<p>Modern information technology increases the use of computers in training systems as well as in command-and-control systems in military services and public-safety organizations. This computerization combined with new threats present a challenging complexity. Situational awareness in evolving distributed operations and follow-up in training systems depends on humans in the field reporting observations of events. The use of this observer-reported information can be largely improved by implementation of models supporting both reporting and computer representation of objects and phenomena in operations.</p><p>This thesis characterises and describes observer model-based data collection in distributed tactical operations, where multiple, dispersed units work to achieve common goals. Reconstruction and exploration of multimedia representations of operations is becoming an established means for supporting taskforce training. We explore how modelling of operational processes and entities can support observer data collection and increase information content in mission histories. We use realistic exercises for testing developed models, methods and tools for observer data collection and transfer results to live operations.</p><p>The main contribution of this thesis is the systematic description of the model-based approach to using observers for data collection. Methodological aspects in using humans to collect data to be used in information systems, and also modelling aspects for phenomena occurring in emergency response and communication areas contribute to the body of research. We describe a general methodology for using human observers to collect adequate data for use in information systems. In addition, we describe methods and tools to collect data on the chain of medical attendance in emergency response exercises, and on command-and-control processes in several domains.</p>

The choice of technology for automotive actuators is driven by the need of high power to size ratio. In general, electro-pneumatic actuators are preferred for application around the engine as they are compact, powerful and require simple controlling devices. Specially, Variable Geometry Turbochargers (VGTs) are almost always controlled with electro-pneumatic actuators. This is a challenging application because the VGT is an important part of the engine air path and the latter is responsible for intake and exhaust air quality and exhaust emissions control. With government regulations on vehicle pollutant emissions getting stringent by the year, VGT control requirements have also increased. These regulations and requirements can only be fulfilled with precise dynamic control of the VGT through its actuator. The demands on actuator control include robustness against uncertainty in operating conditions, fast and smooth positioning without vibration, limited number of measurements. Added constraints such as nonlinear dynamic behavior of the actuator, friction and varying aerodynamic forces in the VGT render classical control methods ineffective. These are the main problems that form the core of this thesis.In this work, we have addressed the above mentioned problems, using model based control complemented with robust control methods to overcome operational uncertainties and parametric variations. In the first step, a detailed physical model of an electro-pneumatic actuator has been developed; taking into account the nonlinear characteristics originating from air compressibility and friction. Means to compensate for aerodynamic force have been studied and implemented in the next step. These include model parametric adaptation and one dimensional CFD (Computational Fluid Dynamics) modeling. The complete model has been experimentally validated and a sensitivity analysis has been conducted to identify the parameters which have the greatest impact upon the actuator's behavior. The detailed simulation model has then been simplified to make it suitable for control purposes while keeping its essential behavioral characteristics (i.e. transients and dynamics). Next, robust controllers have been developed around the model for the control objective of accurate actuator positioning in presence of operational uncertainty. An important constraint in commercial actuators is that they provide output feedback only, as they are only equipped with low-cost position sensors. This hurdle has been overcome by introducing observers in the control loop, which estimate other system states from the output feedback. The estimation and control algorithms have been validated in simulation and experimentally on diesel engine test benches.

