On the development and qualification of multiaxial designs of nanofabrication machines with ultra precision tool rotations. - In: Proceedings of the 19th International Conference of the European Society for Precision Engineering and Nanotechnology, (2019), S. 68-69
The majority of nanopositioning and nanomeasuring machines (NPMMs) are based on three independent linear movements in a Cartesian coordinate system with a repeatability in the nanometer range. This in combination with the specific nature of sensors and tools limits the addressable part geometries. This article contributes to the enhancement of multiaxial machine structures by the implementation of rotational movements while keeping the precision untouched. A parameter based dynamic evaluation system with quantifiable technological parameters has been set up and employed to identify general solution concepts and adequate substructures. It further on contains data based on comprehensive design catalogues, uncertainty calculations and CAD-model based footprint analysis for specific setups. First evaluations show high potential for sample scanning mode variants considering linear movements of the object in combination with angular movements of the tool, considering a goniometer setup in specific. Based on this, positioning systems for the tool rotation of a NPMM were selected and the positioning properties of different arrangements were determined in test series using autocollimators. General properties of the influence of the arrangement were derived. The arrangement of the substructures which fulfils the previous given requirements is integrated into the NPMM and investigated for long-term stability using a retroreflector as a tool and various laser interferometers. The influence of the additional positioning systems on the existing structure of NPMMs are investigated and solutions for the optimization of the overall system with regard to reproducibility and long-term stability are developed. For this purpose, comprehensive FEA simulations are carried out and structural adjustments are derived via topology optimizations. After all, the knowledge gained is formed into general rules for the verification and optimization of design solutions for multiaxial nanopositioning machines.
Measuring setup for the investigation of the reproducibility of tool changing interfaces for high-precision devices. - In: Proceedings of the 19th International Conference of the European Society for Precision Engineering and Nanotechnology, (2019), S. 172-173
High-precision devices such as the nanopositioning and nanomeasuring machines developed at Technische Universität Ilmenau are capable of measuring structures with nanometre precision. The machines are prepared for the use of different measuring tools, whereby the tool change has to be done manually. The reproducibility of the tool change is not sufficient to continue measuring without elaborate calibration. The extension of the machine capabilities for use in nanofabrication requires an automatic, highly reproducible tool change. A reproducibility of the changing interface of 30 nm is targeted. State of the art interfaces have a reproducibility which is one order of magnitude lower. To be able to measure the reproducibility in five DOF, an appropriate measuring method and setup are required. The required properties such as the measurement uncertainties are determined on the basis of these requirements. Measuring methods are compared, evaluated and selected systematically. The design of the measuring setup focuses particularly on minimizing disturbing temperature influences for the identification of function-determining influences of kinematic couplings. A vector-based uncertainty analysis is carried out to validate the setup.
Investigations of different compliant manipulator concepts for a high-precise rotational motion. - In: Proceedings of the 19th International Conference of the European Society for Precision Engineering and Nanotechnology, (2019), S. 64-67
Due to their advantages over conventional mechanisms, compliant mechanisms with notch flexure hinges are state of the art in precision engineering and micro systems technology. These compliant mechanisms are often used in positioning and adjustment applications with up to six degrees of freedom. In addition to the translational motions, as they are mainly required in linear tables and planar stages, also rotational motions are needed. For the realization of a high-precise rotation by compliant manipulators certain concepts with different complexity are existing. One approach is the use of flexure hinges with different geometrical parameters and notch shapes, which can be purposefully optimised depending on the requirements of the specific application. Another approach is the use of compliant mechanisms, in which the instantaneous centre of rotation represents the axis of rotation of the guided link either according to the remote centre of compliance concept or within the mechanism design space itself. In addition, a novel concept using a specific configuration of a four-bar mechanism, in which two adjacent links are of an equal length is presented in this contribution. The different approaches are compared by means of kinematic investigations and FEM-based simulations and the potential regarding a high-precise rotation with path deviations in the low micrometre range is shown.
Mechanical properties of an adjustable weighing cell. - In: Proceedings of the 19th International Conference of the European Society for Precision Engineering and Nanotechnology, (2019), S. 86-89
Tilt sensitivity modeling of a monolithic weighing cell structure. - In: Interdisciplinary applications of kinematics, (2019), S. 257-264
Optimization of compliant mechanisms by use of different polynomial flexure hinge contours. - In: Interdisciplinary applications of kinematics, (2019), S. 265-274
This paper presents the application of different polynomial flexure hinge contours in one compliant mechanism in order to increase both simultaneously the precision and the stroke of the output motion of compliant mechanisms. The contours of the flexure hinges are optimized in dependency of the required elasto-kinematic properties of the mechanism. This new approach for optimization is described in comparison to the use of identical common hinge contours. Based on previously optimized single polynomial flexure hinges, the validity of proposed guidelines is analyzed for a combination of several flexure hinges in two compliant mechanisms for linear point guidance. The rigid-body models of both mechanisms realize an approximated straight line as output motion. The compliant mechanisms are designed through the rigid-body replacement method and with different polynomial flexure hinges with orders varying from 2 to 16. The multi-criteria optimization is performed by use of non-linear FEM simulations. The derived values for the kinematic output parameters are compared for the ideal model and the optimized compliant mechanism. The results are discussed and conclusions for ongoing research work are drawn.
