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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
431

Spherically-actuated platform manipulator with passive prismatic joints

Nyzen, Ronald A. January 2002 (has links)
No description available.
432

Dynamics and controls for an omnidirectional robot

Henning, Timothy Paul January 2003 (has links)
No description available.
433

Realtidsmätning inom fastighetsbildning med "Precise Point Positioning" (PPP) / Real-time measurement in the real property with the "Precise Point Positioning" (PPP)

Kvarnström, Victor, Wallerström, Jessica January 2016 (has links)
Vid GNSS-positionering i samband med fastighetsbildningsåtgärder används vanligtvis den traditionella RTK-mätningen (Real-Time Kinematic) via SWEPOS nätverks-RTK-tjänst. Denna tjänst kräver mobiltelefontäckning eller motsvarande tvåvägskommunikation, vilket kan vara problematiskt inom områden med bristfällig mobiltelefontäckning. Under dessa förhållanden kan istället PPP-mätning (Precise Point Positioning) vara användbart vid fastighetsbildningsåtgärder då dessa tjänster tar emot korrektionsdata i realtid från satelliter. PPP kräver inte någon mobiltelefontäckning, däremot krävs en kommunikationslänk, en RTX-tjänst för att erhålla korrektioner externt från en RTX-satellit. Syftet med studien är att undersöka möjligheten till att nyttja PPP i realtid vid fastighetsbildningsåtgärder som ett alternativ till traditionell GNSS-mätning med nätverks-RTK. För att PPP ska vara ett alternativ till traditionell GNSS-mätning i realtid krävs det att mätosäkerhetskraven inom fastighetsbildning uppfylls. Mätosäkerheten undersöktes genom att utgå ifrån redan kända koordinater (RIX 95-punkter). Mätningarna har genomförts på fem olika platser i Sverige, Göteborg, Vänersborg, Karlstad, Torsby och Malung-Sälen. Mätdata som erhölls från undersökningsplatserna har analyserats samt jämförts med fastighetsbildningskraven. Resultatet av studien erhölls i form av analyserad mätdata med jämförelser mot redan kända (RIX 95) punkter. Avikelsen från känd RIX 95-punkt redovisas i resultatet utifrån tidsaspekten, den systematiska avvikelsen av translativ art, förändringar i avvikelsen från söder till norr samt utifrån två beräkningsmodeller, varav en translation och en transformation. För att få den erhållna mätdatan från RTX-tjänsten att överensstämma bättre med referenspunkten (RIX 95-punkten) togs beräkningsmodellerna fram för att möjliggöra modellering av systematiska avvikelser som uppkommit och därmed uppfylla kraven inom fasighetsbildningsåtgärder. Genom att ha analyserat och granskat olika samband har det framkommit att efter ca 20 minuters mätning, börjar precisionen för mätningarna att bli stabila. Utifrån resultatet är slutsatsen att PPP inte fungerar vid fastighetsbildningsåtgärder för områden inom stomnät, däremot fungerar metoden för skogs- och jordbruksfastigheter utanför stomnät. Förutsatt att en modellering genom translation alternativt transformation som är framtagen i denna studie används för att justera koordinaterna så fungerar PPP-mätning inom samtliga fastighetsbildningsåtgärder. Detta kräver då att mätdata erhålls efter 20 minuters mätning eller mer. / GNSS positioning in conjunction with the real property is usually used the traditional RTK measuring (Real-Time Kinematic) by SWEPOS network RTK service. This service requires mobile phone coverage or equivalent two-way communication, which can be problematic in areas with poor mobile phone coverage. Under these circumstances, PPP (Point Positioning Precise) could be more useful in real property measures when such services receives the correction data in real time from the satellites. PPP does not require any cell phone coverage, however it requires a communication link, a RTX service to obtain corrections externally from a RTX satellite. The purpose of the study is to examine the possibility of using PPP in real time at the real property as an alternative to traditional GNSS measurements with network RTK. The measurement uncertainty was investigated by starting out from already known coordinates (RIX 95 points). The measurements were performed out at five different locations in Sweden, Gothenburg, Vanersborg, Karlstad, Torsby and Malung-Salen. Measurement data obtained from the observations have been analyzed and compared with real property requirements. The results of the study were obtained in the form of data analyzed by comparison of the known (RIX 95) points. The deviation is known from RIX 95 point recognized in income based on the time factor, the bias of the translative case species, changes in deviation from south to north and from two calculation models, a translation and a transformation. To correct the measured values from the RTX service for a better match to the RIX 95 points calculation models were developed to facilitate the modeling of systematic deviations incurred and meet the demands of real property. Analyzing and examining various relationships have shown that after about 20 minutes of measuring, the precision of the measurements starts to become more stable. Based on the results, the conclusion is that the PPP does not work in real property areas within the core network, however, the method works for forestry and agricultural properties outside the core network. Assuming a modelling through translational alternative transformation, developed in this study is used to adjust the coordinates, the PPP measurement is working in all real property registration measures. This requires that the measurement data is obtained after 20 minutes of measurement or more.
434