The McTronX research group, at the Potchefstroom campus of the North–West University, has been researching Active Magnetic Bearings (AMBs). A fully suspended, flywheel energy storage system (FESS) has been developed. Due to excessive unbalance on the rotor, the motor drive could not be tested up to its rated speed. In the interim, until the rotor can be balanced and other rotor dynamic effects have been investigated, the group decided that the existing drive control should be improved and tested on a high–speed permanent magnet synchronous motor (PMSM), using normal roller element bearings. In order to test the motor control a second (identical) PMSM, mechanically coupled to the former, operates in generator mode which serves as the torque load. Two different control algorithms, namely V/f and vector control, are designed and implemented on a rapid control prototyping system, i.e. dSPACE®. The V/f control is an open–loop, position sensorless technique, whilst the vector controller makes use of a position sensor. From the design and implementation it became clear that the vector control is more robust, in the sense that it is less sensitive on parameter variations and disturbances. It can start up reliably even under full load conditions. The V/f control is an attractive alternative to the vector control, especially in AMB systems, where it may be difficult to mount the position sensor, has to operate in a hazardous environment not suited to the sensor or could degrade the reliability of the AMB system. The cost of the position sensor is not really a concern compared to the cost of an AMB system. The V/f control is more suited to fan and pump applications, which has a low dynamic requirement. The V/f control has high startup currents and is not recommended for applications requiring a high starting torque or fast acceleration during operation. The inverter, which drives the PMSM, also had to be developed. With regard to the motor control, the effects of inverter non–idealities had to be accounted, especially for the V/f control. The implemented control algorithms were tested up to 20 krpm. Discrepancies between the expected and actual results are discussed. Overall, the controllers performed as desired. Generally, the project goals have been reached satisfactorily. / Thesis (M.Ing. (Computer and Electronic Engineering))--North-West University, Potchefstroom Campus, 2011.

The McTronX research group, at the Potchefstroom campus of the North–West University, has been researching Active Magnetic Bearings (AMBs). A fully suspended, flywheel energy storage system (FESS) has been developed. Due to excessive unbalance on the rotor, the motor drive could not be tested up to its rated speed. In the interim, until the rotor can be balanced and other rotor dynamic effects have been investigated, the group decided that the existing drive control should be improved and tested on a high–speed permanent magnet synchronous motor (PMSM), using normal roller element bearings. In order to test the motor control a second (identical) PMSM, mechanically coupled to the former, operates in generator mode which serves as the torque load. Two different control algorithms, namely V/f and vector control, are designed and implemented on a rapid control prototyping system, i.e. dSPACE®. The V/f control is an open–loop, position sensorless technique, whilst the vector controller makes use of a position sensor. From the design and implementation it became clear that the vector control is more robust, in the sense that it is less sensitive on parameter variations and disturbances. It can start up reliably even under full load conditions. The V/f control is an attractive alternative to the vector control, especially in AMB systems, where it may be difficult to mount the position sensor, has to operate in a hazardous environment not suited to the sensor or could degrade the reliability of the AMB system. The cost of the position sensor is not really a concern compared to the cost of an AMB system. The V/f control is more suited to fan and pump applications, which has a low dynamic requirement. The V/f control has high startup currents and is not recommended for applications requiring a high starting torque or fast acceleration during operation. The inverter, which drives the PMSM, also had to be developed. With regard to the motor control, the effects of inverter non–idealities had to be accounted, especially for the V/f control. The implemented control algorithms were tested up to 20 krpm. Discrepancies between the expected and actual results are discussed. Overall, the controllers performed as desired. Generally, the project goals have been reached satisfactorily. / Thesis (M.Ing. (Computer and Electronic Engineering))--North-West University, Potchefstroom Campus, 2011.

Robustness of the closed-loop system has repercussions on both stability and performance, making the study of robustness very important. Fundamentally, the performance and stability of closed-loop systems utilizing state-feedback are tied to that of the observers. The primary goal of this thesis is to develop a robust nonlinear observer and closely examine the usefulness of the observer in the presence of non-collocation and parametric uncertainty and as an integral component in closed-loop control. The usefulness of the observer being investigated depends on robustness, accuracy, computational burden, tunability, ease of design, and ease of implementation on an actual flexible motion system. The design and subsequent integration of the Kalman filter, an optimal observer, into a closed-loop system is well known and systematic. However, there are shortcomings of the Kalman filter in the presence of model uncertainty which are highlighted in this work. Simulation studies are conducted using the Simulation Module in National Instruments LabVIEW 8.5 and experiments are conducted on a physical system consisting of a single flexible link with non-collocation of actuators and sensors using LabVIEW Real Time 8.5. Simulations serve as a means to analyze the performance of the optimal observer and the robust observer by analyzing their dynamic behavior as well as that of the closed-loop system with each observer in place. The focus of experiments is on investigating implementation of the robust observer, including initialization and tuning of observer design parameters off-line and on-line. Simulations verify the robustness properties of the sliding mode observer while experiments show that the robust observer can be implemented at fast control rates and that replacing the Kalman filter with a robust observer has direct ramifications on closed-loop performance.

