Submitted by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2017-01-25T14:25:37Z No. of bitstreams: 1 Dissertação - Leandro T. Nogueira.pdf: 1907447 bytes, checksum: 43e2c4711395f304490584cf48c13045 (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2017-01-25T14:25:52Z (GMT) No. of bitstreams: 1 Dissertação - Leandro T. Nogueira.pdf: 1907447 bytes, checksum: 43e2c4711395f304490584cf48c13045 (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2017-01-25T14:26:11Z (GMT) No. of bitstreams: 1 Dissertação - Leandro T. Nogueira.pdf: 1907447 bytes, checksum: 43e2c4711395f304490584cf48c13045 (MD5) / Made available in DSpace on 2017-01-25T14:26:11Z (GMT). No. of bitstreams: 1 Dissertação - Leandro T. Nogueira.pdf: 1907447 bytes, checksum: 43e2c4711395f304490584cf48c13045 (MD5) Previous issue date: 2016-03-17 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The objective of this study was to address some theorems of geometry and consequently use them to solve exercises. Here are theorems as the Ceva theorem, Menelaus Theorem and Stewart’s theorem, which are very efficient theorems, specially regarding solving exercises that seem complex. That is, knowing these theorems make us very powerful cognitive point of view, of course. We expose here also another magnificent theorem, also known as theorem of Pappus-Guldin. This theorem has as main objective to calculate areas and volumes of surfaces and solids of revolution. Pappos-Guldin theorem is a brilliant theorem. With it can establish several formulas that involve areas and volumes of revolution solids and surfaces, such as the area of ??a circle and the volume of a very trivially cylinder. This theorem enables solving exercises that seem too difficult of a high school student to solve. In this work in very not only care about the dialect, but also with the above content. For example, we leave to those who have the curiosity to see the demonstration of Pappus-Guldin theorem in Appendices A and B, as for the demonstration of it is necessary to use the Differential and Integral Calculus, which until then the high school student remotely have contact. / O objetivo deste trabalho foi abordar alguns teoremas da Geometria e consequentemente usá-los para resolver exercícios. Apresentamos aqui teoremas clássicos como o Teorema de Ceva, o Teorema de Menelaus e o Teorema de Stewart, que são teoremas muito eficientes, principalmente no quesito resolver exercícios que parecem complexos. Isto é, conhecer estes teoremas nos deixam muito poderosos do ponto de vista cognitivo, é claro. Expomos aqui também outro teorema magnífico, conhecido também como Teorema de Pappus- Guldin. Este teorema têm como objetivo principal calcular áreas e volumes de superfícies e sólidos de revolução. O Teorema de Pappus-Guldin é um teorema brilhante. Com ele podemos demonstrar várias fórmulas que envolvem áreas e volumes de superfícies e sólidos de revolução, tais como da área de um círculo e do volume de um cilindro de modo muito trivial. Este teorema possibilita solucionar exercícios que parecem muito difíceis de um aluno do ensino médio resolver. Neste trabalho nos preocupamos muito não só com o dialeto, mas também com o conteúdo exposto. Por exemplo, deixamos, para quem tem a curiosidade ver, a demonstração do Teorema de Pappus-Guldin nos Apêndices A e B, pois para a demonstração do mesmo é necessário o uso do Cálculo Diferencial e Integral, que até então o aluno do ensino médio remotamente tem contato.

Please read the abstract in the section 00front of this document / Dissertation (MEng)--University of Pretoria, 2009. / Mechanical and Aeronautical Engineering / unrestricted

This diploma thesis is dealing with the concepts behind the Stewart platform based flight simulation phenomena along with the method of inverse kinematics computation. Further, a washout algorithm to provide appropriate vestibular sensing to the pilot and ensuring that platform will not reach its limits is presented. Digital filters designed to be used in the implementation of the washout algorithm and their characteristics are also covered. The last part describes the architecture of the whole system and the implementation of individual parts.

No description available.

