Analysis, optimization and synthesis of compliant linkage mechanisms for ultra-precision applications

Prof. L. Zentner

Because of their advantages prismatic flexure hinges are used as material coherent revolute joints in compliant linkage mechanisms for ultra-precision applications. In this case the requirements for precision are in the order of nanometers or of angular sub seconds. Mostly flexure hinges with basic cut-out geometries like circular or corner-filleted contours are used. Therefore, compliant mechanisms based on these flexure hinges have limited motion range and path accuracy. In existing approaches, the number of joints is increased in the kinematic chain of the mechanism, while there are now studies on the optimization of the flexure hinge contour. This leads to a need for research on analysis, optimization and synthesis of compliant linkage mechanisms with specifically designed flexure hinges. Thus, necessary requirements for further steps like calibration, compensation and mathematical correction are provided.

The intention of this research project is to investigate the influence of the flexure hinge contour, the hinge dimensions and their orientation on the motion behavior of compliant linkage mechanism in comparison to the rigid-body model. Other design goals are the strength and the deformation behavior. In terms of these criteria identified suitable single notch contours should be analyzed in the compliant mechanism. In a second step, the notch contour is to be optimized directly in the mechanism with respect to more than one objective. Since there are further but not considered parameters concerning the replacement of the rigid-body mechanism with the compliant mechanism, these influences of the constructional realization should be investigated too. To verify the repeatability, macroscopic mechanisms should be investigated by measurement. Design guidelines are to be derived for the synthesis of compliant mechanisms based on a spatial functional model.

Regarding the known investigations, the planned research enhances the approach for the synthesis of plane and spatial compliant linkage mechanisms with optimized flexure hinges. The more accurate knowledge of the repeatable kinematic behavior can enhance the widespread use of optimized flexure hinges in macroscopic mechanism and further it can provide the motivation for optimizing in micro mechanics technology. Compared to current research issues, particularly the aim to increase both, the precision and the motion range of compliant mechanisms consisting of flexure hinges with a relatively low shape complexity is a new approach. In addition, the approaches to use different flexure hinge contours in one mechanism and to use asymmetric cut-out geometries are investigated for the first time.

• Linß, S.; Schorr, P.; Henning, S.; Zentner, L.: Contour-independent design equations for the calculation of the rotational properties of commonly used and polynomial flexure hinges. In: Proceedings of the 59th IWK, September 11th – 15th, Ilmenau Scientific Colloquium, Ilmenau, Germany, 2017 – URN: urn:nbn:de:gbv:ilm1-2017iwk-001:5
• Gräser, P.; Linß, S.; Zentner, L.; Theska, R.: On the influence of the flexure hinge orientation in planar compliant mechanisms for ultra-precision applications. In: Proceedings of the 59th IWK, September 11th – 15th, Ilmenau Scientific Colloquium, Ilmenau, Germany, 2017 – URN: urn:nbn:de:gbv:ilm1-2017iwk-090:9
• Linß, S., Schorr, P., Zentner, L.: General design equations for the rotational stiffness, maximal angular deflection and rotational precision of various notch flexure hinges. Mechanical Sciences. 8, 2017, S. 29–49 – DOI: 10.5194/ms-8-29-2017

• Gräser, P; Linß, S; Harfensteller, F.; Zentner, L; Theska, R: Large stroke ultra-precision planar stage based on compliant mechanisms with polynomial flexure hinge design. In: 17th International Conference of the European Society for Precision Engineering and Nanotechnology (euspen), May 29th - June 2nd 2017. Hannover, Germany, 2017, S. 107-108 – ISBN 978-0-9957751-0-7

• Gräser, P.; Linß, S.; Zentner, L.; Theska, R.: Design and Experimental Characterization of a Flexure Hinge-Based Parallel Four-Bar Mechanism for Precision Guides. In: Microactuators and Micromechanisms. Mechanisms and Machine Science 45, Springer International Publishing, Cham, 2017, S. 139-152 – DOI: 10.1007/978-3-319-45387-3_13
• Gräser, P; Linß, S; Zentner, L; Theska, R: Increasing the stroke of an ultra-precise compliant mechanism with optimised flexure hinge contours. In: 16th International Conference of the European Society for Precision Engineering and Nanotechnology (euspen), May 30th - June 3rd 2016. Nottingham, UK, 2016, S. 487-488 – ISBN 978-0-9566790-8-6
• Gräser, P.; Linß, S.; Zentner, L.; Theska, R.: Synthese und Untersuchung eines nachgiebigen Koppelmechanismus für Präzisionsführungen. In: Tagungsband Zweite IFToMM D-A-CH Conference 2016, 25. - 26. Februar 2016, Innsbruck. Universität Innsbruck, 2016, insges. 8 S.
• Linß, S.; Milojević, A.; Pavlović, N. D.; Zentner, L.: Synthesis of Compliant Mechanisms based on Goal-Oriented Design Guidelines for Prismatic Flexure Hinges with Polynomial Contours. In: The 14th IFToMM World Congress: Taipei, Taiwan, October 25-30, 2015, 6 S. – DOI: 10.6567/IFToMM.14TH.WC.PS10.008
• Linß, S.; Zentner, L.: FEM-Based Analysis of the Influence of Notch Contour and Scale on Flexure Hinge Design Goals. In: The 3rd International Conference Mechanical Engineering in XXI Century: Proceedings: 17. - 18. September 2015. Niš, Serbia, 2015, S. 283-286 – ISBN 978-86-6055-072-1
• Linß, S.: Ein Beitrag zur geometrischen Gestaltung und Optimierung prismatischer Festkörpergelenke in nachgiebigen Koppelmechanismen, Ilmenau : Univ.-Verl. Ilmenau, zugl. Diss., Ilmenau, Techn. Univ., 2015 – URN: urn:nbn:de:gbv:ilm1-2015000283
• Gräser, P.; Linß, S.; Zentner, L.; Theska, R.: Ultra-precise linear motion generated by means of compliant mechanisms. In: 15th International Conference of the European Society for Precision Engineering and Nanotechnology (euspen), 1 - 5 June 2015. Leuven, Belgium, 2015, S. 241-242 – ISBN 978-0-9566790-7-9
• Linß, S.; Opfermann, R.; Gräser, P.; Theska, R.; Zentner, L.: Nachgiebige Koppelmechanismen mit optimierten Festkörpergelenken für Präzisionsanwendungen. In: Tagungsband First IFToMM D-A-CH Conference 2015, 11. März 2015, Dortmund. Universität Duisburg-Essen, 2015, S. 79-85 – DOI: 10.17185/duepublico/37267
• Linß, S.; Milojević, A.; Zentner, L.: Considering the Design of the Flexure Hinge Contour for the Synthesis of Compliant Linkage Mechanisms. In: Shaping the future by engineering: 58th IWK, 8 - 12 September 2014; Proceedings. Ilmenau: Univ.-Bibliothek, ilmedia, 2014 – URN: urn:nbn:de:gbv:ilm1-2014iwk-033:4

TU Ilmenau - Compliant Systems Group 
- Project Coordination -
TU Ilmenau - Precision Engineering Group

08/2014 - 07/2017

DFG - Deutsche Forschungsgemeinschaft