A retroalimentação de controladores preditivos que utilizam modelos em espaço de estado pode ser realizada de duas formas: (a) correção por bias, em que as saídas preditas são corrigidas adicionando-se um valor proporcional a discrepância encontrada entre o valor medido atual e sua respectiva predição e por (b) retroalimentação dos estados, onde se determinam as condições iniciais através da estimação dos estados, e a partir de uma melhor condição inicial se realizam as predições futuras usadas no cálculo das ações de controle. Nesta dissertação estas duas abordagens são comparadas utilizando a Planta Laboratorial de Seis Tanques Esféricos. As técnicas de Filtro de Kalman Estendido (EKF) e Filtro de Kalman Estendido com Restrições (CEKF) foram empregadas para estimar os estados não medidos. Inicialmente foram feitos testes off-line destes algoritmos de estimação. Para estes testes são utilizados uma série de dados da planta laboratorial do estudo de caso, na qual são estudadas as influências de diversos fatores de ajuste que determinam a qualidade final de estimação. Estes ajustes serviram de base para a aplicação destes algoritmos em tempo real, quando então, estimadores de estados estão associados ao sistema de controle do processo baseado em um algoritmo de controle preditivo. Após se ter certificado a qualidade das estimações de estado, partiu-se para sua utilização como uma alternativa de retroalimentação de controladores preditivos. Estes resultados foram comparados com os obtidos através da correção simples por bias. Os resultados experimentais apontam para uma marginal piora devido à retroalimentação por estimadores de estados frente à correção por bias, pelo menos para o caso do controlador preditivo linear utilizado na comparação. Entretanto, espera-se que resultados melhores sejam obtidos no caso de modelos preditivos não-lineares, uma vez que nestes casos o modelo é bem mais sensível à qualidade da condição inicial. / The feedback of controllers that use predictive models in state space can be accomplished in two ways: (a) bias correction, where the predicted outputs are corrected by adding a value proportional to the discrepancy found between the current measurement and its respective prediction; and by (b) state feedback, which establishes the initial conditions through the states estimation, and from a better initial condition are carried out the future predictions used in the calculation of control. In this thesis these two approaches are compared using a Laboratorial Plant of Six Spherical Tanks. The techniques of Extended Kalman Filter (EKF) and Constraint Extended Kalman Filter (CEKF) were used to estimate the unmeasured states. Initially, tests were carried out off-line for theses estimation algorithms. For such testing are used a dataset of the plant in case study, in which are studied the influences of several adjustment factors that they determine the final quality of estimation. These adjustments were used of base for the application of these algorithms in real time, when then state estimators are associated with the system of process control based on a predictive control algorithm. After having ascertained the quality of the state estimates, begins its use as an alternative for feedback of predictive controllers. These results were compared with those obtained by the simple correction of bias. The experimental results show a marginal worsening due to feedback from state estimated compared with bias correction, at least for the case of linear predictive controller used in the comparison. However, one expects that better results will be obtained in the case of non-linear predictive models, since in these cases the model is much more sensitive to the quality of the initial condition.

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Includes bibliography. / Successful multivariable control system design demands knowledge, skill and creativity of the designer. The goal of the research described in this dissertation was to investigate, implement, and evaluate methods by which artificial intelligence techniques, in a broad sense, may be used in a design system to assist the user. An intelligent, interactive, control system design tool has been developed to fulfil this aim. The design tool comprises two main components; an expert system on the upper level, and a powerful CACSD package on the lower level. The expert system has been constructed to assist and guide the designer in using the facilities provided by the underlying CACSD package. Unlike other expert systems, the user is also aided in formulating and refining a comprehensive and achievable design specification, and in dealing with conflicts which may arise within this specification. The assistance is aimed at both novice and experienced designers. The CACSD package includes a synthesis program which attempts to find a controller that satisfies the design specification. The synthesis program is based upon a recent factorization theory approach, where the linear multivariable control system design problem is translated into, and techniques efficiency solved as, a quadratic programming problem, which significantly improve the time and space of this method have been developed, making it practical to solve substantial multivariable design problems using only a microcomputer. The design system has been used by students at the University of Cape Town. Designs produced using the expert system tool are compared against those produced using classical design methods.

