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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.
1

Závislost parametrů lokomoce na tělesné výšce dospělé osoby. / Dependance of the gait parameters on a stature of an adult

Maštalková, Petra January 2014 (has links)
Title: Dependance of the gait parameters on a stature of an adult Objectives: The main aim of this study is to find out how the gait parameters depends on a stature of an adult. Another aim of this study is to compare these parameters between group of men and group of women. Methods: This thesis is type of descriptive - association research. In the practical part was used method of comparison for locomotion of people. As an objectification method was chosen 3D kinematic analysis of gait, which was performed using the Qualisys. Results: It was found that the dependence on a stature subject to the step length, pelvic rotation, flexion of a front knee, frequency and walking speed. Linear dependence on a stature is not subject to the the angle between femurs and flexion of a back knee. It was also found that the values of parameters which have the highest rate of variability reach a relatively low angular values. These parameters include the angle of rotation of a pelvis and the angle of flexion of a front knee. Opposite qualities shows the angle between femurs, which reaches the highest value, but clearly has the lowest rate of variability. Keywords: gait, footstep lenght, double support, stature
2

Optimization-based dynamic simulation of human jogging motion

Patwardhan, Kaustubh Anil 01 May 2015 (has links)
Mathematical modeling and realistic human simulation of human jogging motion is a very challenging problem. Majority of the current literature is focused on studying walking or running. This work is aimed at bridging the gap in literature due to the lack of research work in three main areas: (1) simulations and experiments on running at speeds lower than 3 m/s, (2) Kinetics of fore-foot strike pattern in jogging and running and (3) the existence of a double support phase in running at slower speeds and its effects. Formulations to simulate natural human jogging are studied and developed. The digital human model used for this work includes 55 degrees of freedom, 6 for global translation and rotation and 49 for the revolute joints to represent the kinematics of the body. Predictive Dynamics methodology is used for dynamic analysis where the problem is formulated as a nonlinear optimization problem. Both, displacement and forces are considered as unknowns and identified by solving the optimization problem. The equations of motion are satisfied by applying them as equality constraints in the formulation. Kinematics analysis of the mechanical system is performed using the Denavit-Haretneberg (DH) method. The zero moment point (ZMP) condition is satisfied during the ground contact phase to achieve dynamic stability. The joint angle profiles are discretized using B-spline interpolation method. The joint torque squared, also termed dynamic effort, and the difference between predicted motion and motion capture data are used as performance measures and minimized in the optimization formulation. The formulation also includes a set of constraints to simulate natural jogging motion. Two formulations are discussed for jogging on a straight path: (1) one-step jogging formulation and (2) one-stride jogging formulation. The one-stride formulation is discussed for clock-wise and counter clock-wise jogging along a curved path. Cause and effect is shown by obtaining simulation results for different loading conditions. The proposed formulation provides realistic human jogging motion and is very robust.
3

Contribution à l'étude de la marche d'un bipède

Miossec, Sylvain 27 November 2004 (has links) (PDF)
Ce travail est consacré à l'étude de la marche d'un robot bipède non actionné au niveau des chevilles. Les mouvements du robot sont réduits au plan sagittal. La spécificité de l'étude actuelle est la prise en compte d'une phase de double support sur actionnée, en plus de la phase de simple support sous-actionnée. Ce travail traite de trois points distincts. Il traite d'abord de l'étude de l'impact du pied libre avec le sol, dans les cas avec et sans pieds. Nous avons trouvé qu'avec le modèle d'impact utilisé le seul moyen d'obtenir un double support était d'éviter l'impact. Cette étude nous a également amené à remettre en cause les hypothèses généralement faites qui conduisent au modèle d'impact que nous avons utilisé, dans le cas où des contacts ont déjà lieu au moment de l'impact. Il traite ensuite de la génération de mouvements de marche que nous avons posée rigoureusement sous la forme d'un problème d'optimisation avec une hiérarchie de contraintes. Cette hiérarchie de contraintes consiste en une suite de contraintes où une contrainte doit être vérifiées pour que les contraintes suivantes soient définies. Une adaptation de programmes d'optimisation existants a été développée afin de tenir compte des spécificités du problème de la génération de mouvements qui a été posé. Le calcul du gradient de manière analytique a également été développé afin d'améliorer le déroulement du processus d'optimisation. Enfin est étudiée la stabilité des dynamiques non commandées en simple support, sachant que la marche inclut la phase de double support sur-actionnée. Des conditions de stabilité sont déterminées ainsi que le domaine d'attraction pour les dynamiques non commandées en simple support. Il est aussi prouvé tout l'intérêt de la phase sur actionnée pour améliorer la stabilité de la marche.

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