Neste trabalho é apresentado o desenvolvimento de um sistema de posicionamento dinâmico para uma pequena embarcação baseado em controle a estrutura variável com realimentação por visão computacional. Foram investigadas, na literatura, diversas técnicas desenvolvidas e escolheu-se o controle a estrutura variável devido, principalmente, ao modo de acionamento dos propulsores presentes no barco utilizado para os experimentos. Somando-se a isto, foi considerada importante a robustez que a técnica de controle escolhida apresenta, pois o modelo utilizado conta com incerteza em sua dinâmica. É apresentado ainda o projeto da superfície de deslizamento para realizar o controle a estrutura variável. Como instrumento de medição optou-se por utilizar técnicas de visão computacional em imagens capturadas a partir de uma webcam. A escolha por este tipo de sistema deve-se a alta precisão das medições aliada ao seu baixo custo. São apresentadas simulações e experimentos com controle a estrutura variável em tempo discreto utilizando a integral do erro da posição visando eliminar o erro em regime. Para realizar o controle que demanda o estado completo, são comparados quatro estimadores de estado realizados em tempo discreto: derivador aproximado; observador assintótico com uma frequência de amostragem igual a da câmera; observador assintótico com uma frequência de amostragem maior que a da câmera; e filtro de Kalman. / The design of a dynamic positioning system for a small boat based on variable strutucture control and visual-servoing is presented. Many control tecniques have been investigated and the variable structure control was chosen, mainly, due the operation mode of the motor drivers installed on the boat applied in the experiments. The robustness of this control technique was also considered since the available dynamic model of the boat is uncertain. The design of the sliding surface is shown as well. Computer vision techniques were used to measure the position of the boat from images taken with a webcam, this kind of measure system was chosen due to its high accuracy and low cost. Simulation and experimental results of discrete time variable structure control with integral action of the boats postion, included in order to eliminate steady state error, are shown. To develop this controller four state estimators, in discrete time, are compared: derivative of position; asymptotic observer at a high sampling rate; asymptotic observer at webcams sampling rate; and Kalman filter.

Orientador: Gilberto Pechoto de Melo / Resumo: No decorrer dos anos, alguns métodos de manutenção têm sido desenvolvidos para evitar que falhas em estruturas e maquinários possam ocorrer e desencadear paradas inesperadas ou desnecessárias. Os observadores de estado podem reconstruir os estados não medidos do sistema, desde que o mesmo seja observável, tornando possível, desta forma, estimar as medidas nos pontos de difícil acesso. A técnica dos observadores de estado consiste em desenvolver um modelo para o sistema em análise e comparar a estimativa da saída com a saída medida, a diferença entre os dois sinais presentes resulta em um resíduo que é utilizado para análise. Neste trabalho foi montado um banco de observadores associado a um modelo de trinca em placa de Kirchhoff de modo a acompanhar o progresso da mesma. Foram analisados quatro sistemas mecânicos contendo placas, sendo estes um sistema computacional de placa sobre elementos de molas e amortecimento, um sistema computacional de placa engastada livre com ausência ou presença de trinca, um sistema experimental de placa engastada livre com ausência ou presença de entalhe e um sistema experimental de placa engastada livre com ausência ou presença de massa extra. Novamente, o banco de observadores é utilizado para detecção da falha na estrutura. Os resultados obtidos através de simulações computacionais em uma viga engastada discretizada pela técnica dos elementos finitos e as análises experimentais realizadas foram bastante satisfatórios, validando a metodologia d... (Resumo completo, clicar acesso eletrônico abaixo) / Mestre