Les actionneurs piézoélectriques sont très utilisés pour les systèmes de positionnement pour des tâches à l'échelle micro/nanométrique en raison de leur haute résolution (sub-micrométrique), leur grande bande passante, et une densité de force élevée. Cependant, ils sont caractérisés par des non-linéarités telles que l'hystérésis et la dérive lente, par une grande sensibilité à l’environnement, et pour certains par des comportements oscillatoires. Ces caractéristiques ont un impact considérable sur les tâches que ces actionneurs doivent effectuer et leur contrôle reste souvent difficile. Différents correcteurs robustes ont été développés pour contrôler les actionneurs piézoélectriques. Il s'agit notamment de l'approche grand gain, des approches H-inf, des approches de contrôle basée sur l'observation des perturbations, ...etc. Ces techniques ont démontré une amélioration significative des performances mais mènent souvent à des correcteurs d'ordre élevé qui sont difficiles à mettre en œuvre. Cette thèse consiste à développer des correcteurs pour des actionneurs piézoélectriques en combinant l'analyse d'intervalle et les techniques classiques de commande.Les avantages principaux d’utiliser des intervalles est qu'ils permettent de modéliser facilement les incertitudes paramétriques en les limitant par des bornes. Par ailleurs, les travaux existants démontrent qu’il est possible de synthétiser de manière plus simplifiée des correcteurs robustes d’ordre faible, c-à-d ordre inférieur à celui du modèle. L'état de l'art sur l'utilisation des techniques par intervalle pour la synthèse de correcteurs peut être présenté en deux catégories : les techniques par intervalle basées sur des fonctions de transfert, et les techniques par intervalle basées sur la représentation d’état. Les techniques par intervalle basées sur les fonctions de transfert sont actuellement limitées pour modéliser et synthétiser des correcteurs pour des systèmes monovariables incertains tandis que les techniques basées sur la représentation d'état sont bien adaptées pour des systèmes multivariables incertains. Néanmoins, ces travaux existants pour des systèmes multivariables sont limités aux modèles avec des matrices d'état et d'entrée de structures spéciales. En outre, elles ne portent que sur le degré de stabilité du système en boucle fermée et ne prennent pas donc en compte des spécifications sur les performances. Cette thèse développe des outils de synthèse de correcteurs robustes pour des systèmes multivariables à incertitudes paramétriques dans l’approche d’état par intervalle sans structure particulière et en considérant à priori des performances. Des validations expérimentales sur différents actionneurs piézoélectriques, et ce en commande en position et en force, sont efféctuées. Enfin, la thèse propose également l’extension des observateurs à entrée inconnue pour les systèmes par intervalle afin de compléter les techniques de commande proposées. / Piezoelectric actuators are widely used at micro/nanoscale because of their simpleconfiguration, high resolution (sub-nanometric), high speed (large bandwidth upto 1kHz), and high force density. However, they are characterized by some nonlinearitiessuch as hysteresis, internal friction and creep,...etc. These characteristicsconsiderably impact the dynamics of the piezoactuators which makes the controlof these systems not a trivial task. Various robust controllers have been developedto control piezoelectric actuators. These include high gain feedback approach, H1approach, disturbance observer based control approach,...etc. Those techniquesdemonstrated a significant improvement of the control performance, but they oftenderive controllers with high-order which are difficult for implementation. Tobypass this limitation, we focus on the thesis on combining interval analysis withclassical controller design techniques to obtain a low order controllers. The mainadvantage of intervals is that they permit to model parametric uncertainties easilyby bounding them. Furthermore, the process of modeling the system uncertaintiesby intervals makes the synthesis of robust controller with low order relatively easy.The state of the art on the use of interval techniques to design and derive robustcontrollers for uncertain system can be divided into two categories: intervaltransfer functions based approaches and interval state-space representation basedapproaches. Interval transfer functions based designs have been widely used tomodel and to control SISO (Single Input single Output) systems subjected to uncertainties.These approaches make the synthesis of robust controllers for suchsystems easy with providing good performance. However, the current work thatuse interval transfer functions are limited to systems in SISO case. In the otherside, the state-space based approaches have been shown to be well adapted tosynthesis robust controllers for multivariable systems. Nevertheless, the excitingworks are limited to systems with state and input matrices of special structures.Furthermore, they address only the degree of stability of the closed-loop systemwithout discussing performance specification. In order to make the design of robustcontroller using interval state-space approach possible for any interval state-spacestructure, this thesis will explore the interval state-space control design using robustpole assignment technique. This proposed approach will guarantee the stability and the desired performance of the closed-loop system also it allows to obtaina low order controller.For this matter, an algorithm based on Set Inversion Via Interval Analysis(SIVIA) combined with interval eigenvalues computation is proposed to seek for aset of robust gains. This recursive SIVIA-based algorithm allows to approximatewith subpaving the set solutions [K] that satisfy the inclusion of the eigenvaluesof the closed-loop system in a desired region in the complex plan. Furthermore,simple algorithms are proposed to find the optimal feedback gains among the rangeof robust gains [K] as well as the range of the gains that satisfy input constraints,all with the help of interval analysis. Finally, in order to improve the controllerperformance, we were directed our attention to nonlinear control approaches andespecially interval sliding mode control (ISMC) design using interval observers.The effectiveness of the proposed approaches are tested by a real experimentationon several platforms developed in our laboratory to achieve robust performance.

