Thesis. 1976. M.S.--Massachusetts Institute of Technology. Dept. of Aeronautics and Astronautics. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND AERONAUTICS. / Includes bibliographical references. / by David M. Stofko. / M.S.

Thesis (M.S.)--California Polytechnic State University, 2009. / Title from PDF title page; viewed on June 11, 2009. "May 2009." "In partial fulfillment of the requirements for the degree [of] Master of Science in Aerospace Engineering." "Presented to the faculty of California Polytechnic State University, San Luis Obispo." Major professor: Daniel Biezad, Ph.D. Includes bibliographical references (p. 78-79). Also available on microfiche.

With the agricultural mechanization in expansion in the country, a lot of farmers, in order to optimize resources in the property, invest in technologies and agriculture techniques of precision for decreasing the cost of production, turning this activity into something feasible to their businesses. The objective of the present study was to run a comparative analysis between two direction systems, one of them without precision orientation, guided by the operator and the other system using resources of an automatic pilot, in order to limit through field tests the overlapping in the application of chemicals generated during the traffic of the group tractor plus sprayer. The spraying tests were run in a rectangular field of 20 hectares, all the circuit of movement of the group tractor plus sprayer followed the operation process back and forth with maneuvers on the heads of the field with previous alignment in each line of application. To be possible to obtain the medium overlapping of the width of the sprayer bar of 18 meters on both systems of direction, about 192 points average were collected throughout each strip, reaching the value of overlapping to the system without precision orientation of 9.48% and 0.44% for the automatic pilot system. From these data, the number of necessary transversal lines was presented for each of the systems of direction to attend to the experimental area, making it possible to estimate the total expenses and the cost reduction per hectare. Saving 17.61 R$ per hectare, it is possible to say that the investment of R$ 64,145.43 (sixty-four thousand, one hundred and forty-five reais and forty-three cents), referring to the acquisition of the system of automatic pilot, it is feasible for the studied property of 1300 hectares, for a period of amortization of 10 years referring to the life span of equipment involved (tractor and sprayer). / Com a mecanização agrícola em expansão no pais, muitos produtores rurais, afim de otimizar recursos na propriedade, investem em tecnologias e técnicas de agricultura de precisão para uma diminuição do custo de produção, tornando esta atividade economicamente viável para os seus negócios. O objetivo do presente trabalho foi realizar uma análise comparativa, entre dois sistemas de direcionamento, um sem orientação de precisão, guiado pelo operador e o outro sistema utilizando recursos de um piloto automático, afim de delimitar por meio de testes de campo a sobreposição na aplicação de agrotóxico gerado durante o trafego do conjunto trator mais pulverizador. Os testes de pulverização foram realizados em um campo retangular de 20ha, todo circuito de deslocamento do conjunto trator mais pulverizador seguiu o processo de operação vai e vem com manobras nas cabeceiras do talhão com alinhamento prévio antes de cada linha de aplicação. Para que fosse possível obter a sobreposição média da largura da barra do pulverizador de 18m de ambos os sistemas de direcionamento, foram coletados em média 192 pontos de medidas ao longo de cada faixa, chegando ao valor de sobreposição para o sistema sem orientação de precisão de 9,48% e de 0,44% para o sistema de piloto automático. A partir destes dados, foi apresentado o número de linhas transversais necessárias para cada um dos sistemas de direcionamento para atender a área experimental, tendo assim como estimar os gastos totais e a redução de custos por hectare. Com a economia de R$/ha 17,61, é possível afirmar que o investimento de R$ 64.145,43 (Sessenta e quatro mil cento e quarenta e cinco reais com quarenta e três centavos), referente a aquisição do sistema de piloto automático, é viável para a propriedade estudada de 1300 hectares, para um período de amortização de 10 anos referente à vida útil dos equipamentos envolvidos (trator e pulverizador).

