Position and vibration control of a flexible beam is studied analytically and in the laboratory. Two different motor types are compared as actuators throughout the thesis: a standard voltage controlled motor and a torque controlled motor. The experimental beam is controlled with a dc-servo motor at its base and is instrumented with strain gages and a potentiometer. The control law is a form of linear, direct-output feedback. State estimators augment the control law to provide rate information that is not available from the instrumentation. Accurate modeling of the system’s inherent damping characteristics is achieved by analyzing experimental data. Gains were iterated yielding minimum-gain norm and minimum-sensitivity norm solutions to meet imposed eigenvalue placement constraints. Results for the two solutions and the two systems are compared and contrasted. Experimental verification of analytical results is hampered by unmodeled system non-linearities. Several attempts at bypassing these obstacles are shown. Finally, conclusions and recommendations are made. / Master of Science / incomplete_metadata

Modern control design is sometimes accompanied by the challenge of dealing with nonlinear systems or plants. In some situations, due to the complexity of the plant and the unavailability of suitable models, the controls engineer opts for developing control schemes based on look-up tables. These tables, typically populated with the steady state inverse input-output characteristics of the plant, are used to compensate the plant via open-loop or closed-loop to solve the control problem. In an effort to present a new alternative, a general theoretical framework for online auto-calibration and control of general nonlinear systems is developed in this dissertation. This technique simultaneously learns the inverse input-state mapping (i.e. the calibration mapping) of the plant while forcing its state to follow a prescribed desired trajectory. The main requirements for the successful application of the novel control law are knowledge of the order of the plant and some generic data to initialize the inverse mapping. This last requirement can be easily fulfilled by using steady-state data or the equilibrium points of the plant. In this approach, the inverse mapping is learned from the current and past states. The learning is accomplished in a composite manner by employing input and state errors. The map is used simultaneously in the feedforward path to control the plant. The performance of the plant subject to this novel controller is validated through simulations and experimental data. The new control method is applied to a novel Electro-Hydraulic Poppet Valve (EHPV). These valves are used in a Wheatstone bridge arrangement for motion control of hydraulic actuators. This is preferred over the conventional use of spool valves due to the energy savings potential. It is shown in this dissertation that this method improves the value of using these types of valves for motion control in hydraulics. This is due to the combination of self-learning (auto-calibration) and better performance for a more efficient operation of hydraulic equipment. Additionally, it is shown that the auto-calibration of the valves can be used for health monitoring of the same, which consequently improves their reliability and expedites maintenance downtime.

Orientador: João Mauricio Rosario / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-07-21T12:17:51Z (GMT). No. of bitstreams: 1 Hermini_HelderAnibal_M.pdf: 23638216 bytes, checksum: 10e5b83880a18ac1bd17625ea99de153 (MD5) Previous issue date: 1996 / Resumo: Este trabalho analisa a nível teórico e de simulação as Não-Linearidades presentes na modelagem e controle de robôs. Ao mesmo tempo é apresentado um estudo detalhado sobre sistemas Não-Lineares envolvendo o desenvolvimento de Controladores Não-Lineares para Manipuladores Industriais. As simulações são realizadas a partir do desenvolvimento do modelo dinâmico de manipuladores de até dois graus de liberdade, considerados rígidos, podendo ser futuramente estendidos a outros graus de liberdade e ao caso de manipuladores flexíveis. A partir dos resultados apresentados na simulação, pode-se mostrar vantagens e inconvenientes da utilização desses controladores em relação aos controladores tradicionais / Abstract: This work analyses the theory and simulation of Non-Linearitys found in the equations and robots control with one and two degrees of freedom. Simultaneously it is presented a detailed work on non linear system involving the development of Non Linear Controls for Industrial Manipulators. This process is moré advantageous than the classical linear controls. Extension to other related works including Flexible Manipulators are also Suggested. / Mestrado / Mecanica dos Sólidos e Projeto Mecanico / Mestre em Engenharia Mecânica

