Dynamic and high precision sensor and tool positioning in large measuring volume with the aid of an inverse measurement concept - transfer project

• Applicants: Professor Dr.-Ing. Roland Füßl; Professor Dr.-Ing. Eberhard Manske
• Subject Area: Measurement Systems ; Automation, Mechatronics, Control Systems, Intelligent Technical Systems, Robotics
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 504463968

Increasingly large measurement objects and at the same time increasing demands on resolution and precision represent a current challenge in nanomeasurement technology. The global trend towards increasing precision in the nanometre range, greater complexity of structures to be measured in ever larger measuring and processing ranges of several hundred millimetres is unmistakable. The main driver is certainly nanolithography with an almost unimaginable market potential. The concept for a nanomeasuring machine that meets the requirements of these technological developments could be worked out within the framework of the DFG standard procedure "Dynamic and highly accurate sensor positioning in large measuring volumes using an inverse measuring concept". Furthermore, the scientific basics for the construction of such a large-volume nanopositioning and nanomeasuring system have been created. The large and heavy masses of the measuring object and the reference surface mirror are fixed in measuring machines according to the inverse concept, and a movable, fibre-optic-coupled, compact, interferometric sensor head realises the 3-dimensional precision measurement. This minimises the moving mass and enables high measurement dynamics. The inverse approach for the implementation of nanomeasuring machines is fundamentally new and opens up, on the one hand, the penetration of higher accuracy ranges and, on the other hand, the realisation of machines with very large ranges of motion. Through the interferometric measurement of six degrees of freedom, a minimal Abbe error is achieved. With a further six interferometer axes, the surface topography of the reference mirrors can be determined quasi-permanently, with nanometre precision in the machine itself. The great advantage of this approach is that any changes in the topography of the mirrors can be detected promptly and thus the correction matrices can be constantly updated. Based on the knowledge gained in the underlying DFG-project a prototype of a measuring machine based on the inverse concept is now to be developed within the framework of the transfer project together with the application partner SIOS Meßtechnik GmbH. In order to realise measuring times within an acceptable range despite large measuring objects and ranges of motion, the focus of the development is not only on the achievable precision but also on a high dynamic of the positioning. Furthermore, it is to be proven that the inverse concept can be realised in a significantly more compact manner, with greater long-term stability, provides better measurement uncertainty and, despite the large number of 12 laser axes (and two HeNe lasers in a master-slave configuration), can be manufactured significantly more economically than measuring machines according to the classic moving-stage principle. The final step is the metrological qualification of the measuring machine, the core of which is the verification of the achievable precision of the positioning.

• DFG Programme: Research Grants (Transfer Project)
• Application Partner: SIOS Meßtechnik GmbH