This thesis is focused on the issue of computational modeling of soil harvesting while using the compact excavator from the company DOOSAN BOBCAT EMEA s.r.o.. The solution consists in creating two computational models in Rocky DEM and Ansys Mechanical. Rocky DEM software is used to solve the disconnection of soil by excavator components using the discrete element method. The outcome includes courses of forces and moments during the particular time of the individual joints of the model that was used. The obtained courses are then applied as an external load to the joint of a selected structural part of the analyzed model using a kinematic model in ANSYS Mechanical. The kinematic model consists of simplified geometry models of individual parts of the excavator arm, and a more detailed geometry model of the analyzed part of the arm. All the parts are connected to each other by rotational bonds representing joints. A static structural analysis of the mechanical stress is performed in ANSYS Mechanical for the prepared model during the simulated process. Finally, the selected structural part is assessed with respect to the elastic limit and fatigue strength.

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This thesis concentrates on the design of crank-type mechanism of engine with elongated expansion. The main attention is paid to examination of the progress of kinematic quantities and inertial forces in mechanism. Further on in the thesis, the analysis of piston-rod stress is carried out and is compared to the piston-rod of standard engine. In the last part of the thesis, there is an evaluation of advantages and disadvantages of the proposed mechanism solution.

This Master thesis deals with the design of linear unit with hydraulic actuator for the robot with parallel kinematic structure. One of the objectives is to get an overview of the differences related to characteristics of design and construction between serial and parallel kinematic structure (PKS) of the industrial robots, as a new type of technical objects in robotics. In addition the aim is to create an original structural design of linear unit, as the basic constructional assembly and operational node of robot with PKS, according to the specified input values, such as power, pressure, speed and stroke, important for the design of linear hydraulic actuator.

The master thesis deals with the engineering design and realization of a transtibial prosthesis for recreational in-line skating. The first part of thesis summarize background information about skating. The next part analyzes the kinematics of ankle joint based on gained information and own measurement by Motion capture method in Kinovea software. The thesis continues with realization of more versions of prosthesis followed by testing with patient. Finally, the thesis discus measured data.

This thesis deals with the design of a dynamic model of a harmonic drive. It includes a theoretical study aimed at the analysis of the harmonic drive gearing principle and its nonlinear properties. The first part of the practical section deals with the analytical calculation of the nondeformed geometry of the Flexspline. Based on these results, several simulations in ANSYS are created to identify torsional characteristics of a harmonic drive. These simulation models are further enhanced by the analysis of clearance, backlash and inaccuracies and their impact on torsional properties. By using MATLAB /Simulink, several dynamic submodels are created representing the individual characteristics of nonlinearities in harmonic drives. Furthermore, a comprehensive dynamic model is created of the mechatronic system which is describing all nonlinearities and kinematic error of the transmission. The dynamic model is also experimentally verified based on its damping properties.

Le travail s’intéresse aux effets de l’histoire de chargement sur le comportement et la durée de vie en fatigue de deux nuances (THYSSEN et CLI)d’un acier inoxydable austénitique 304L à la température ambiante. Les essais ont été réalisés en utilisant deux catégories d’éprouvettes. Les éprouvettes de la première catégorie (vierges) ont été soumises à des essais classiques de fatigue,alors que celles de la deuxième ont subi, avant les essais de fatigue, un pré-écrouissage monotone ou cyclique en déformation imposée. Les éprouvettes vierges manifestent un adoucissement cyclique suivi d’un durcissement cyclique alors que les éprouvettes pré-écrouies ne présentent qu’un durcissement cyclique. Les résultats montrent une grande influence du pré-écrouissage qui semble bénéfique en contrainte imposée, mais néfaste en déformation imposée,même en présence d'une contrainte moyenne de compression. Ces résultats sont discutés en termes d'évolution cyclique du module d'élasticité, des écrouissages isotropes et cinématiques, et de la densité d’énergie absorbées par cycle, dans différentes configurations : avec ou sans pré-écrouissage, en contrainte ou déformation imposées... / This study deals with the effect of the loading history on the cyclic behavior and the fatigue life of two kinds (THYSSEN and CLI) of 304L stainless steel at room temperature. The experiments have been performed using two specimens’ categories. The first one (virgin) has been submitted to only classical fatigue tests while in the second category, prior to the fatigue test, the specimen is subjected to a pre-hardening process under either monotonic or cyclic strain control. Cyclic softening followed by cyclic hardening are observed for the virgin specimens while only cyclic softening is exhibited by the pre-hardened specimens. The obtained results show that fatigue life is strongly influenced by the pre-hardening: it seems beneficial under stress control but detrimental under strain control, even in the presence of a compressive mean stress. The results are discussed regarding the cyclic evolution of the elastic modulus aswell as the isotropic and kinematic parts of the strain hardening, and strain energy density per cycle, in different configurations: with or without prehardening,stress or strain control...

