Submitted by Andressa Lima (andressa@uepb.edu.br) on 2016-08-10T17:44:54Z No. of bitstreams: 1 PDF - Luiz Gustavo de Sá Bezerra.pdf: 4326507 bytes, checksum: 7e18992908f0a7c6649fbb3092bdb145 (MD5) / Approved for entry into archive by Luciana Medeiros (luciana@uepb.edu.br) on 2016-08-17T17:24:31Z (GMT) No. of bitstreams: 1 PDF - Luiz Gustavo de Sá Bezerra.pdf: 4326507 bytes, checksum: 7e18992908f0a7c6649fbb3092bdb145 (MD5) / Made available in DSpace on 2016-08-17T17:24:31Z (GMT). No. of bitstreams: 1 PDF - Luiz Gustavo de Sá Bezerra.pdf: 4326507 bytes, checksum: 7e18992908f0a7c6649fbb3092bdb145 (MD5) Previous issue date: 2016-04-08 / Não / The comparative mythologist Joseph Campbell found that the myths basically comprise the same story, retold, last forever, in myriad variations. In the book, The Hero with a Thousand Faces (CAMPBELL, 2007), are compiled their most recurrent convictions about the oral tradition and the written literature, reaching a common denominator: the monomyth. This concept can be understood in terms of the Hero's Journey, revealing cyclical narratives that can be used both in understanding human problems and as a guiding creative writing. Not coincidentally, they are also the backbone that supports the work of this subject: the comics, All-Star Superman (MORRISON, QUITELY; 2012). The story on screen is divided into twelve independent chapters that, when read in its entirety, allows a series of allusions to Hero's Journey and the remitologizações manifestation of the classic / traditional mythical hero. Indeed, the overall goal is to see how the three acts Campbell Monomyth - called evidence and return - are hidden in the text and illustrations of the comic of All-Star Superman. Through literature, the work is organized into three chapters and crosses, an ancillary way, the study Meletínski (2002) on literary archetypes; the buildings listed in the essay The Myth of Superman, Eco (2015); and liquid modernity concepts, worked by Bauman (2001), and the notion of mitopoeta by Ribeiro (2013). It is observed that Superman stands as a modern / contemporary hero and differs from classic / traditional mythical hero; the first of which is presented as a man whose acts of heroism are highlighted by the facts of contemporary, dynamism and unpredictability typical of Romanesque productions; already the second, is stuck in the middle of a temporal vortex that stabilizes and immobilizes it forward to new possibilities. So while the mythical hero "is" the modern hero lives in the midst of a "maybe." On the other hand, we arrive at the insight that in the comics, symbolic objects - like Superman costume - are not reserved solely the narrative, but end up amplifying the emotional reader demonstration outside the materialization of images and imagination. Furthermore, it is identified that the notion of cultural producer - illustrator writer or artist - in comic books fits the classification Ribeiro (2013) gives the mitopoeta. As regards the proposal of reading All-Star Superman, it appears that Campbell's Monomyth is not fully followed to the letter, the synchronic sense capitulate story, showing that the Hero's Journey structure need not necessarily be established so precisely . Finally, it is concluded that this comic is established within the standard monomyth as a form, but not as a formula, allowing sections and subsections are deleted, added and even shuffled without cool the hero myth / O mitólogo comparativo, Joseph Campbell, descobriu que os mitos basicamente compõem a mesma história, recontada, ad eternum, em inumeráveis variações. Na obra, O Herói de Mil Faces (CAMPBELL, 2007), são compiladas suas convicções mais recorrentes sobre a tradição oral e a literatura escrita, chegando a um denominador comum: o monomito. Esse conceito pode ser compreendido nos termos da Jornada do Herói, revelando narrativas cíclicas, que podem ser empregadas tanto na compreensão de problemas humanos quanto como norteadoras da escrita criativa. Não por acaso, são também o sustentáculo que ampara o objeto de estudo do presente trabalho: a história em quadrinhos, Grandes Astros Superman (MORRISON; QUITELY, 2012). A estória em tela está estruturada em doze capítulos independentes que, quando lidos na íntegra, permite-se uma série de alusões a Jornada do Herói, bem como a manifestação de remitologizações do herói mítico clássico/tradicional. Com efeito, o objetivo geral é verificar de que maneira os três atos do monomito de Campbell - chamado, provas e retorno - estão ocultos no texto e ilustrações da história em quadrinhos de Grandes Astros Superman. Por meio de pesquisa bibliográfica, o trabalho está organizado em três capítulos e perpassa, de forma acessória, o estudo de Meletínski (2002) sobre arquétipos literários; as construções elencadas no ensaio O Mito do Superman, de Eco (2015); e os conceitos de modernidade líquida, trabalhado por Bauman (2001), e a noção de mitopoeta por Ribeiro (2013). Observa-se que o Superman se posta como herói moderno/contemporâneo e se diferencia do herói mítico clássico/tradicional; sendo que o primeiro se apresenta como um sujeito cujos atos de heroísmo são ressaltados pelos fatos da contemporaneidade, o dinamismo e a imprevisibilidade típica de produções romanescas; já o segundo, está preso a um vórtice temporal que estabiliza ou imobiliza-o frente a novas possibilidades. Assim, enquanto o herói mítico “é”, o herói moderno vive em meio a um “pode ser”. Por outro lado, chega-se ao discernimento de que nas histórias em quadrinhos, objetos simbólicos – como o traje do Superman – não são reservados tão somente a narrativa, mas acabam amplificando a manifestação emocional do leitor diante da materialização de imagens e imaginário. Outrossim, identifica-se que a noção de produtor cultural – roteirista ou artista ilustrador – nas histórias em quadrinhos se enquadra na classificação que Ribeiro (2013) confere ao mitopoeta. No que toca a proposta de leitura de Grandes Astros Superman, constata-se que o monomito de Campbell não é totalmente seguido à risca, no sentido sincrônico capitular da estória, evidenciando que a estrutura da Jornada do Herói não precisa necessariamente se apresentar com tanta precisão. Por fim, conclui-se que essa história em quadrinhos se estabelece dentro do padrão do monomito enquanto forma, mas não como fórmula, permitindo que seções e subseções sejam excluídas, acrescentadas e até embaralhadas, sem arrefecer o mito do herói.