[pt] Simuladores de movimentos são sistemas mecatrônicos que reproduzem as principais atitudes e movimentos de um veículo. Neste estudo serão analisados simuladores baseados em mecanismos com 3 e 6 graus de liberdade. No segundo caso, o mecanismo é capaz de reproduzir todos os ângulos de atitude (rolagem, arfagem e guinada) e todos os deslocamentos lineares (lateral, vertical e longitudinal) com limitações, porém com amplitude suficiente de modo a possibilitar os principais movimentos associados ao veículo. O uso de transdutores de deslocamento linear nestes mecanismos articulados introduzem elevados efeitos de inércia, além de aumentar a massa dos mesmos, diminuindo sua relação carga/peso e sua eficiência. Atualmente, o grande desenvolvimento de sensores do tipo unidade de medição inercial (IMU) aumentou a disponibilidade destes no mercado e reduziu muito seu custo. Como se trata de acelerômetros triaxiais em conjunto com girômetros também triaxiais, sensores como este podem ser usados para determinar a posição e a orientação no espaço de mecanismos com seis graus de liberdade, como a Plataforma Stewart. Neste trabalho será desenvolvida uma metodologia para modelagem da cinemática de mecanismos paralelos baseada nos derivativos de suas matrizes jacobianas. Esta metodologia é avaliada em um mecanismo paralelo plano de três graus de liberdade e em uma Plataforma Stewart. Com a metodologia de modelagem validada, é implementada uma estratégia de controle baseada no uso de um sensor tipo central inercial para o controle de posição, velocidade e aceleração destes mecanismos. Os resultados das simulações indicam a possibilidade do uso destes sensores nestes tipos de equipamentos e apontam para a necessidade de avaliar esta metodologia em testes experimentais. / [en] Movement simulators are mechatronic systems that reproduce the main attitudes and movements of a vehicle. In this study are examined simulators based on 3 and 6 degrees of freedom mechanisms. In the second case, the mechanism is able to reproduce all the attitude angles (roll, pitch and yaw) and all the linear displacements (sway, heave and surge) with limitations, but with sufficient amplitude to enable the main movements associated with the vehicle. The use of linear displacement transducers in these articulated mechanisms introduce high inertia effects and increase the mass, decreasing the load/weight ratio and efficiency. Currently, the great development of the inertial central type sensors (IMU – Inertial measurement unit) increased the availability of these transducers on market and greatly reduced cost. Since this is a conjunct of triaxial accelerometers with triaxial gyrometers, sensors such as these ones can be used to determine the position and orientation in space of mechanisms with six degrees of freedom, such as the Stewart Platform. In this work it will be developed a methodology for modeling the kinematics of parallel mechanisms based on derivatives of their jacobian matrices. This methodology is evaluated in a planar parallel mechanism of three degrees of freedom and on a Stewart Platform. With the modeling methodology validated, a control strategy based on the use of an inertial unit type sensor for controlling the position, velocity and acceleration of these mechanisms is implemented. The simulations results indicate the possibility of using these sensors in these types of equipment and point to the need to evaluate this methodology in experimental tests.