Si de nombreuses études ont été consacrées à l’analyse des grands tours préparatoires aux sorties, aux sorties elles-mêmes et aux lâchers de barre en barre fixe ou barre supérieure de barres asymétriques, les éléments avec envol pour passer d’une barre à l’autre aux barres asymétriques (lâcher la barre inférieure pour saisir la barre supérieure ou l’inverse) n’ont, à notre connaissance, pas fait l’objet de telles études. Cette thèse de doctorat présente dans sa première partie une analyse cinématique du « pieds barre temps de ventre » ainsi qu’une analyse des moments cinétique et d’inertie mis en jeu par deux groupes de gymnastes, des expertes et des novices, lors de la réalisation de ce mouvement. La deuxième partie met en évidence des lois de contrôle moteur utilisées par les deux groupes pour réaliser l’élément. Afin de déterminer si les mouvements des deux groupes sont susceptibles d’améliorations et si la trajectoire créée au lâcher de la barre inférieure ou la gestuelle mise en jeu influence davantage la performance, une optimisation du pieds barre temps de ventre est proposée dans la troisième partie. Enfin, l’effet de l’introduction d’une loi de contrôle moteur dans le processus d’optimisation sur le réalisme des mouvements optimisés est envisagé. / Many studies were dedicated to the analysis of backward giant circles prior to release, releases itself or release-regrasp skills on high bar or uneven bars. To our knowledge, skills with flight phase to release low bar and regrasp high bar or the contrary were not studied yet. The first chapter of this doctoral thesis is dedicated to a kinematic analysis of the “counter movement forward in flight” on uneven bars and to the moment of inertia and angular momentum recorded for two groups of gymnasts performing this task: an expert group and a novice group. The second chapter highlights motor control laws used by the gymnasts of both groups. An optimization of the counter movement forward in flight was carried out in the third chapter in order to know if the movements of both groups may be improved and whether body mass center trajectory or body movements in flight most influence final performance. Effects of introducing a motor control law in the optimization process on the realism of optimized movements were studied.

Title of the thesis: Current concepts of double poling by classic technique in cross-country skiing Object of the thesis: The spatial-temporal analysis of node points and kinetic phases of the kick double poling and double poling of selected competitors at the FIS Nordic World Ski Championships in Liberec 2009. Method: A case study in which we used the kinematographic method for the analysis of the kick double poling and double poling of selected competitors. We analyzed the video of the 15-km classic in the FIS Nordic World Ski Championships in Liberec 2009. For the analysis we used the software APAS. Results: We performed spatial-temporal description of node points and kinetic phases of the kick double poling and double poling of selected competitors. We characterized current concepts of kick double poling technique, because selected competitors were relatively homogeneous set. By double poling we found out flexion-extension pattern in elbow, hip joints of slipping lower limb and partly in knee and ankle joints of slipping lower limb which results in generation of great propulsive force. Double poling becomes more significant driving element than push-off. Keywords: cross-country skiing, kick double poling, double poling, kinematic analysis, top competitors

In the study "The relationship between postural stability and physical activities", we focused on determining the level of postural stability and the possibility of influencing by appropriate means of exercise intervention in people with increased physical activity and persons with physical limitations. Persons with increased physical activity were top players and players competing in various sports (football, handball, volleyball, golf) and those with physical limitations, patients suffering from diseases that have a negative impact on postural stability (Friedrich's ataxia, autosomal dominant spinocerebellar ataxia, Charlot-Marie- Tooth). Upright posture in stance and movement is a fundamental prerequisite for human bipedal locomotion. Postural stability is the ability to maintain an upright posture, which advises the motor and coordination skills, and its meaning is close to equilibrium abilities. Maintaining an upright posture is ensured by muscle activity, which is controlled by the central nervous system based on information from internal and external environment. Control of postural stability is the primary prerequisite for successful movement and as such it can be developed on the basis of appropriate physical activities. All methods of measuring static and dynamic postural stability can be...