The term proximity operations has been widely used in recent years to describe a wide range of space missions that require a spacecraft to remain close to another space object. Such missions include, for example, the inspection, health monitoring, surveillance, servicing, and refueling of a space asset by another spacecraft. One of the biggest challenges in autonomous space proximity operations, either cooperative or uncooperative, is the need to autonomously and accurately track time-varying relative position and attitude references, i.e., pose references, with respect to a moving target, in order to avoid on-orbit collisions and achieve the overall mission goals. In addition, if the target spacecraft is uncooperative, the Guidance, Navigation, and Control (GNC) system of the chaser spacecraft must not rely on any help from the target spacecraft. In this case, vision-based sensors, such as cameras, are typically used to measure the relative pose between the spacecraft. Although vision-based sensors have several attractive properties, they introduce new challenges, such as no direct linear and angular velocity measurements, slow update rates, and high measurement noise. This dissertation investigates the problem of autonomously controlling and estimating the pose of a chaser spacecraft with respect to a moving target spacecraft, possibly uncooperative. Since this problem is inherently hard, the standard approach in the literature is to split the attitude-tracking problem from the position-tracking problem. Whereas the attitude-tracking problem is relatively simple, since the rotational motion is independent from the translational motion, the position-tracking problem is more complicated, as the translational motion depends on the rotational motion. Hence, whereas strong theoretical results exist for the attitude problem, the position problem typically requires additional assumptions. An alternative, more general approach to the pose control and estimation problems is to consider the fully coupled 6-DOF motion. However, fewer results exist that directly address this higher dimensional problem. The main contribution of this dissertation is to show that dual quaternions can be used to extend the theoretical results that exist for the attitude motion into analogous results for the combined position and attitude motion. Moreover, this dissertation shows that this can be accomplished by (almost) just replacing quaternions by dual quaternions in the original derivations. This is because dual quaternions are built on and are an extension of classical quaternions. Dual quaternions provide a compact representation of the pose of a frame with respect to another frame. Using this approach, three new results are presented in this dissertation. First, a pose-tracking controller that does not require relative linear and angular velocity measurements is derived with vision-based sensors in mind. Compared to existing literature, the proposed velocity-free pose-tracking controller guarantees that the pose of the chaser spacecraft will converge to the desired pose independently of the initial state, even if the reference motion is not sufficiently exciting. In addition, the convergence region does not depend on the gains of the controller. Second, a Dual Quaternion Multiplicative Extended Kalman Filter (DQ-MEKF) is developed from the highly successful Quaternion MEKF (Q-MEKF) as an alternative way to achieve pose-tracking without velocity measurements. Existing dual quaternion EKFs are additive, not multiplicative, and have two additional states. The DQ-MEKF is experimentally validated and compared with two conventional EKFs on the 5-DOF platform of the Autonomous Spacecraft Testing of Robotic Operations in Space (ASTROS) facility at the School of Aerospace Engineering at Georgia Tech. Finally, the velocity-free pose-tracking controller is compared qualitatively and quantitatively to a pose-tracking controller that uses the velocity estimates produced by the DQ-MEKF through a realistic proximity operations simulation. Third, a pose-tracking controller that does not require the mass and inertia matrix of the chaser satellite is suggested. This inertia-free controller takes into account the gravitational acceleration, the gravity-gradient torque, the perturbing acceleration due to Earth's oblateness, and constant -- but otherwise unknown -- disturbance forces and torques. Sufficient conditions on the reference pose are also given that guarantee the identification of the mass and inertia matrix of the satellite. Compared to the existing literature, this controller has only as many states as unknown elements and it does not require a priori known upper bounds on any states or parameters. Finally, the inertia-free pose-tracking controller and the DQ-MEKF are tested on a high-fidelity simulation of the 5-DOF platform of the ASTROS facility and also experimentally validated on the actual platform. The equations of motion of the 5-DOF platform, on which the high-fidelity simulation is based, are derived for three distinct cases: a 3-DOF case, a 5-DOF case, and a (2+1)-DOF case. Four real-time experiments were run on the platform. In the first, a sinusoidal reference attitude with respect to the inertial frame is tracked using VSCMGs. In the second, a constant reference attitude is maintained with respect to a target object using VSCMGs and measurements from a camera. In the third, the same sinusoidal reference attitude with respect to the inertial frame tracked in the first experiment is now tracked using cold-gas thrusters. Finally, in the fourth and last experiment, a time-varying 5-DOF reference pose with respect to the inertial frame is tracked using cold-gas thrusters.