Simulation medizinischer Implantate - Analyse fluidisch aktuierter Cochlea-Implantat-Elektrodenträger. - In: Conference proceedings, (2015), insges. 7 S.
The loss of hearing is a severe diagnosis among modern society. The Cochlear Implant, which is directly stimulating the auditory nerve from within the inner ear, has successfully proven its ability to overcome the communicational restrictions caused by sensorineural hearing loss. Efforts are made to enable cochlear implantation not only for deaf patients but for patients with residual hearing, in which case the residual hearing has to be preserved during surgery. In order to achieve this, the implants themselves as well as surgical techniques are improved. Within this work a compliant mechanism is combined with the electrode carrier of the Cochlear Implant, which includes the stimulation electrodes and is located inside the cochlea after implantation. This compliant mechanism is comprised of a non-stretchable thin fibre embedded into the wall of the silicone electrode carrier and a cylindrical inner cavity. This enables the implant to be fluid actuated, thereby fitting step by step the local curvature of the spiral shaped cochlea. Analysis of this functionality is performed to identify relevant geometrical and experimental parameters in preparation for production and testing of laboratory prototype in experimental setups.
Zur Mechanik vibrationsgetriebener Roboter für terrestrische und aquatische Lokomotion. - Ilmenau : Universitätsverlag Ilmenau, 2015. - Online-Ressource (PDF-Datei: XIX, 149 S., 11,82 MB) : Ilmenau, Techn. Univ., Diss., 2015
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Der Gegenstand der Arbeit ist die Mechanik von mobilen Robotern für terrestrische und aquatische Lokomotion. In den untersuchten Systemen wird die periodische Erregung eines inneren Antriebs durch nicht symmetrische Systemeigenschaften in eine gerichtete Fortbewegung gewandelt. Eine zweidimensionale Steuerbarkeit der Systeme wird durch frequenzabhängige mechanische Eigenschaften erreicht. Der Schwerpunkt der Arbeit liegt auf der mathematisch-mechanischen Beschreibung der Roboter mittels analytischer und numerischer Methoden sowie ihrer experimentellen Untersuchung. Prototypen mobiler Roboter dienen dem funktionellen Nachweis. Auf Basis von mechanischen Grundlagen werden terrestrische und aquatische Lokomotionsarten vorgestellt und klassifiziert. Mit Blick auf die praktische Realisierung von mobilen Robotern für unterschiedliche Umgebungsbedingungen werden Antriebssysteme in ihrer Eignung als Vibrationsquellen bewertet. Piezoelektrische Antriebe besitzen dabei besonderes Potential. Eine umfassende Analyse des Standes der Technik zeigt die Anwendbarkeit von vibrationsgetriebener Lokomotion für miniaturisierte technische Anwendungen. Systeme mit Borsten dienen der unidirektionalen terrestrischen Lokomotion. Mittels eines Mehrkörpersystemmodells und experimentellen Untersuchungen werden die verschiedenen Wirkungsmechanismen analysiert. Ein Prototyp für die Fortbewegung in Röhren wird vorgestellt. Für eine steuerbare zweidimensionale Lokomotion mit nur einem Antrieb müssen die Grenzen von klassischen Starrkörpersystemen überwunden werden. Der verfolgte Lösungsansatz nutzt das frequenzabhängige Schwingungsverhalten von elastischen Systemen, wie Balken oder Platten. Zur Untersuchung werden kontinuumsmechanische Modelle sowie Finite-Elemente-Methoden verwendet und durch experimentelle Untersuchungen erweitert. Die Erkenntnisse werden für die Entwicklung eines programmier- und fernsteuerbaren Prototyps benutzt. Sein Bewegungsverhalten kann durch die Änderung der Antriebsfrequenz auf verschiedenen Untergründen gesteuert werden. Das System erreicht Geschwindigkeiten bis 100 mm/s und kann das Fünffache seiner Masse transportieren. Abschließend wird ein innovativer Prototyp vorgestellt, der mit einem einzigen Antrieb eine steuerbare Lokomotion auf festem Untergrund und an der Oberfläche von Flüssigkeiten durchführen kann. Das terrestrische und aquatische Bewegungsverhalten wird untersucht und die Tragfähigkeit solcher Systeme auf Basis eines hydrostatischen Modells bestimmt.