Quantitative kinematic and thermal full fields measurement / Mesure quantitative de champs cinématiques et thermiques

Zhang, Chao 05 March 2019 (has links)
La mesure simultanée des champs cinématiques et thermiques est très importante pour les procédures thermomécaniques. Les caméras à base de silicium sont largement utilisées pour l'observation en temps réel des champs cinématiques, principalement grâce à la corrélation d'images numériques. De plus, ils sont aussi connus pour sa sensibilité dans le spectre du proche infrarouge, ce qui permet d’acquérir des champs thermiques à l’aide d’une caméra à base de silicium. Cependant, pour la caméra à base de silicium, il y a deux problèmes principaux d’obtenir simultanément des champs cinématiques et thermiques. D’abord, dans le spectre du proche infrarouge, une petite variation de température entraînera une modification importante du niveau de gris de l'image, ce qui entraînera facilement une mauvaise qualité des images. Deuxième, la corrélation d’images numériques nécessite une surface hétérogène et contrastée, tandis que la thermographie dans le proche infrarouge nécessite une surface homogène et constante. Dans cette thèse, une technique innovante a été proposée pour ajuster automatiquement le temps d'exposition de la caméra afin d'obtenir des images exploitables pour l’analyse cinématique et thermique, quel que soit l'évolution de température à la surface de l'objet observé. Cette technique a été validée par expériences différentes, notamment des expériences de chauffage d’un corps noir et des expériences de chauffage d’un échantillon réel. Les modèles radiométriques du corps noir et de la surface des échantillons calibrent respectivement. Basé sur les modèles radiométriques, des champs thermiques ont été reconstruits sur les images exploitables pour l’analyse cinématique et thermique. L'expérience à haute température est réalisée pour le ballonnement des tubes où les champs cinématiques et thermiques sont observés. La corrélation d'images numériques a été effectuée globalement afin d'obtenir des champs cinématiques. Pour effectuer la thermographie du proche infrarouge sur la surface de l’échantillon, le modèle radiométrique est étalonné selon une partie des pixels les plus brillants. Dans ce cas, 20% des pixels les plus brillants sont utilisés pour effectuer l'étalonnage des modèles radiométriques. Basée sur le modèle en utilisant 20% des pixels plus brillants, les champs thermiques sont reconstruits. Combiné avec les coordonnées connues du champ cinématique par corrélation d'images numériques, le champ thermique et le champ cinématique dans les mêmes coordonnées peut être obtenu. / Simultaneous measurement of kinematic and thermal full fields are very important for thermomechanical procedures. Silicon-based cameras are widely used to perform real-time observation of the kinematic fields, mainly thanks to digital image correlation. Moreover, they are known to be as well sensitive in the near-infrared spectral range, thus the acquirement of thermal fields using silicon-based cameras is possible. However, there are two main problems for the silicon-based camera to obtain simultaneously kinematic and thermal fields. One is that in the near-infrared spectral range, a small temperature variation will lead to a large modification in the image gray level, which easily leads to poor quality images. Another is that digital image correlation needs a heterogeneous and contrasting surface, while the near-infrared thermography needs a homogeneous and constant surface. In this thesis, an innovative technique was proposed to automatically adjust the exposure time of the camera to obtain kinematically and thermally exploitable images whatever the temperature evolution occurs on the surface of the observed object. This technique was validated by different experiments, including blackbody heating experiments and realistic specimen heating experiments. Radiometric models of blackbody and specimen surfaces ware calibrated respectively. Based on the radiometric models, thermal fields have been reconstructed on the kinematically and thermally exploitable images. High temperature tube ballooning experiment is conducted to perform both kinematic and thermal fields. Global digital image correlation was performed to obtain kinematic fields. To perform near-infrared thermography on the specimen surface, radiometric model is calibrated based on portions of the brightest pixels. In this case 20% of the brightest pixels are used to perform radiometric model calibration. Based on the radiometric model using 20% of the brightest pixels, the thermal fields are reconstructed. Combined with the known coordinates of kinematic fields by digital image correlation, the thermal fields at the same coordinates as kinematic fields can be obtained.
435

