Este trabalho trata da modelagem e controle do radiotelescópio de Itapetinga (Atibaia, SP). Ele compreende não só síntese dos modelos e sintonia dos controladores, mas também identificação de sistemas, validação experimental de modelo e controle, reespecificação de componentes, sugestão de nova arquitetura de automação e controle e direcionamento do desenvolvimento que deve ser feito em futuros trabalhos. A parte inicial desta dissertação trata dos principais conceitos envolvidos e do levantamento de informações preliminares para a compreensão do sistema a ser modelado. A seguir é feita a modelagem matemática dos diversos componentes que formam os sistemas de posicionamento dos eixos de elevação e azimute. São então identificados experimentalmente os coeficientes matemáticos dos modelos e são feitas suas validações experimentais. Os controladores PID são sintonizados, baseados na simulação das malhas de controle através das ferramentas matemáticas MATLAB e Simulink. A validação experimental dos controladores é feita e comparada ao sistema de controle atual. São feitos os encaminhamentos das definições de novos motores e amplificadores e desenvolvida uma nova proposta de arquitetura para controle e supervisão do radiotelescópio, dando a ele funcionalidades muito além das que existem atualmente. Finalmente é dado o direcionamento dos próximos passos de desenvolvimento dos modelos, controladores e arquitetura de controle. Com este trabalho procura-se aumentar significativamente o entendimento do sistema de posicionamento do radiotelescópio, criando novos horizontes para o controle, operação, supervisão e manutenção do mesmo. / This work covers the modeling and control of the radio telescope of Itapetinga (Atibaia, SP). It tackles not only model synthesis and controllers tuning, but also system identification, experimental validation of model and control, re-specification of components, as well as a suggestion of a new automation and control architecture, and suggestions for future works. The initial part of this dissertation covers the main concepts and preliminary information for the understanding of the system to be modeled. Then a math model of the several components that form the pointing systems of the elevation and azimuth axis is done, followed by the experimental identification and validation of the math coefficients for the model. PID controllers are tuned based on the simulation of control loops using the math tools MATLAB and Simulink. Then the experimental validation of the controllers is done and compared to the current system control. Preliminary definitions of new motors and amplifiers are suggested, and a new proposal of architecture for radio telescope\'s control and supervision is developed, expanding its functionalities far beyond the ones available today. Finally, directions for the next steps to be taken in order to develop models, controllers and control architecture are given. This work aims to greatly increase the understanding of the radio telescope\'s pointing system, creating new horizons for its control, operation, supervision and maintenance.

The construction and operation of central wastewater treatment plants started around the 20th century. With the advent of rigorous membrane research and development in the middle of the 20th century, more and more wastewater plants started incorporating a Membrane BioReactor, MBR, in their design. The MBR system however is far from perfect. Membrane systems continuously foul, and if fouling is incurred for a long period of time, maintenance and cleaning costs will rise in proportion. A Fouling monitoring and prediction tool has been designed in MATLAB\Simulink. The model takes states related to membrane fouling, and calculates the membrane total resistance based on deterministic and stochastic models. The tool is capable of predicting future TMP cycles based on older TMP performance via an artificial neural network algorithm. TMP data have been synthetically generated from a validated mathematical model. Finally, an artificial neural network controller is implemented to control temperature and MLSS around their desired setpoints. The controller is able to minimize disturbances in both states in a narrow band around their desired setpoints.