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[pt] Esta dissertação apresenta uma comparação entre técnicas de discretização de controladores, considerando diferentes estruturas de controle. Os tipos de sistemas estudados neste trabalho de pesquisa serão sistemas lineares, invariantes no tempo, determinísticos, causais e monovariáveis. O desempenho das técnicas de discretização serão comparados via figuras de mérito tradicionais, considerando os métodos de discretização, as estruturas dos controladores e os tipos de planta habituais (incluindo problemas benchmarch), sob especificações dadas quanto aos regimes permanente e transiente. / [en] This essay proposes a comparison between techniques of controllers´ discretization considering different controlling structures. The types of systems studied in this research will be linear systems, time-invariant, deterministic, casual and single-variable. The performance of discretization techniques will be compared through figures of traditional aptitude, considering the discretization methods, the controller structures and the kinds of plants (including - benchmarch - problems), under given specifications according to permanent and transitory systems. / [es] Esta disertación presenta una comparación entre técnicas de discretización de controladores, considerando diferentes extructuras de control. Los tipos de sistemas estudiados en este trabajo de investigación son sistemas lineales, invariantes en el tiempo, determinísticos, causales y univariados. Se compara el desempeño de las técnicas de discretización utilizando figuras de mérito tradicionales, considerando los métodos de discretización, las extructuras de los controladores y los tipos de planta habituales (incluyendo problemas - benchmarch - ), bajo especificaciones dadasen relación a los régimenes permanente y transiente.

Les systèmes de communication prennent de nos jours une importance de plus en plus prépondérante dans tous les aspects de la vie courante et les exigences de connectivité se retrouvent dorénavant dans de très nombreux projets. Ces besoins de connexion exigent des débits de communication ainsi que des taux de couverture de plus en plus importants, poussant de ce fait vers l’utilisation de systèmes de communication par satellite (SATCOM). Les applications envisagées n’étant pas limitées à des installations fixes, celles-ci demandent de pouvoir assurer une communication par satellite depuis un porteur en mouvement. Il est donc nécessaire d’utiliser des servomécanismes de positionnement de l’antenne de façon à assurer un pointage correct de l’antenne vers le satellite. Ces positionneurs sont donc asservis de façon à orienter la ligne de visée de l’antenne vers le satellite, avec une erreur angulaire de l’ordre du dixième de degré. Cette précision a pour conséquences certaines exigences fortes sur la conception. Ces contraintes imposent l’utilisation de composants de qualité supérieure, des études mécaniques poussées ainsi que des réglages propres à chaque positionneur après assemblage. Dans le cadre de ces travaux de thèse, une stratégie de pointage différente de l’état de l’art a été conçue. Cette stratégie, nommée Helios (Hybrid Estimator of Line Of Sight), permet de lever certains verrous scientifiques spécifiques. Notamment, elle permet une diminution des performances requises de l’asservissement en position de l’antenne en fournissant une trajectoire plus facile à suivre. Cela permet une diminution des contraintes de conception, notamment mécaniques (frottements, raideurs …). Cela est rendu possible par une meilleure estimation de la direction à pointer, utilisant un plus grand nombre de mesures, sans introduire de retard dans l’estimation. Les moyens d’essais de Thales ont permis d’effectuer des essais expérimentaux sur des prototypes industriels. Ainsi, la stratégie est testée en simulation et en expérimentation sur un hexapode simulant un porteur, permettant un recalage du modèle de simulation à partir de données expérimentales. C’est ainsi que la stratégie est validée en conditions opérationnelles. Afin de réaliser ces tests expérimentaux, une étape de mise en place du moyen d’essais a été réalisée. Notamment, les outils de communication ont été mis au point (bus de terrains, liaisons série …). L’asservissement en position de la station a été réalisé à partir d’une identification non-paramétrique en boucle fermée du mécanisme. L’intégration de la station complète a été réalisée, permettant ainsi les tests en extérieur, sur un hexapode. / In military and civil application, satellite communications (SACTOM) are often needed on moving vehicles (drones, planes, land vehicles, vessels…) in order to transfer all kind of data (pictures, videos, internet …). These types of stations are called SATCOM On The Move (SOTM). In order insure high data rates, the antenna must be directional, which means that they direct electro-magnetic waves in a particular direction of space, called line of sight. The line of sight must be steered in order to be aligned with the satellite to insure a strong communication link with the highest data rate possible. Stabilized platforms, called Antenna Positioning System, aim to steer the antenna’s line of sight in the satellite direction. The pointing requirements are the source of conception constraints that reduce the cost efficiency of the overall station. This PhD report focus on the development and the study of a new pointing strategy called Helios (“Hybrid Estimator of LIne Of Sight”). This algorithm uses least squares to found the antenna pattern in real time, using an observation window. Among others, it allows to reduce the bandwidth of the control loops by generating a trajectory easier to follow. Therefore, it decreases the conception constraints (friction, backlash, field bus data rate …). Helios is tested through experimentation, using Thales industrial prototypes. The vehicle is emulated by a hexapod. Simulation is carried out in order to fit the measured experimental behavior. To do so, parametrical and non-parametrical identification has been done on the SOTM prototype. This way, Helios is validated and studied in operational conditions.