The purpose of this study was to explore the relationships between and among various demographic and test score data with American College Testing (ACT) scores in 281 Tennessee high schools. This study also addressed which high school characteristics were related to the number of students meeting the ACT requirement for Tennessee lottery scholarships. In addition, this study examined Tennessee Value Added Assessment System's (TVAAS) assessment of ACT scores and its distribution of grades to Tennessee's high schools based upon its Value-Added analysis. The researcher performed correlations and multivariable linear regressions using socioeconomic status, ethnicity, dropout rate, graduation rate, attendance, average daily membership, per-pupil expenditure, teacher salary, Gateway exams, English I scores, and math foundations scores as independent variables and ACT scores as the dependent variable. The strengths of the correlations were examined and the best combination of independent variables was used to predict future ACT scores. Schools were divided into quartiles, based upon average daily membership and attendance rates, in order to analyze the differences in r2 values among the quartiles when running regressions to predict ACT scores. Quartiles, based upon the percentage of students qualifying for free/reduced meals, ethnicity, and average daily membership were used to study the difference in TVAAS' grade distribution based upon its assessment of ACT scores. The findings indicated that English I and II scores are most strongly associated with ACT composite scores including the four ACT subtests: math, English, reading, and science. English scores were found to be more strongly associated with ACT math scores than Algebra I scores and more strongly associated with ACT science scores than biology scores. It was found that the 21 composite ACT score requirements of Tennessee's lottery scholarships predominantly favored Caucasian students who did not qualify for free/reduced-priced meals. It was also discovered that TVAAS' ACT grades were unevenly distributed when schools were divided into quartiles based upon the percentage of students qualifying for free/reduced-priced meals, ethnicity, and average daily membership. Only one school in the quartile containing the schools with the highest percentage of students qualifying for free/reduced-priced meals scored above the state's average gain in the reading section of the ACT test.

[EN] To obtain the market value for urban properties, the following is necessary for the decision making in different scenarios: in case of dealing with financial institutions, the focus will be in acquiring knowledge of the value of the property to finance a mortgage. One of the different government orders are to collect property taxes, so this profit will serve as the foundation for proceedings before public and private organizations. For an accurate estimate of the price or value that will describe the market conditions, it is necessary to build models that will be capable of calculating such value. The synthetic methods that currently use a minor amount of information are the ones that are mostly used by appraisers, as well as the econometric models. Also, they are considered as the concept of multiple linear regression that utilize abundant observations. In reality the econometric models are a generalization of synthetic methods. On the other hand, artificial neural networks and in particular the multi-layer network, can be an alternative for a price estimate. Currently a comparison is being performed between the selected econometric model and the neural network, revealing that the networks give a better outcome for price estimates. This study has been achieved in Morelia, Michoacán, Mexico for several housing segments. / [ES] Obtener el valor de mercado para inmuebles urbanos es necesario para la toma de decisiones en diferentes escenarios: tratándose de instituciones financieras, su interés radica en conocer este valor para el financiamiento de préstamo con garantía hipotecaria, a los diferentes órdenes de gobierno para cobrar los impuestos catastrales, así este valor servirá de base para la realización de diferentes trámites ante entidades públicas o particulares. Para una buena estimación del precio o valor que explique las condiciones del mercado, es necesario construir modelos capaces de estimar dicho valor. Actualmente los métodos sintéticos que usan información escasa son los más utilizados por los tasadores, así como los modelos econométricos -también denominados con el concepto de regresión lineal múltiple- que usan muchas observaciones, en realidad los modelos econométricos son una generalización de los métodos sintéticos. Por otro lado, las redes neuronales artificiales, y en concreto la red multicapa, pueden ser una alternativa para la estimación del precio. En el presente se realiza una comparativa entre el modelo econométrico seleccionado y la red neuronal, demostrando que las redes obtienen mejores resultados en la estimación de precio. El estudio se ha realizado en la ciudad de Morelia, Michoacán, México, para varios segmentos de vivienda. / [CA] Obtindre el valor de mercat per a immobles urbans és necessari per a la presa de decisions en diferents escenaris: tractant-se d'institucions financeres, el seu interès està en conèixer aquest valor per al finançament de préstec amb garantia hipotecària, als diferents ordres de govern per cobrar els impostos cadastrals. Així aquest valor servirà de base per a la realització de diferents tràmits davant entitats públiques o particulars. Per a una bona estimació del preu o valor que expliqui les condicions del mercat, cal construir models capaços d'estimar aquest valor. Actualment els mètodes sintètics que fan servir informació escassa són els més utilitzats pels valuadors, així com els models economètrics -també denominats de regressió lineal múltiple, que fan servir moltes observacions. En realitat els models economètrics són una generalització dels mètodes sintètics. D'altra banda, les xarxes neuronals artificials, i en concret la xarxa multicapa, poden ser una alternativa per a l'estimació del preu. En el present treball es realitza una comparativa entre el model economètric seleccionat i la xarxa neuronal, demostrant que les xarxes obtenen millors resultats en l'estimació de preu. L'estudi s'ha realitzat a la ciutat de Morelia, Michoacán, Mèxic, per a diversos segments d'habitatge. / Preciado Carrillo, JC. (2016). Valoración de inmuebles urbanos comparativa modelo regresión multivariable versus redes neuronales artificiales para la ciudad de Morelia Michoacán, México [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/62202