De nos jours, la plupart des véhicules sont équipés de Directions Assistées Electriques (DAE). Ce type de systèmes d'aide à la conduite permet de réduire les efforts que le conducteur doit fournir pour tourner les roues. Ainsi, grâce à un moteur électrique, la DAE applique un couple additionnel en accord avec le comportement du conducteur et la dynamique du véhicule. Il est donc nécessaire de développer une commande en couple basée en particulier sur le signal provenant d'un capteur mesurant le couple agissant au niveau de la barre de torsion (correspondant à une image du couple conducteur). Ce composant est donc essentiel au fonctionnement de la DAE. Or, une défaillance de ce capteur entraine le plus souvent une coupure de l'assistance, pouvant mener à un risque d'accidents. Au regard de la sécurité fonctionnelle, un développement d'un mode de sécurité est recommandé, par de plus en plus de constructeurs automobiles. D'autre part, le marché des équipementiers automobiles reste un secteur très concurrentiel où une baisse des coûts de production est un challenge constamment recherché afin de gagner de nouvelles parts de marchés. Cet aspect de réduction du nombre de capteurs et d'analyse de la dynamique du véhicule s'inscrit donc dans le prolongement de la stratégie de sécurité. Cette thèse, menée au sein de JTEKT Europe, aborde ces divers enjeux. Après une présentation des différents systèmes de directions assistés électriques, des modèles sont présentés pour être utilisés lors de la conception de lois de commande et d'estimateurs. Ensuite deux méthodes d'estimation du couple conducteur sujet aux perturbations de la route et aux bruits de mesures sont proposées : la première est un observateur proportionnel intégral (PI) à synthèse mixte $H_infty/H_2$, et la seconde une approche par filtrage $H_infty$. Puis plusieurs stratégies de commande sont proposées suivant deux cas de figures distincts, soit en utilisant un observateur PI qui estime les états du système et le couple conducteur (LQR, commande LPV par retour d'état), soit en faisant abstraction d'estimateur de couple conducteur (commande $H_infty$ par retour de sortie dynamique). Ce dernier aspect présente l'avantage de nécessiter moins de mesures que le précédent. Ces approches ont été validées en simulation et mises en œuvre sur un véhicule prototype où des résultats prometteurs ont été obtenus. / Nowadays, modern vehicles are equipped with more and more driving assistance systems, among them Electric Power Steering (EPS) helps the driver to turn the wheels. Indeed, EPS provides through an electric motor, an additional torque according to the driver's behaviour and the vehicle's dynamics to reduce the amount of effort required to the driver. Therefore, a torque control is developed based on the torque sensor signal which measures in practice the torsion bar torque (corresponding to an image of the driver torque). Consequently, this component is essential to the functioning of EPS systems.Indeed, a torque sensor failure usually leads to shut-off the assistance which may increase the risk of accident. Regarding functional safety, a back-up mode is recommended and required by more and more car manufacturers. On the other hand, a major challenge for automotive suppliers is to reduce cost production in order to meet growing markets demands and manage in the competitive sector. This issue considering a reduction of sensors' numbers and analysis of vehicle's dynamics is therefore an extension of applying the safety strategy. This thesis, carried out within JTEKT Europe, addresses these various issues.After introducing an overview of the different EPS systems, some models used for the design of controllers and estimators are presented. Then, two methods to estimate the driver torque subject to road disturbances and noise measurements are proposed: the first is a proportional integral observer (PI) with mixed synthesis $H_infty / H_2 $, whereas the second is an $ H_infty $ filtering approach. Then, several control strategies are proposed according to two different cases, either by using a PI observer which estimates the system states and the driver torque (LQR, LPV feedback control) or by not taking into account the driver torque estimation ($ H_infty $dynamic output feedback control). This latter approach has the advantage to require less measurements than the previous one. These approaches have been validated in simulation and implemented on a prototype vehicle where promising results have been obtained.