Compliant mechanisms for ultra-precise applications. - In: Interdisciplinary applications of kinematics, (2019), S. 249-256
This paper reports about enhanced compliant mechanisms with flexure hinge based on new analytic and/or FEM models that have been manufactured by state of the art wire EDM technology. Experimental proofs at test benches, equipped with ultra-precise interferometer based length and angular measurement systems, show first time the residual deviation to the intended path of motion with a resolution of nanometers/arc seconds. Theoretically determined and measured data are in good correlation. Repeatability limitations are rather more given by the residual noise of the overall test arrangement and mainly not by the mechanism itself.
Development of a changing interfacefor tools in nanofabrication machines with a highly reproducible position definition :
Entwicklung einer Wechselschnittstelle für Tools in Nanofabrikationsmaschinen mit hochreproduzierbarer Lagedefinition. - In: 5. IFToMM D-A-CH Konferenz 2019, (2019), S. 90-93
Im Stand der Forschung sind Wechselschnittstellen für Sensoren und Werkzeuge bereits in unterschiedlichen Maschinenklassen zu finden. Diese erfüllen jedoch nicht die geforderten höchsten Ansprüche an die Reproduzierbarkeit der Position für den Einsatz in Nanofabrikationsmaschinen. Kinematische Kopplungen zeigen aufgrund ihrer eindeutigen, kinematisch bestimmten Lagedefinition und einer hohen Reproduzierbarkeit eine gute Eignung für den Einsatz als Wechselschnittstelle in Nanofabrikationsmaschinen. Anhand von analytischen Berechnungen werden die wirkenden Kräfte und Verformungen der Koppelpunkte ermittelt. Für die Integration einer Justierung werden neue Anordnungen einer solchen kinematischen Kopplung untersucht. Da analytische und numerische Modelle die Reproduzierbarkeit nicht ausreichend genau abbilden können, wird ein geeigneter Messaufbau entwickelt. Dessen Eignung wird anhand einer dreidimensionalen, vektorbasierten Unsicherheitsanalyse nachgewiesen. Anschließend wird mittels der Ergebnisse der untersuchten Prototypen ein Modell zur Beschreibung des Zusammenhangs zwischen Konstruktionsmerkmalen und Reproduzierbarkeit entwickelt.
https://duepublico.uni-duisburg-essen.de/servlets/DocumentServlet?id=48214
Untersuchung von Umlenkelementen zur Anwendung in der interferometrischen Längenmesstechnik. - Ilmenau : Universitätsverlag Ilmenau, 2019. - 1 Online-Ressource (176 Seiten). - (Berichte aus dem Institut für Maschinen- und Gerätekonstruktion (IMGK) ; Band 33)
Technische Universität Ilmenau, Dissertation 2018
Aufgrund ihrer hohen Auflösung in Kombination mit einem großen Messbereich nehmen Interferometer eine Spitzenrolle in der Präzisionslängenmesstechnik ein. Sie müssen stets so angeordnet werden, dass der Messstrahl das Messobjekt auf geradem, unabgeschattetem Weg erreicht. Durch eine Umlenkung und Faltung des Interferometermessstrahls lassen sich Flexibilität des Aufbaus und Zugänglichkeit des Messobjektes verbessern. Diese Arbeit untersucht den Einsatz von Strahlumlenkelementen in interferometrischen Messanordnungen sowie die dadurch entstehenden Messfehler und Möglichkeiten ihrer Kompensation und Korrektur. Zunächst wird das grundlegende Messprinzip von interferometrischen Längenmessungen vorgestellt sowie auf mögliche Fehlerquellen insbesondere im Hinblick auf Strahlumlenkung hingewiesen. Es wird untersucht, wie sich die Änderung von geometrischen und Polarisationseigenschaften des Messstrahls durch ein Umlenkelement auf die interferometrische Messung auswirken. In dieser Arbeit werden verschiedene Modelle vorgestellt, mit denen die Lichtausbreitung und Polarisation sowie das geometrische Übertragungsverhalten von Umlenkelementen untersucht werden können. An Beispielen werden Einflussfaktoren herausgestellt, die auf die Polarisation des Lichtes wirken. Darüber hinaus wird deren Nutzung zur Kompensation von unerwünschten Polarisationsänderungen diskutiert. Eine Übersicht teilt reflektierende und refraktive Umlenkelemente auf Basis von Gemeinsamkeiten in Geometrie und Übertragungsverhalten in Kategorien ein. Der Fokus liegt dabei auf Invarianzachsen für Translation und Rotation der Elemente. Diese erlauben eine Bewegung der Umlenkelemente, ohne dass die untersuchte Funktionsgröße beeinflusst wird. Auf die Existenz und Lage dieser Achsen wird für jede Gruppe von Umlenkelementen hingewiesen. Zusätzlich erfolgt der Nachweis im Experiment, der das qualitative Übertragungsverhalten ausgewählter Umlenkelemente bestätigt. Schließlich werden die Erkenntnisse dieser Arbeit in Gestaltungsrichtlinien zusammengefasst, die den Anwender bei der Auslegung von Umlenkelementen für interferometrische Längenmesssysteme unterstützen.
https://nbn-resolving.org/urn:nbn:de:gbv:ilm1-2018000555
A method for the evaluation of the response of torque transducers to dynamic load profiles. - In: Acta IMEKO, ISSN 2221-870X, Bd. 8 (2019), 1, S. 13-18
http://dx.doi.org/10.21014/acta_imeko.v8i1.654