Este trabalho apresenta o desenvolvimento e as análises de técnicas de controle aplicadas a uma base de movimento de um simulador de vôo. Nos primeiros capítulos são abordados aspectos relacionados com a simulação de movimentos. Uma breve descrição da dinâmica da aeronave e o desenvolvimento do algoritmo de movimento (washout filter) são apresentados. O modelo dinâmico da base de movimento é desenvolvido baseado num manipulador paralelo de seis graus de liberdade chamado de plataforma de Stewart acionado eletricamente. As equações de movimento do atuador eletromecânico são incluídas no modelo dinâmico da plataforma. O controle baseado na dinâmica inversa é uma alternativa para abordar o controle de sistema mecânicos não lineares como a plataforma de Stewart. Porém, essa técnica considera o conhecimento exato do modelo dinâmico do sistema, portanto, a dinâmica não modelada, as incertezas paramétricas e as perturbações externas podem degradar o desempenho do controlador. Além disso, o custo computacional pago pelo cálculo do modelo dinâmico realizado online é muito alto. Nesse contexto, duas estratégias de controle foram aplicadas na malha externa da estrutura de controle baseada na dinâmica inversa para o controle de aceleração na presença de incertezas paramétricas e da dinâmica não modelada, os quais foram introduzidas intencionalmente no processo de aproximar o modelo dinâmico com o objetivo de simplificar a implementação do controle baseado na dinâmica inversa. Na primeira estratégia, o termo robusto de controle foi projetado, provando a estabilidade do sistema linearizado por meio da teoria de estabilidade de Lyapunov. Este controle apresenta o fenômeno conhecido como chattering e então foi adotada uma função de saturação para substituir a lei de controle. Na segunda estratégia, o termo robusto de controle foi projetado considerando um problema de rejeição de distúrbio via controle H \'INFINITO\', onde o controlador considera as incertezas como distúrbios afetando o sistema linearizado resultante da aplicação do controle baseado na dinâmica inversa. Finalmente, três tipos de testes foram realizados para avaliar o sistema de controle: função descritiva, limiar dinâmico e algumas manobras da aeronave calculadas a partir do modelo dinâmico e transformadas através do algoritmo de movimento. As duas estratégias de controle foram comparadas. / This work presents the development and analysis of control techniques applied to a flight simulator motion base. The first chapters deal with subjects related to motion simulation. A brief description of the aircraft dynamic model and the development of the motion algorithm (washout filter) are presented. The motion base dynamics is derived based on a six degree of freedom parallel manipulator driven by electromechanical actuators. The six degree of freedom parallel manipulator is called Stewart platform. The motion equations of the electromechanical actuators are included in the motion base dynamics. Inverse dynamics control is an approach to nonlinear control design, nonetheless, this technique is based on the assumption of exact cancellation of nonlinear terms, therefore, parametric uncertainty, unmodeled dynamics and external disturbances may deteriorate the controller performance. In addition, a high computational burden is paid by computing on-line the complete dynamic model of the motion-base. Robustness can be regained by applying robust control tecniques in the outer loop control structure. In this context, two control strategies were applied in the outer loop of the inverse dynamics control structure linearized system for robust acceleration tracking in the presence of parametric uncertainty and unmodeled dynamic, which are intentionally introduced in the process of approximating the dynamic model in order to simplify the implementation of this approach, the inverse dynamic control. Both control strategies consist of introducing an additional term to the inverse dynamics controller which provides robustness to the control system. In the first strategy, the robust control term was designed proving the stability of the linearized system in the presence of uncertainties, using the Lyapunov stability theory. This control term presents a phenomenon known as chattering. Therefore, a saturation function was adopted to replace the control law. In the second strategy, the robust term was designed for a disturbance rejection problem via H \'INFINITE\' control, where the controller considers the uncertaities as disturbances affecting the linearized system resulting from the application of the inverse dynamic control. Finally, describing function, dynamic threshold and some maneuvers computed from the washout filter were used to evaluate the performance of the controllers. Both approaches were compared.

This thesis provides background information on the Hobby-Eberly Telescope (HET), HET Dark Energy Experiment (HETDEX), Gough-Stewart platforms (GSP), the Prime Focus Instrument Package (PFIP) support structure, and the design methodology used to design said support structure. Each component is analyzed from the point of view of Professor Alex Slocum’s FRDPARRC design methodology. Each aspect of the design is shown to have been derived by following the steps of Slocum’s design method. Material selection, manufacturing techniques, and integration of off-the-shelf components into the support system are also discussed in reference to FRDPARRC. The assembly procedure for the PFIP structure is outlined. Finally, using specific examples from the detailed design, the FRDPARRC method itself is analyzed and its ability to drive innovation in design is evaluated. / text