In this thesis, we describe a method for controlling the cycle-averaged velocity direction of a fixed-wing aircraft in an unpowered, helical descent. While the aircraft propulsion system is disabled, either intentionally or due to a failure, the aerodynamic control surfaces (aileron, elevator, and rudder) are assumed to be functional. Our approach involves two steps: (i) establishing a stable, steady, helical motion for which the control surfaces are not fully deflected and (ii) modulating the aircraft control surfaces about their nominal positions to ``slant'' the helical flight path in a desired direction relative to the atmosphere, whether to attain a desired impact location, to counter a steady wind, or both. The effectiveness of the control law was evaluated in numerical simulations of a general transport model (GTM). / Master of Science / When an unmanned aircraft is near an authorized airspace (a region of space where the aircraft is not authorized to fly) and experiences a failure such as loss of communication with the control tower,or failure of the GPS or propulsion system, then the aircraft is generally put into an aerodynamic flight termination. In this flight termination method, the aircraft propulsion system is switched off and the control surfaces (aileron, elevator and rudder) are fixed to induce a spin in the aircraft causing it to descend in a helical fashion. However, in the presence of external gusts the aircraft might drift into the unauthorized airspace; or once the aircraft is put into spin, one may want to be able to change the impact location to a safer place. To the best of our knowledge, there exist no control strategies to alter the impact location of the aircraft once it is put into spin and while is continues to spin. In this thesis we describe a method to do so. The aircraft impact location is altered by controlling the cycle-averaged velocity direction of a fixed-wing aircraft in an unpowered, helical descent. While the aircraft propulsion system is disabled, either intentionally or due to a failure, the aerodynamic control surfaces (aileron, elevator, and rudder) are assumed to be functional. Our approach involves two steps: (i) establishing a stable, steady, helical motion for which the control surfaces are not fully deflected and (ii) modulating the aircraft control surfaces about their nominal positions to “slant” the helical flight path in a desired direction relative to the atmosphere, whether to attain a desired impact location, to counter a steady wind, or both. The effectiveness of the control law was evaluated in numerical simulations of a general transport model (GTM).

Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2009. / This thesis details the development of linear control systems that allow a vertical take-off and landing unmanned aerial vehicle to perform transitions between vertical and horizontal flight. Two mathematical models are derived for the control system design. A large non-linear model, describing all the dynamics of the aircraft, is linearised in order to perform optimal control using linear quadratic regulator theory. Another model is decoupled using time scale separation to form separate rigid body and point mass dynamics. The decoupled model is controlled using classical control techniques. Simulation results are used to judge the relative performance of the two control schemes in several fields including: Trajectory tracking, sensitivity to parameters, computational complexity and ease of use.

This report reviews the 2007 financial crisis and the actions of the Federal Reserve. The Full Employment Act of 1946 and the "Humphrey-Hawkins" Act guides the Fed's actions. These two laws outline the long-term goals of the monetary policy framework the Fed uses; however, the framework lacks principles for achieving the mandated long term goals such as reliable, complete data. This report looks at the use of model-based forecasting and gives recommendations for principles which will strengthen the preexisting monetary framework. / text

[pt] O sucesso de diversas tarefas de teleoperacao depende muito da habilidade do operador e de sua capacidade de perceber o ambiente de trabalho. A realimentacao visual em muitos casos nao e suficiente, por exemplo quando a qualidade da imagem do ambiente de trabalho e baixa, quando ocorrem oclusoes na visualizacao, ou quando a tarefa envolve forcas de contato associadas a folgas pequenas visualmente imperceptıveis. Para compensar essas deficiencias, os dispositivos hapticos surgem como uma alternativa a realimentacao visual, ao interagir com o usuario atraves do tato, produzindo uma sensacao de forca. Esta dissertacao apresenta o desenvolvimento e modelagem de um sistema de interface haptica de cinco graus de liberdade para a teleoperacao de robos manipuladores, com foco naqueles que realizam trabalhos em ambientes perigosos ou hostis ao ser humano. A interface e desenvolvida a partir do acoplamento de dois dispositivos hapticos comerciais Novint Falcon, de tres graus de liberdade cada. O sistema resultante do acoplamento e modelado como um manipulador paralelo, capaz de fornecer ao operador, realimentacao de forca 3D (em tres direcoes) e realimentacao de torque em duas direcoes. Para demonstrar a eficiencia do sistema haptico desenvolvido, um ambiente virtual e implementado com o auxılio de tecnicas de computacao grafica e bibliotecas como OpenGL, ODE e Chai3D. Os modelos cinematico e dinamico de um manipulador serial Schilling Titan IV, de seis graus de liberdade, sao implementados no ambiente virtual, incluindo sua interacao com objetos (virtuais) do ambiente de teleoperacao. Controladores nao lineares sao implementados no manipulador serial virtual, incluindo controle de torque computado, robusto, e por modos deslizantes. / [en] The success of many teleoperation tasks depends heavily on the skills of the operator and his ability to perceive the work environment. Visual feedback, in many cases, is not sufficient e.g. when the image quality of the work environment is low, occlusions occur in the display, or when the task involves contact forces associated with visually unnoticeable small clearances. To compensate for these shortcomings, haptic devices emerge as an alternative to visual feedback, in which touch interaction with the user produces force-feedback. This thesis presents the development and modeling of a haptic interface system of five degrees of freedom for the teleoperation of robot manipulators, focusing on those that work in hazardous or hostile environments for humans. The interface is developed from the coupling of two commercial haptic devices Novint Falcon, with three degrees of freedom each. The system resulting from the coupled devices is modeled as a parallel manipulator capable of providing the operator with 3D force feedback (in three dimensions) and torque feedback in two directions. To demonstrate the effectiveness of the developed haptic system, a virtual environment is implemented with the aid of computer graphics techniques and libraries such as OpenGL, ODE and Chai3D. The kinematic and dynamic models of a serial manipulator Schilling Titan IV, with six degrees of freedom, are implemented in the virtual environment, including its interaction with virtual objects for the evaluation of typical teleoperation tasks. Nonlinear controllers are implemented in the virtual serial manipulator, including computed torque and sliding mode control.

