07 Fakultät Konstruktions-, Produktions- und Fahrzeugtechnik
Permanent URI for this collectionhttps://elib.uni-stuttgart.de/handle/11682/8
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Item Open Access Walking without impacts as a motion/force control problem(1992) Blajer, Wojciech; Schiehlen, WernerThe paper deals with the synthesis of control for impactless bipedal walking. In order of avoid impulses, both the specified motion of the biped and its ground reactions are controlled, yielding a combined motion and force control problem. A method for modeling and solving such problems is proposed. and then illustrated by the example of an impactless planar walk of a seven-link bipedal robot. Some numerical results of the motion simulation are reported.Item Open Access A combined distance and surface profile measurement system for industrial applications : a european project(1994) Docchio, Franco; Perini, Umberto; Tiziani, Hans J.The paper reports the design, development and characterization of an electrooptical equipment suitable for distance measurements and three-dimensional gauging of surfaces of industrial interest. The equipment comprises a dual-wavelength heterodyne interferometer for absolute distance measurements with a range of 20 m and an accuracy of 0.1 mm, that is integrated with a macroscopic scale, adaptive profilometer for threedimensional measurement of the shape to 1 mm. The performance of the equipment is well suited for effective operation in industrial metrology. The equipment has been developed by three partners, namely the Dipartimento di Elettronica per I’Automarione of the University of Brescia, the Sezione Diagnostica Elettroottica of ClSE, Milan, and the lnstitut for technische Optik of the University of Stuttgart, in the framework of a European Project partially funded by the Community Bureau of Reference.Item Open Access Automatisch aufrüstbare Baukastenvorrichtungen für prismatische Werkstücke(1989) Heisel, Uwe; Thiel, W.Die Bereiche bei der flexiblen Fertigung von prismatischen Werkstücken, die von der Automatisierung bisher noch nicht erfaßt wurden, sind das Auf· und Abspannen der Werkstücke und das Auf-,Ab- und Umrüsten der Vorrichtungen. Diese Bereiche stellen somit eine Automatisierungslücke in der ansonsten automatisierten flexiblen Fertigung von prismatischen Werkstücken dar. So soll nun ein weiterer Bereich in den automatisierten Fertigungsablauf integriert werden.Item Open Access Phase shifting in an oblique incidence interferometer(1991) Boebel, Doris; Packroß, Bernd; Tiziani, Hans J.The evaluation of the interference pattern of a prism interferometer by a phase-stepping technique is described. The required phase shift is achieved by moving the surface under test perpendicular to the hypotenuse of the prism. Limits of this phase-shifting technique are discussed. A calibration method of the phase shift between the interferograms for the adjustable sensitivity of the interferometer is shown. Finally measurements of technical surfaces are presented.Item Open Access Determination of average roughness and profile autocorrelation width of metallic surfaces with a white light sensor(1984) Leonhardt, Klaus; Kaufmann, Ekkehart; Tiziani, Hans J.A new procedure to determine simultaneously a horizontal descriptor of the surface - the autocorrelation width - and the most important vertical descriptor - the root-mean-square roughness - is presented. It is based on the inversion of an analytic contrast formula. After a short introduction to white light random phase contrast measurement we describe the elimination process and show first experimental verifications.Item Open Access Contouring using two-wavelength electronic speckle pattern interferometry employing dual-beam illuminations(1992) Diao, Hongyan; Peng, Xiang; Zou, Yunlu; Tiziani, Hans J.; Chen, L.Es wird eine neue Konturing-Methode mit einer elektronischen Zweiwellenlängen-Speckle-Interferometrie (TWESPI) vorgeschlagen, bei der zwei Beleuchtungsstrahlen verwendet werden. Die optisch rauhe Oberfläche wird bei einer synthetischen längeren equivalenten Wellenlänge vermessen, so daß durch die Änderung der Wellenlängen eine variable Meßempfindlichkeit erhalten werden kann. Dadurch erweitert diese Technik den Meßbereich der Einwellen-Speckle-Interferometrie und erlaubt die Messung von Konturen steiler Profile als bisher mit der Einwellenlängen-Methode möglich war.Item Open Access Optimierung des