational angles is important for 3D nanostages having active rotational corrections such as those used for metrology-AFMs and Nano- Measuring-Machines. Especially demanding is the calibration of stages having large rotational ranges, such as hexapods and other parallel kinematic systems. Such systems are used for sample positioning in beam lines of accelerators and for nano-machining of parts in focussed ion beam systems (FIB). Today, position resolutions of a few nanometres are pos-sible. The attainable absolute position accuracy level, however, remains insufficient due to lacking calibration possibilities.
In this project METAS will develop new calibration methods for 6DoF positioning systems with rotation angles of several degrees and translations of several millimetres.
These new methods are based on high accuracy position determinations of three spheres in space by means of a micro- and a reference coordinate measuring machine. Such calibra-tions allow finally a full volumetric correction of the 6DoF stages.
This project is part of the European Metrology Research Programme (EMRP, http://www.euramet.org/index.php?id=emrp); it is partly funded by the European Union on the basis of Decision No 912/2009/EC.
