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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

Distribuição de tensões em implantes dentários de diferentes desenhos utilizando fotoelasticidade

Almeida, José Afonso de 28 August 2007 (has links)
Differents drafts of tooth implant insert differents levels of tension in the surrounding bones. This can results in differents prognostics for the implants installed. This work considered by photoelasticity (resilience) of the circuit transmission the gradient of tensions produced in near pre-ordered of the implants when installed in photoelasticity matrix. Eight points were considered when no burden and thirteen points when submited to the axial burden of 0,30N, testing the hypothesis that the tension is the same at the differents implants. The implants used were Titamax TI Medular, Titamax TI Cortical, Titamax Cone Morse and Alvim TI (Neodent, Curitiba, Brazil). The value of the midle cutting tension between the analysed points of each group was submited to the variant analyse showing that has a suggestive statistic difference (p<0,05) between the unburden group. In this situation the Tukey test showed where the difference was. The results outpointed that between the tested implants, the one that produced more medium tension after the installation was the Alvim TI and the axial burden incidence did not result in significative difference at the medium tension produced for all the groups. This work objective was to estimate, in photoelasticity analyse, the tension produced by differents drafts of implants after their installation and after burden incidence, testing the hypothesis that the tension is the same in the differents kinds of implants. / Diferentes desenhos de implantes dentários introduzem diferentes níveis de tensão no osso circundante, podendo resultar diferentes prognósticos para os implantes instalados. Este trabalho avaliou por meio da fotoelasticidade de transmissão circular os gradientes de tensões gerados em pontos prédeterminados próximos aos implantes quando instalados em matrizes fotoelásticas. Foram avaliados oito pontos quando sem carga e 13 pontos quando submetidos ao carregamento axial de 0,30N, testando à hipótese de que a tensão é a mesma nos diferentes tipos de implantes. Foram utilizados os implantes Titamax TI Medular, Titamax TI Cortical, Titamax Cone Morse e Alvim TI (Neodent, Curitiba, Brasil). O valor da tensão cisalhante média entre os pontos analisados de cada grupo foi submetido à análise de variância, demonstrando que houve diferença estatisticamente significante (p<0,05) entre os grupos sem carga. Nessa situação o teste de Tukey demonstrou onde estava a diferença. Os resultados indicaram que entre os implantes testados, o que gerou maior tensão média após a instalação foi o Alvim TI e que a incidência de carga axial não resultou em diferença significativa nas tensões médias geradas para todos os grupos. O objetivo deste trabalho foi avaliar, por meio de análise fotoelástica, a tensão gerada por implantes de diferentes desenhos após sua instalação e após a aplicação de carga, testando à hipótese de que a tensão é a mesma nos diferentes tipos de implantes. / Mestre em Odontologia
2

Commande robuste des robots parallèles à câbles avec mesure extéroceptive / Robust control of cable-driven parallel robots with exteroceptive measurement

Chellal, Ryad 30 September 2016 (has links)
Cette thèse présente un travail complet sur la modélisation, l'identification et la commande des robots parallèles à câbles dans le but d'améliorer les performances dynamiques en termes de rapidité, de précision et de robustesse obtenues, tout en gérant les problèmes liés à l'utilisation de câbles. Dans le cadre de ces recherches, les techniques d'identification et de commande sont améliorées grâce à l'utilisation de mesures extéroceptives, notamment en utilisant la vision. Des méthodes issues des domaines de la robotique et de l'automatique sont mises en oeuvre et comparées. Les validations expérimentales sont effectuées sur un démonstrateur disponible au laboratoire : un robot INCA 6D conçu par la société Haption, équipé d'un système de capture de mouvement Bonita développé par la société Vicon. / This thesis presents a complete work on modelling, identification and control of cable-driven parallel robots in order to improve the dynamic performances in terms of speed, precision and robustness, while managing the problems related to the use of cables. In the context of these researches, the identification and control techniques are improved thanks to the use of exteroceptive sensors, in particular using vision. Methods from the fields of robotics and control are implemented and compared. The experimental validations are performed on a demonstrator available in the laboratory : an INCA 6D robot designed by Haption company, equipped with a Bonita motion capture system developed by Vicon company.

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