Cette thèse interroge l’unité de l’économie politique classique en montrant qu’à partir d'une conception de l’autonomie de l’économie, plusieurs articulations de la théorie des prix et d’une «science du législateur» sont possibles. Adam Smith se démarque de François Quesnay et David Ricardo sur ce point. Alors que ces auteurs sont souvent lus à travers le seul prisme de la théorie des prix et donc inclus dans un même projet, nous verrons notamment que Dugald Stewart joua un rôle de premier plan dans le développement d’une lignée qui fût bâtie en excluant Smith. A l’aune des conceptions de l’autonomie de chacun, nous montrons dans une première partie que les concepts de la théorie des prix, notamment la règle de répartition et le processus de circulation, traduisent l’encastrement de l’économie dans une totalité sociale. Or, si Quesnay, Stewart et Ricardo ont chacun pu contribuer à la théorie classique, les analyses de Smith ne respectent pas ses critères de cohérence logique et semblent mener dans l’impasse. Il s’agit en réalité de la marque d’un projet alternatif, mis à jour dans la seconde partie. Quesnay, Stewart et Ricardo présupposent que l’économie est sujette à un ordre qu’il convient de réaliser par la concurrence, mais se distinguent quant aux institutions nécessaires pour ce faire. En revanche, Smith suppose que le législateur n’est pas contraint par des mécanismes économiques. En effet, l’économie n'est pour lui que la modalité d'un lien social général, nécessitant un arbitrage entre rapports sociaux agonistiques. / This thesis aims at questioning the homogeneity of classical political economy by showing that alternative links between price theory and the science of a legislator may be endorsed, depending on what conception of the autonomy of the economic domain is retained. In this respect, Adam Smith departs from François Quesnay and David Ricardo. While these authors are often compared on the sole ground of price theory, and thereby subsumed under a common framework, Dugald Stewart played a prominent role in the development of a trend in the history of ideas which actually excluded Smith from the start. In the light of the author’ understanding of the autonomy of the economy, the first part of this thesis shows that key concepts of classical price theory, among which the rule of distribtuion orthe circulation of commodities, reflect the fact that the economy is embedded in society considered as a whole. Yet, while Quesnay, Stewart and Ricardo did contribute to classical theory in this respect, Smith's analyses do not fit its logical requirements and seem to represent a deadlock.These are however the sign of an alternative project, dealt within the second part of the thesis. Quesnay, Stewart and Ricardo presuppose that the economy is subject to an overall order which ought to be realised thanks to market competition, although they disagree as to what formof institution is best suited to do so. On the contrary, Smith presupposes that the legislator is not impeded by any economic mechanism, since the economy are only a dimension of social interactions, whereby conflicting interests need to be counterbalanced.