When the target of a reaching movement is displaced suddenly, people update their movement to take account of the jump, correcting their trajectory online to end the movement at the new target location. These corrections are initiated too rapidly to be conscious, and occur when they are uninstructed (Pisella et al., 2000) or the participant is unaware of the change in location (Goodale et al., 1986). These findings have been taken as evidence that fast corrections occur automatically, and the spatial updating of reach trajectories has become known as the ‘automatic pilot’ (Pisella et al., 2000). This thesis set out to investigate the cognitive, attentional and neurological aspects of the automatic pilot, in three series of related experiments, all employing a double-step reaching task. Experiments 1 - 4 investigated how strongly automatic reach corrections are, by manipulating the influence of conscious intention and cognitive load. These experiments confirmed that the automatic pilot is at most weakly automatic, as correction efficiency is enhanced by an explicit instruction to follow target jumps and, conversely, corrections can be overridden by an intention to resist them. However, voluntary inhibition of the automatic pilot can be disrupted by placing participants under heavy cognitive load, whilst voluntary enhancement is unaffected by this manipulation. Thus, voluntary suppression of the automatic pilot is effortful, but enhancement towards greater responsiveness is seemingly effortless. Experiments 5 - 8 explored the properties of the visual target displacement that drive the automatic pilot response in a double-step reaching task. These experiments demonstrate that correction efficiency is lawfully related to jump salience, but that the onset of the new target location drives correction responses more powerfully than the offset of the original target. However, the maximal correction rates obtained from a simultaneous onset and offset, were too great to be attributed simply to the additive influences of onsets and offsets. The onset and offset components of the target jump are thus synergistic. It is suggested that this reflects the contribution of an apparent motion signal induced by simultaneous onset and offsets, which strongly drives the automatic pilot system. Experiment 9 examined an asymmetry in correction efficiency, favouring rightward over leftward target jumps, evident throughout the earlier experiments. Correction efficiency was assessed for right- and left-handed participants responding to rightward and leftward target jumps. The pattern of results indicated that each hand is advantaged for responding to ipsilaterallydirected jumps, which may reflect biomechanical or hemispheric compatibility effects. However, there was also an overall differential advantage for rightward jumps, which was independent of handedness, or hand used. This suggests a left-hemispheric advantage for automatic correction behaviour, independent of handedness. Finally, Experiments 10 - 14 considered whether the automatic pilot deficit in optic ataxia is simply a manifestation of the more general misreaching deficit. Across several different target conditions, the pattern of online correction in optic ataxia refuted a simple misreaching explanation, suggesting that it is a specific functional consequence of dorsal stream damage.

Les énergies renouvelables représentent aujourd'hui un domaine de développement de plus en plus important, au vu de la consommation énergétique mondiale et de ses conséquences désastreuses sur l'environnement. Les différents accords politiques, notamment l'accord de Paris, ne peuvent à eux seuls apporter une solution définitive au changement climatique actuel. Les contraintes imposées par la réduction des émissions de CO_2 et l’augmentation du prix du pétrole dans l’industrie maritime ont poussé Yves Parlier à lancer le projet « beyond the sea » dans le but de développer des cerfs-volants (kites) dédiés à la propulsion auxiliaire des navires. L'objectif principal de cette étude est donc la modélisation et la commande robuste d'une aile de kite en vol dynamique. Le but à terme étant l'élaboration d'un pilote automatique dédié à la traction d'un navire par kite. Un modèle « point-masse » du kite est proposé afin de comprendre et contrôler sa dynamique. Les différents paramètres du modèle sont estimés à partir de données expérimentales obtenues lors d’essais en conditions réelles. Des simulations en boucle ouverte sont proposées afin de valider la cohérence du modèle. Pour effectuer un vol dynamique, une trajectoire en forme de huit est définie dans la fenêtre de vol. La position, la taille et l’orientation de cette trajectoire sont des paramètres ajustables par l’utilisateur. Un algorithme de suivi de trajectoire est développé permettant ensuite de synthétiser une loi de commande robuste intégrant le modèle du kite. Ce pilote automatique permet donc d’effectuer une grande variété de trajectoires pour toute une gamme de vitesses de vent. Enfin, des simulations en boucle fermée montrant les performances théoriques du système mettent en évidence l’intérêt de la propulsion auxiliaire des navires par kite. / The need in reducing the CO_2 emissions and the increase of oil prices affect all transportation industries and especially the maritime industry. This has led to the search for more energy-saving ship propulsion systems. Taking advantage of wind energy by using tethered wings, or kites, as an alternative propulsion source can be an effective solution. The "beyond the sea" project, led by Yves Parlier, aims to provide ships an alternative green energy source. In most wind conditions, compared to a static flight, a dynamic motion of a tethered wing with an eight-shaped pattern can provide sufficient force through traction to tow a ship. Therefore, the main objective of this study is the modeling and robust control of a tethered kite in dynamic flight. To this end, a point mass model is first used to describe the kite dynamics. The model parameters are estimated from experimental data and the aerodynamic coefficients are identified using data from a quasi-static flight. Open loop simulations are conducted to verify the kite behavior and the overall coherence of the model. To ensure a dynamic flight, an eight-shaped trajectory is defined within the wind window. Its position, size, orientation and direction are all adjustable parameters. A path-following strategy is then developed in order to design a robust control law including the kite model. This allows the system to be used in different trajectories with a wide range of wind speeds. Closed-loop simulations are presented to show the efficiency of the path-following algorithm, and the various theoretical performances obtained shows the efficiency of a kite dedicated to vessels auxiliary propulsion.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science; and, (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING / Includes bibliographical references. / by Marc Bodson. / M.S.