Fahrverhaltens(1992) Langenbeck, Bernhard; Leister, Günter; Schiehlen, Werner; Kutzbach, Heinz-DieterDas Fahrverhalten von Traktoren wird durch eine Vielzahl von Konstruktionsparametern bestimmt. Durch gegenseitige Abhängigkeiten der Parameter gestaltet sich die Suche nach einer geeigneten Parameterkombination aufwendig. Ein Verfahren zur Optimierung von mechanischen Systemen, die durch Mehrkörpermodelle beschrieben werden können, wird auf das Fahrverhalten eines Traktors angewendet.Item Open Access Betrachtungen zum dynamischen Verhalten druckgeregelter Flügelzellenpumpen(1990) Heisel, Uwe; Fiebig, Wieslaw; Matten, NicholasZur Optimierung hydrostatischer Verdrängerpumpen wurde in den letzten Jahren verstärkt an Simulationsmodellen gearbeitet, die das dynamische Verhalten vorausbestimmen lassen. Während diese Simulation bei Zahnradpumpen und Axialkolbenpumpen gute Übereinstimmungen zwischen Rechnung und Messung ergibt, sind für druckgeregelte, einpolige Flügelzellenpumpen bisher keine geeigneten Modelle bekannt. Der vorliegende Aufsatz beschreibt die Vorgehensweise bei der Aufstellung eines dynamischen Simulationsmodells für einpolige Flügelzellenpumpen unter Berücksichtigung realer Randbedingungen.Item Open Access Basic regulatory principles of Escherichia coli's electron transport chain for varying oxygen conditions(2014) Henkel, Sebastian; Beek, Alexander ter; Steinsiek, Sonja; Stagge, Stefan; Bettenbrock, Katja; Teixeira de Mattos, M. Joost; Sauter, Thomas; Sawodny, Oliver; Ederer, MichaelFor adaptation between anaerobic, micro-aerobic and aerobic conditions Escherichia coli's metabolism and in particular its electron transport chain (ETC) is highly regulated. Although it is known that the global transcriptional regulators FNR and ArcA are involved in oxygen response it is unclear how they interplay in the regulation of ETC enzymes under micro-aerobic chemostat conditions. Also, there are diverse results which and how quinones (oxidised/reduced, ubiquinone/other quinones) are controlling the ArcBA two-component system. In the following a mathematical model of the E. coli ETC linked to basic modules for substrate uptake, fermentation product excretion and biomass formation is introduced. The kinetic modelling focusses on regulatory principles of the ETC for varying oxygen conditions in glucose-limited continuous cultures. The model is based on the balance of electron donation (glucose) and acceptance (oxygen or other acceptors). Also, it is able to account for different chemostat conditions due to changed substrate concentrations and dilution rates. The parameter identification process is divided into an estimation and a validation step based on previously published and new experimental data. The model shows that experimentally observed, qualitatively different behaviour of the ubiquinone redox state and the ArcA activity profile in the micro-aerobic range for different experimental conditions can emerge from a single network structure. The network structure features a strong feed-forward effect from the FNR regulatory system to the ArcBA regulatory system via a common control of the dehydrogenases of the ETC. The model supports the hypothesis that ubiquinone but not ubiquinol plays a key role in determining the activity of ArcBA in a glucose-limited chemostat at micro-aerobic conditions.Item Open Access Yb:CaF2 thin-disk laser(2014) Wentsch, Katrin Sarah; Weichelt, Birgit; Günster, Stefan; Druon, Frederic; Georges, Patrick; Abdou Ahmed, Marwan; Graf, ThomasWe present Ytterbium-doped CaF2 as a laser active material with good prospects for high-power operation in thin-disk laser configuration owing to its favorable thermal properties. Thanks to its broad emission bandwidth the material is also suitable for the generation of ultra-short pulses. The properties of the crystal as well as the challenges related to the coating, polishing, mounting and handling processes which are essential to achieve high power laser oscillation in thin-disk configuration are discussed. A wavelength tunability of 92 nm is demonstrated, which confirms the potential of Yb:CaF2 for the generation of ultra-short pulses. An output power of 250 W with an optical efficiency of ηopt = 47% was measured in CW multimode thin-disk laser operation with a pump spot diameter of 3.6 mm. Using a smaller pump spot diameter of 1 mm the fundamental mode output power was 13 W with an optical efficiency of ηopt = 34%.