Nízkocyklová životnost v podmínkách jaderné energetiky / Low cycle fatigue research and application in nuclear industry

Sehnal, Dominik January 2019 (has links)
Fatique life extension of nuclear powerplants lies in the search for project reserves. This work deals with the evaluation of low-cycle fatigue of nuclear installations of the VVER type and the assessment of the influence of the computational model level. Fatigue tests of austenitic steel using optical method of digital image correlation for which the evaluation procedure is designed and used is performed. Selected model of plasticity with kimenatic (Chaboche) and combinated hardening (Chaboche, Voce) are calibrated from the obtained data. Subsequently, the durability of the test specimen is determined by computational modeling for different material models. From the comparison of the results of fatigue tests with the calculation, the material models suitable for the description of fatigue life and their validity are determined.
436

Polohování objektu ve 3D prostoru pomocí paralelního lanového robota / Object positioning in 3D space using parallel cable-driven robot

Rajnoha, Andrej January 2016 (has links)
At the beginning of this master’s thesis the definition of types of robots using parallel kinematics are presented, its possibilities of usage and current prototypes are described. The second chapter focuses on the proposal of robot construction and sizing electric and non-electric components of robot hardware. Derivation of direct and inverse transform mechanisms with creating flowcharts of their algorithms are stated in the two following chapters. The state machine controlled from user interface is then programmed based on these flowcharts. At the end of the work, cable-driven robot positioning accuracy is evaluated and platform workspace, together with motion and electric parameters, are measured.
437

Die kinematische und statische Analyse eines Biglide-Getriebes mit Hilfe der Programme Mathcad und GeoGebra / The kinematic and static analysis of a biglide mechanism using the programs Mathcad and GeoGebra

Kerle, Hanfried 07 June 2017 (has links) (PDF)
Der vorliegende Beitrag behandelt die kinematische und statische Analyse eines Biglide-Getriebes mit fünf Gliedern und zwei Schubantrieben zur Führung eines Punktes in der x-y-Ebene. Als mathematische Hilfsmittel werden die beiden Programme PTC Mathcad Prime 3.1 und GeoGebra 5.0 eingesetzt, die sich einander in hervorragender Weise ergänzen. Dabei ist Mathcad hier vorwiegend für Matrizenrechnungen und GeoGebra besonders anschaulich für geometrische Grundaufgaben mit Animationen zuständig. Die Effizienz der vorgestellten Algorithmen und Hilfsmittel wird anhand zweier Anwendungsbeispiele aufgezeigt.
438

Analýza a porovnání dřepů s činkou pomocí povrchové elektromyografie / Analysis and comparasion of squat exercise due to surface EMG

Orava, Boris January 2010 (has links)
ABSTRACT  Title of dissertation: Analysis and comparasion of squat exercise due to surface EMG  Objectives of dissertation: To measure and describe the structure involving specific muscles durring back squat, front squat and smith machine squat exercise.  Method: Surface EMG analysis and simple kinematic analysis.  Results: Activation of m. gluteus maximus was highest after the start of excentric movement. Main muscle working on the chase between the concentric and excentric movement was m. rectus femoris. Very similar timing and synergy were between m. erector spinae and m. biceps femoris. In this study was not higher activation of m. quadriceps femoris during front squat exercise, activation of m. gluteus maximus were also higher.  Key words: squat, strengthening, bar, front squat, back squat, Smith machine squat, bodybuilding, weightlifting, powerlifting, EMG analysis, kinematic analysis 6
439

Active tectonics of the Doruneh Fault : seismogenic behavior and geodynamic role / Tectonique active de la faille de Doruneh : comportement sismogénique et rôle géodynamique