In this work we investigate the use of state-of-the-art tools for the regulation of complex, non-linear systems to improve the methodologies currently applied to trim comprehensive virtual prototypes of rotors and rotorcrafts. Among the several methods that have been proposed in the literature, the auto-pilot approach has the potential to solve trim problems efficiently even for the large and complex vehicle models of modern comprehensive finite element-based analysis codes. In this approach, the trim condition is obtained by adjusting the controls so as to virtually ``fly' the system to the final steady (periodic) flight condition. Published proportional auto-pilots show to work well in many practical instances. However, they cannot guarantee good performance and stability in all flight conditions of interest. Limit-cycle oscillations in control time histories are often observed in practice because of the non-linear nature of the problem and the difficulties in enforcing the constant-in-time condition for the controls. To address all the above areas of concern, in this research we propose a new auto-pilot, based on non-linear model-predictive control (NMPC). The formulation uses a non-linear reference model of the system augmented with an adaptive neural element, which identifies and corrects the mismatch between reduced model and controlled system. The methodology is tested on the wind-tunnel trim of a rotor multibody model and compared to an existing implementation of a classic auto-pilot. The proposed controller shows good performance without the need of a potentially very expensive tuning phase, which is required in classical auto-pilots. Moreover, model-predictive control provides a framework for guaranteeing stability of the non-linear closed-loop system, so it seems to be a viable approach for trimming complete rotorcraft comprehensive models in free-flight.

The conventional Mini and Large scale Unmanned Aerial Vehicle systems span anywhere from approximately 12 inches to 12 feet; endowing them with larger propulsion systems, batteries/fuel-tanks, which in turn provide ample power reserves for long-endurance flights, powerful actuators, on-board avionics, wireless telemetry etc. The limitations thus imposed become apparent when shifting to Micro Aerial Vehicles (MAVs) and trying to equip them with equal or near-equal flight endurance, processing, sensing and communication capabilities, as their larger scale cousins. The conventional MAV as outlined by The Defense Advanced Research Projects Agency (DARPA) is a vehicle that can have a maximum dimension of 6 inches and weighs no more than 100 grams. Under these tight constraints, the footprint, weight and power reserves available to on-board avionics and actuators is drastically reduced; the flight time and payload capability of MAVs take a massive plummet in keeping with these stringent size constraints. However, the demand for micro flying robots is increasing rapidly. The applications that have emerged over the years for MAVs include search&rescue operations for trapped victims in natural disaster succumbed urban areas; search&reconnaissance in biological, radiation, natural disaster/hazard succumbed/prone areas; patrolling&securing home/office/building premises/urban areas. VTOL capable rotary and fixed wing flying vehicles do not scale down to micro sized levels, owing to the severe loss in aerodynamic efficiency associated with low Reynolds number physics on conventional airfoils; whereas, present state of the art in flapping wing designs lack in one or more of the minimum qualities required from an MAV: Appreciable flight time, appreciable payload capacity for on-board sensors/telemetry and 6DoF hovering/VTOL performance. This PhD. work is directed towards overcoming these limitations. Firstly, this PhD thesis presents the advent of a novel Quad-Wing MAV configuration (called the QV). The Four-Wing configuration is capable of performing all 6DoF flight maneuvers including VTOL. The thesis presents the design, conception, simulation study and finally hardware design/development of the MAV. Secondly, this PhD thesis proves and demonstrates significant improvement in on-board Energy-Harvesting resulting in increased flight times and payload capacities of the order of even 200%-400% and more. Thirdly, this PhD thesis defines a new actuation principle called, Fixed Frequency, Variable Amplitude (FiFVA). It is demonstrated that by the use of passive elastic members on wing joints, a further significant increase in energy efficiency and consequently reduction in input power requirements is observed. An actuation efficiency increase of over 100% in many cases is possible. The natural evolution of actuation development led to invention of two novel actuation systems to illustrate the FiFVA actuation principle and consequently show energy savings and flapping efficiency improvement. Lastly, but not in the least, the PhD thesis presents supplementary work in the design, development of two novel Micro Architecture and Control (MARC) avionics platforms (autopilots) for the application of demonstrating flight control and communication capability on-board the Four-Wing Flapping prototype. The design of a novel passive feathering mechanism aimed to improve lift/thrust performance of flapping motion is also presented.