Servoposicionadores pneumáticos são sistemas com tecnologia limpa, pois utiliza o ar comprimido como fluido de trabalho, leves, baratos e apresentam boa relação entre a capacidade de carga e a potência fornecida. Contudo, eles apresentam não-linearidades inerentes ao sistema pneumático, como efeitos devidos à compressibilidade do ar, ao atrito e vazamentos. Por estes motivos os controladores lineares mostram-se ineficientes para estes sistemas e é necessário utilizar estratégias de controle mais elaboradas, como, por exemplo, controle por redes neurais, controle com estrutura variável, controle adaptativo ou baseado em linearização por realimentação. Neste trabalho, foi estudada a aplicação do método de linearização por realimentação aliada ao método de controle por realimentação de estados e projeto por alocação de pólos ao controle de um servoposicionador pneumático. A estratégia de linearização por realimentação utiliza as estimativas das não-linearidades do modelo pneumático para linearizar o comportamento do servoposicionador pneumático e permitir o uso tanto de controladores lineares como não-lineares. A análise e prova das características de estabilidade completa do sistema em malha fechada com parâmetros conhecidos foi realizada, obtendo-se a garantia da convergência dos erros de seguimento para zero. Também foi realizada a análise de robustez, com a análise do comportamento do sistema frente às incertezas dos parâmetros estimados. Simulações e ensaios experimentais foram realizados para avaliar o comportamento e a eficiência do controlador proposto. Os resultados do controlador mostram-se promissores, com uma redução de aproximadamente 50% no erro de posição no seguimento de trajetória e na parada precisa com relação às técnicas lineares usualmente aplicadas a estes sistemas. Entretanto, no posicionamento percebe-se a influência do atrito, indicando que a sua compensação deve ser considerada em futuros desenvolvimentos. / Pneumatic positioning systems are clean, lightweight, cheap and present a good rate between the payload and supply power. However, this system shows a highly non-linear behavior, caused mainly by the compression of the air and the friction force. Linear strategies do not present an efficiently control in this kind of system and an improved design technique of control is needed, as neural network control, adaptive control, variable structure control or feedback linearization. In this work, it is developed the application of a feedback linearization control scheme integrated with the state feedback and pole placement method to a pneumatic positioning system. The feedback linearization strategy uses the non-linearities estimation of the pneumatic model to linearize the pneumatic positioning system and allow the use of linear or non-linear controls technique to control the behavior of the servopositioner. In this work, an analysis of the convergence properties of the closed-loop errors of the system when the proposed controller is employed is provided. It is shown that if the parameters are known than the system presents asymptotic convergence of the tracking errors to zero. The robustness properties analysis of the controller is also presented and the system behavior with the uncertainty parameters is analysed. Simulation and experimental tests were performed to assess the behavior and the efficiency of the feedback linearization control. The result of the proposed control shows to be promising on the reduction of position errors in trajectory tracking and in steadystate behavior. The tests show the presence of a strong influence of the friction force and that the friction comparation in techniques must be studied in futher developments.

The technology of UAV (Unmanned Aerial Vehicle) has developed since its conception many years ago. UAVs have several features such as, computerised and autonomous control without the need for an on-board pilot. Therefore, there is no risk of loss of life and they are easier to maintain than manned aircraft. In addition, UAVs have an extended range/endurance capability, sometimes for several days. This makes UAVs attractive for missions that are typically

Thesis (Ph. D.)--Auburn University. / Abstract. Vita. Includes bibliographical references (p. 100-106).

Thesis (Ph. D.)--University of Texas at Austin, 1998. / Vita. Includes bibliographical references (leaves 102-108). Available also in a digital version from Dissertation Abstracts.