Farbod, Yassaman 12 June 2012 (has links)
Ce travail de thèse porte sur la tectonique active du système de faille de Doruneh (DFS) situé au NE de l'Iran. Une approche combinée de géologie structurale, morpho-tectonique, géomorphologie quantitative et datation par des nucléides cosmogéniques 36Cl et 10Be nous a permis de décrire la cinématique ainsi que le rôle géodynamique du DFS dans le contexte de la collision Arabie-Eurasie.Le DFS comprend trois zones avec des caractéristiques structurales, géomorphologiques et cinématiques distinctes, (a) inverse-senestre pour la WFZ (Ouest) (b) purement senestre pour la CFZ (Centre) et (c) inverse pour l'EFZ (Est). Les âges d'abandon de trois générations de cônes alluviaux quaternaires ont été déterminés à ~12, ~36 et ~100 ka. Ces âges, combinés avec les décalages mesurés, indiquent une vitesse maximum de déplacement horizontal senestre de ~5,3 mm/an pour l'Holocène. Notre analyse d'aléa sismique indique que la longueur maximale d'un segment sismogène varie de 70 à 100 km, ce qui pourrait produire des séismes caractéristiques de magnitude 7.2 à 7.4 avec des intervalles de récurrence de ~750 ans.Nous proposons un nouveau modèle géodynamique dans lequel l'EFZ est impliquée dans une zone de cisaillement dextre d'orientation NNW entre Iran central et Eurasie. Le mouvement vers le nord de l'Iran central est accommodé dans cette zone de relais en transpression par du raccourcissement sur des failles inverses d'orientation NW, et transféré vers le Nord par des faille dextres d'orientation NNW. / This study focuses on the active tectonics of the Doruneh Fault System (DFS) in the north-eastern part of central Iran. A combined approach of geological and morphotectonic mapping, fault kinematic analysis, as well as in situ-produced cosmogenic dating (36Cl and 10Be) allowed us to characterize the active kinematics and geodynamic role of the DFS in the context of the Arabia-Eurasia collision.The DFS comprises Western, Central and Eastern fault zones (WFZ, CFZ, EFZ) with distinct structural, geomorphic and kinematic characteristics. The WFZ is oblique reverse-left-lateral, the CFZ is pure left-lateral and the EFZ is reverse. Exposure ages of ~12, ~36 and ~100 ka have been determined for three generations of alluvial fan abandonment surfaces along the DFS. Combining geomorphic offsets and their related ages yields a maximum left-lateral slip rate of ~5.3 mm/yr for the CFZ during Holocene. The maximum length of independent seismogenic fault segments varies from ~70 to ~100 km that could produce a characteristic earthquake with a magnitude of Mw =7.2 to 7.4 and recurrence interval of ~750 years.We propose a geodynamic model in which the EFZ is involved in a NNW-trending dextral shear zone between Central Iran and Eurasia. This implies that the EFZ forms a complex right-lateral transpressional relay zone between the eastern and northeastern Arabia-Eurasia convergence boundaries. The northward motion of Central Iran relative to Eurasia is accommodated by shortening on NW-trending reverse faults, and is transferred northward via NNW-trending dextral faults.
440

Kinematická analýza testů dynamické neuromuskulární stabilizace u osob s vertebrogenním onemocněním / Kinematic analysis dinamic neuromuscular stabilization tests in people with low back pain.

Burešová, Vendula January 2015 (has links)
The main target of this thesis was to detect objective changes in the implementation of four postural locomotor tests DNS and during walking. The movements were recorded using the optical MoCap - the kinematic analysis Qualisys. The particular interest of the investigation was to determine the current stabilization of the spine system in individual subjects aged 25 to 55 years, which was documented by means of the angular deflection of each segment, the flat segment deviation or the shift of the marker in a coordinate system. The measurement results were compared between ten individuals with LBP and ten persons without any difficulty who were placed into the control group. The data were collected using the software QTM and Visual3D and subsequently were statistically processed. A statistically significant difference was observed during walking when comparing the angular deflection of the pelvis to the chest at the rotation and lateroflexion (ř). The significant difference of the pelvis shift toward the chest during flexion and rotation (ř) was showed in a deep squat test, but the difference was not confirmed in lateroflexion (ř). Furthermore, no statistical difference of the lateral deflection of the same segment (pelvis or chest) (cm) in patients with LBP compared to all subjects during the...

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