Submitted by JÚLIO HEBER SILVA (julioheber@yahoo.com.br) on 2017-03-21T18:01:54Z No. of bitstreams: 2 Dissertação - Rubens Antônio Alves - 2015.pdf: 7966348 bytes, checksum: 5a95a9ee436c444d586451331b40e5a0 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2017-03-22T12:33:33Z (GMT) No. of bitstreams: 2 Dissertação - Rubens Antônio Alves - 2015.pdf: 7966348 bytes, checksum: 5a95a9ee436c444d586451331b40e5a0 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-03-22T12:33:33Z (GMT). No. of bitstreams: 2 Dissertação - Rubens Antônio Alves - 2015.pdf: 7966348 bytes, checksum: 5a95a9ee436c444d586451331b40e5a0 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2015-09-30 / Outro / This Project, in the electrical engineering area, consists in the development of a complete control system, hardware and software, for controlling model airplanes of the fixedwing and rotary-wing types, aiming the implementation of an automatic control system compatible with the necessity of autonomous and aided flights, applied to critical systems monitoring.The final system consists of a controller, or automatic pilot, with specific hardware and software, capable of controlling a model airplane using GPS coordinates, in a way that allows the airplane to go through a planned route and go back to the starting point in an autonomous way. The controller should receive, in ground, the programmed route; the model should answer to the pilot commands, within a visual range when operating in the aided mode, and should go through the programmed route in the autonomous mode, after confirmation of the pilot. After reaching the end of the programmed route, the model airplane should return to the starting point, keeping the maximum flight level of the route as the reference height. The model airplane will carry in a communication system to allow the monitoring process from a ground station, able to keep updated the airworthy conditions, as well as the level of accuracy between the actual and the planned route. The communication may be carried out directly using a radio link, with the receiver allocated in a mobile ground station, monitored by a pilot, to make higher the security level. However, the model airplane may transfer the data through a GPRS link, connected to the web system, which transfers the data to the ground station. In this case, the ground station must be connected to the web.The route saved in the model control system is built based on online maps directly linked by the software for the mission programming and monitoring, which can carry out the treatment and storage of the model data and parameters. The programming of the stability control and route, with primary data of latitude, longitude and height allows the real time monitoring of the model, related to the planned route and throught images captured by embedded video cameras. All data are storage following a timeline process, such that they can be recovered for futher analysis. / Esta disertação da área de engenharia elétrica consiste na construção de um sistema de controle completo de hardware e software para controle de um aeromodelo de asa fixa e/ou asa móvel, de maneira a implementar um piloto automático compatível com as necessidades de voo autônomo ou assistido, sendo que tal sistema deverá ser compatível com a precisão de voo aplicada a monitoramento de sistemas críticos.O sistema é constituído por uma placa controladora composta por hardware e firmware específicos, capaz de controlar um modelo orientado por coordenadas GPS, para que o mesmo percorra uma rota predeterminada e retorne ao ponto de partida de forma autônoma. A placa recebe, ainda em solo, a programação da rota a ser percorrida; o aeromodelo deve responder normalmente aos comandos do controle remoto do piloto em solo, respeitando o raio de alcance visual do piloto no modo assistido e segue a rota programada no modo autônomo após confirmação de comando do piloto. No final do percurso o aermodelo volta em trajetória reta para o ponto de partida, respeitando a maior altura do trajeto. O aeromodelo deve ser munido de sistema de comunicação para o devido acompanhamento em solo das condições de aeronavegabilidade do aeromodelo em voo, bem como a verificação dos níveis de precisão em relação à rota programada. A comunicação pode ser feita diretamente por sistema de link de rádio, direcionada a um terminal móvel em solo, que é acompanhado pelo piloto, para aumentar o nível de segurança, mas o aeromodelo também pode comunicar por rede de celular GPRS, conectado à internet, que direciona os dados ao terminal em solo. Nesse caso, o terminal, também deverá estar conectado à internet. A rota programada no aeromodelo é construída com base em mapas online conectados diretamente ao software de programação e acompanhamento de missão, que faz o tratamento e armazenamento dos dados e parâmetros do aermodelo. Tanto a programação de controle de estabilidade, quanto de rota, com dados primários relativos a latitude, longitude e altura, permitem o acompanhamento em tempo real do aeromodelo junto à rota programada e também através da imagem da câmera de gravação embarcada no aeromodelo. Todos os dados são gravados com base em processo de linha do tempo, que podem ser recuperados em conjunto para análise posterior.