Este trabalho apresenta o desenvolvimento e as análises de técnicas de controle aplicadas a uma base de movimento de um simulador de vôo. Nos primeiros capítulos são abordados aspectos relacionados com a simulação de movimentos. Uma breve descrição da dinâmica da aeronave e o desenvolvimento do algoritmo de movimento (washout filter) são apresentados. O modelo dinâmico da base de movimento é desenvolvido baseado num manipulador paralelo de seis graus de liberdade chamado de plataforma de Stewart acionado eletricamente. As equações de movimento do atuador eletromecânico são incluídas no modelo dinâmico da plataforma. O controle baseado na dinâmica inversa é uma alternativa para abordar o controle de sistema mecânicos não lineares como a plataforma de Stewart. Porém, essa técnica considera o conhecimento exato do modelo dinâmico do sistema, portanto, a dinâmica não modelada, as incertezas paramétricas e as perturbações externas podem degradar o desempenho do controlador. Além disso, o custo computacional pago pelo cálculo do modelo dinâmico realizado online é muito alto. Nesse contexto, duas estratégias de controle foram aplicadas na malha externa da estrutura de controle baseada na dinâmica inversa para o controle de aceleração na presença de incertezas paramétricas e da dinâmica não modelada, os quais foram introduzidas intencionalmente no processo de aproximar o modelo dinâmico com o objetivo de simplificar a implementação do controle baseado na dinâmica inversa. Na primeira estratégia, o termo robusto de controle foi projetado, provando a estabilidade do sistema linearizado por meio da teoria de estabilidade de Lyapunov. Este controle apresenta o fenômeno conhecido como chattering e então foi adotada uma função de saturação para substituir a lei de controle. Na segunda estratégia, o termo robusto de controle foi projetado considerando um problema de rejeição de distúrbio via controle H \'INFINITO\', onde o controlador considera as incertezas como distúrbios afetando o sistema linearizado resultante da aplicação do controle baseado na dinâmica inversa. Finalmente, três tipos de testes foram realizados para avaliar o sistema de controle: função descritiva, limiar dinâmico e algumas manobras da aeronave calculadas a partir do modelo dinâmico e transformadas através do algoritmo de movimento. As duas estratégias de controle foram comparadas. / This work presents the development and analysis of control techniques applied to a flight simulator motion base. The first chapters deal with subjects related to motion simulation. A brief description of the aircraft dynamic model and the development of the motion algorithm (washout filter) are presented. The motion base dynamics is derived based on a six degree of freedom parallel manipulator driven by electromechanical actuators. The six degree of freedom parallel manipulator is called Stewart platform. The motion equations of the electromechanical actuators are included in the motion base dynamics. Inverse dynamics control is an approach to nonlinear control design, nonetheless, this technique is based on the assumption of exact cancellation of nonlinear terms, therefore, parametric uncertainty, unmodeled dynamics and external disturbances may deteriorate the controller performance. In addition, a high computational burden is paid by computing on-line the complete dynamic model of the motion-base. Robustness can be regained by applying robust control tecniques in the outer loop control structure. In this context, two control strategies were applied in the outer loop of the inverse dynamics control structure linearized system for robust acceleration tracking in the presence of parametric uncertainty and unmodeled dynamic, which are intentionally introduced in the process of approximating the dynamic model in order to simplify the implementation of this approach, the inverse dynamic control. Both control strategies consist of introducing an additional term to the inverse dynamics controller which provides robustness to the control system. In the first strategy, the robust control term was designed proving the stability of the linearized system in the presence of uncertainties, using the Lyapunov stability theory. This control term presents a phenomenon known as chattering. Therefore, a saturation function was adopted to replace the control law. In the second strategy, the robust term was designed for a disturbance rejection problem via H \'INFINITE\' control, where the controller considers the uncertaities as disturbances affecting the linearized system resulting from the application of the inverse dynamic control. Finally, describing function, dynamic threshold and some maneuvers computed from the washout filter were used to evaluate the performance of the controllers. Both approaches were compared.

Master of Arts / Department of Communication Studies, Theatre, and Dance / Timothy R. Steffensmeier / The 2008 presidential campaign controversy surrounding Rev. Jeremiah Wright’s sermons had the potential to derail Barack Obama’s candidacy. At the heart of the controversy was race, specifically Whiteness. Obama’s speech “A More Perfect Union” is perhaps one of the most significant political speeches addressing race to date, and warrants analysis. However, Barry Brummett’s book Rhetorical Dimensions of Popular Culture (1991) argues the critic should not be limited to discrete traditional texts, rather should be able to break outside such traditional speaker-focused boundaries. Brummett’s mosaic model allows an exploration of the intersection between popular and political rhetoric of Obama and The Daily Show. I will argue from the intersection we see the emergence of the comic frame as a homology that links the disparate texts of Obama and TDS. I will argue the reason the comic frame emerges from the texts is because there is a societal mandate for the comic frame. Thus, I will ultimately argue the mandate for the comic frame can be better understood as a social movement. However, it is a movement comprised of numerous individual movements, and warrants a new term: meta-movement. Obama and TDS are not leaders of this meta-movement, but instead should be seen as contributors. Brummett urges the critic to consider “the political or ideological interests served by ordering a rhetorical transaction in a certain way” (1991, p. 98). I will argue constructing the rhetoric of Obama and TDS with the comic frame serves the ideological interests of those who are fighting for social justice and working to subvert Whiteness. Thus, I have named the meta-movement to which Obama and TDS contribute a critical optimist movement, because the comic frame provides the tools to be critical of hegemony while ultimately reinforcing the optimistic assumption of the comic frame: all humans are ultimately both flawed and good.