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Electrical performance of electrically conductive silicone rubber in dependence on tensile load according to various parameters. - In: Microactuators and micromechanisms, ISBN 978-3-319-15861-7, (2015), S. 191-199
The paper presents the results of many investigations to make clear how the different parameters of tensile load which will possibly control the use of a strain sensor made of the conductive silicone rubber affect the electrical properties of this material. In order to clarify the behavior of this conductive silicone rubber during the cyclic load other tests are implemented on several specimens for each test to compare their behavior. The compliant systems with such sensors do not require mounting, and also they can be miniaturized. The target of these investigations is to use the conductive silicone rubber as a strain sensor by means of changing its electrical properties depending on the tensile load under different conditions.
Conception of a mechanical system for rehabilitation of hand function for use in medical training therapy. - In: Microactuators and micromechanisms, ISBN 978-3-319-15861-7, (2015), S. 143-158
A compliant mechanism as rocker arm with spring capability for precision engineering applications. - In: Microactuators and micromechanisms, ISBN 978-3-319-15861-7, (2015), S. 1-7
In precision engineering escapement and ratchet mechanism are often used to keep an element in a non-operating state e.g. in chronometers. Such mechanisms have a pivoted and spring-loaded pawl locking a ratchet. For miniaturized applications reducing the number of elements and functional integration is recommended. Spring clip mechanisms as rocker arms combine the rocker itself with a spring. Therefor a special formed wire is mounted in a frame by two shifted revolute joints. The spring capability is once determined by the geometry and the material and twice by the shifting of the axes and the deflection of the clip. In this contribution the force-deflection behavior of such mechanisms for different shiftings is focused utilizing the finite element method. Spring clip mechanisms realize a wide range of motion and due to a shifting of axes and the asymmetry the force-deflection behavior is influenced. Finally some precision engineering devices with a spring clip mechanism are suggested.
FEM-based analysis of the influence of notch contour and scale on flexure hinge design goals. - In: Proceedings, ISBN 978-86-6055-072-1, (2015), S. 283-286
Compliant mechanisms are state of the art in high-precise motion systems. Therefore, prismatic flexure hinges with mostly basic or rarely special designed cut-out geometries are used as revolute joints to realize an approximated rotation of a few degrees. Since flexure hinges are established in macro and also micro applications, the influence of scale has to be considered within the design process. In this paper, a finite elements method (FEM) model is introduced to investigate the three design goals maximum strain, shift of the rotation axis and deflection force in dependence of the notch contour and the scale. It will be shown that contour optimization is relevant for macro and micro applications, why design guidelines based on variable polynomial contours offer potential for microelectromechanical systems (MEMS).
A concept of adaptive compliant gripper with embedded actuators and sensors. - In: Proceedings, ISBN 978-86-6055-072-1, (2015), S. 263-266
Developing a gripper that can grasp objects of widely varying shapes represents a challenging task. Compliant mechanisms with embedded actuators and sensors are one way to obtain the gripper which could accommodate its grasping surface to any irregular and sensitive grasping object. This paper presents the concept of a new solution of adaptive compliant gripper finger with embedded actuators and sensors. Embedded actuators (within gripper finger structure) are able to morph shape of the grasping surface to accommodate different objects, while embedded sensors can provide information about the shape of an object that is grasp. Novel approach to the synthesis of compliant mechanisms with embedded actuators is also presented. It will be shown that gripper finger can achieve many complex grasping patterns.
Cooperation between the Ilmenau University of Technology and the University of Niš in "recent times" since 2008. - In: Proceedings, ISBN 978-86-6055-072-1, (2015), S. 251-254
Mechanical system for the rehabilitation of human hand function. - In: Proceedings, ISBN 978-86-6055-072-1, (2015), S. 3-6
Analysis and simulation of adaptive control strategies for uncertain bio-inspired sensor systems. - In: Mathematics in engineering, science and aerospace, ISSN 2041-3165, Bd. 6 (2015), 3, S. 567-588
We consider mechanical systems, that are not known precisely. In detail, we assume that the system parameters are unknown (uncertainty of system). Moreover, we allow for uncertainties with respect to perturbations from the environment (ground excitations). Such (non-linearly perturbed) systems need adaptive controllers which achieve a pre-defined control objective. Almost all known controllers offer the same drawback: (possibly unboundedly) monotonically increasing gain parameters. For application it is necessary to design improved adaptation laws. We present numerical simulations of several models primarily in application to a bio-inspired sensor model.