Cette thèse porte sur la conception d’une classe particulière d’estimateurs d'état, les observateurs intervalles. L’objectif est d’estimer de manière garantie, les bornes supérieure et inférieure de l’ensemble admissible de l'état d’un système, à chaque instant de temps. L’approche considérée repose sur la connaissance a priori du domaine d’appartenance, supposé borné, des incertitudes du système (incertitudes de modélisation, perturbations, bruits, etc). Une classe d'observateurs intervalles à entrées inconnues est proposée pour la classe des systèmes Linéaires à Paramètres Variants (LPV). La synthèse des paramètres de l’observateur repose sur la résolution d’un problème d’optimisation sous contraintes de type inégalités matricielles linéaires (LMI) permettant de garantir simultanément les conditions d’existence de l’observateur ainsi qu’un niveau de performance, soit dans un contexte énergie, soit dans un contexte amplitude ou soit dans un contexte mixte énergie/amplitude. Plus particulièrement, la performance de l'observateur repose sur une technique de découplage pour annuler les effets des entrées inconnues et une technique d’optimisation destinée à minimiser, au sens de critères de type gain L2et/ou gain L∞, les effets des perturbations sur la largeur totale de l’enveloppe de l'état du système LPV. La méthodologie de synthèse proposée est illustrée sur un exemple académique. Enfin, la méthodologie est appliquée au cas de la phase d’atterrissage du véhicule spatial HL20, sous des conditions de simulations réalistes. / This thesis addresses the design of a class of estimator, named interval obser-ver, which evaluates in a guaranteed way, a set for the state of the system at each instant of time. The proposed approach is based on a priori knowledge of bounded sets for the system uncertainties (modeling uncertainties, disturbances, noise, etc.). A methodology to design an interval observer is proposed for the class of Linear Parameter Varying (LPV) Systems. The feasibility of the latter is based on the resolution of linear Matrix Inequalities (LMI) constraints allowing to simultaneously get the existence conditions of the intervalobserver and a certain level of a priori given performance for the state estimation of the system. Specifically, the performance of the estimates is based on a decoupling technique to avoid the effects of unknown inputs and an optimization technique to minimize, in the L2 and/or L∞ gain sense, the effects of disturbances on the estimated interval length for the state of the LPV system. The design methodology is illustrated on academic examples.Finally, the methodology is applied on the landing phase of the HL20 shuttle.

Autotélico traz uma reflexão acerca das estruturas que constituem a linguagem poética com a qual trabalho. No decorrer dos anos percebi que as obras vêm se organizando através de regras próprias, relações estabelecidas no processo poético entre os conceitos de objeto, mitologia, construções narrativas cinemáticas e um espaço polissêmico manipulado pelo observador. Elementos heteróclitos que tendem a se interconectar e constituir um todo auto-organizado, através da regulação de um sistema unificador e coordenador dos elementos. Através da análise e reflexão sobre as principais obras em minha trajetória, permeada por questões teóricas e contrapontos com outras áreas, desenvolvo um pensamento sobre a obra como forma de instauração de realidades e apresento a idéia de uma estrutura poética como um processo contínuo de reconstrução, um sistema aberto em mutação, que tende a criar o ambiente material e teórico para novas reconfigurações ampliadas. Essa dissertação age, então, como uma ferramenta de mapeamento dos métodos de criação de sistemas para a instauração da obra artística, onde cada obra se apresenta una e múltipla, sinédoque de suas possibilidades, criando universos poéticos que se bifurcam e se transformam. / Autotélico (Autotelic) presents a reflection about the structures of the poetic language in the author‟s work. Over the years the artworks have been organizing themselves through relationships established during poetic process between object concepts, mythology, cinematic narrative constructions and a polysemic space manipulated by the observer. Eccentric elements tend to interconnect to create an organized whole through an adjuster system in itself. The most important works in the author‟s portfolio were analyzed with the related theory and other areas‟ counterpoints. The ideas of artworks as a reality establisher and a poetic structure as a continuous process of rebuild and mutation are developed. This dissertation brings a kind of mapping tool of the conception methods where each work is unique and multiple creating poetic universes that are in touch and in transformation.