The ankle joint complex is a common source of injury for various demographics and is often observed during gait analysis. I investigate using soft robotic sensors as a means for collecting kinematic data at the ankle joint complex. I validate the linearity of these sensors by measuring stretch against extension and against stretch from frontal and sagittal planar foot movements using a wooden ankle mockup. I then conduct a study involving ten participants who perform repetitive trials of four foot movements (plantarflexion, dorsiflexion, inversion and eversion) using ten different locations. Four optimal locations were identified for these movements based on linearity, accuracy, robustness, and consistency. Lastly, I validated soft robotic sensors against the human gait cycle. Twenty participants were recruited and performed twelve trials, walking across a flat surface and a cross-sloped surface while motion capture data and soft robotic sensor data was collected.

This thesis presents the design and implementation of control strategies for building energy management systems (BEMS). The controllers considered include the multi PI-loop controllers, state-space designs, constrained input and output MIMO adaptive controllers, fuzzy logic solutions and genetic algorithm techniques. The control performances of the designs developed using the various methods based on aspects such as regulation errors squared, energy consumptions and the settling periods are investigated for different designs. The aim of the control strategy is to regulate the room temperature and the humidity to required comfort levels. In this study the building system under study is a 3 input/ 2 output system subject to external disturbances/effects. The three inputs are heating, cooling and humidification, and the 2 outputs are room air temperature and relative humidity. The external disturbances consist of climatic effects and other stochastic influences. The study is carried out within a simulation environment using the mathematical model of the test room at Loughborough University and the designed control solutions are verified through experimental trials using the full-scale BMS facility at the University of Bradford.

This master’s thesis examines how a small MIMO lighting system can be identified and controlled. Two approaches are examined and compared; the first approach is a dynamic model using state space representation, where the system identification technique is Recursive Least Square, RLS, and the controller is an LQG controller; the second approach is a static model derived from the physical properties of light and a feedback feed-forward controller consisting of a PI controller coupled with a Control Allocation, CA, technique. For the studied system, the CA-PI approach significantly outperforms the LQG-RLS approach, which leads to the conclusion that the system’s static properties are predominant compared to the dynamic properties.

Este trabalho apresenta o controle de posição e orientação de um modelo não linear de Plataforma de Stewart com seis graus de liberdade construído no ambiente de sistemas multicorpos ADAMS® desenvolvido pela Mechanical Dynamics, Inc. O modelo não linear é exportado para o ambiente SIMULINK® desenvolvido pela MathWorks, Inc., onde o controle de posição e orientação é realizado a partir da linearização do modelo e a aplicação de um sistema seguidor com realimentação de estados. Utililiza-se, também o SIMULINK® para implementar a dinâmica de um sistema servoválvula e cilindro hidráulico com um servocontrole de pressão e assim simular o comportamento dinâmico de um simulador de vôo com acionamento hidráulico. A utilização destes pacotes comerciais visa obter uma economia de tempo e esforço na modelagem de sistemas mecânicos complexos e na programação para obtenção da resposta do sistema no tempo, além de facilitar a análise de várias configurações de Plataformas de Stewart / This work shows the position and orientation control of a non-linear model of a Stewart platform with six degree of freedom developed in the multibody systems environment ADAMS® (Mechanical Dynamics, Inc.). The non-linear model is exported to SIMULINK® (MathWorks, Inc.), where the position and orientation control is accomplished using the linear model and applied as a tracking-system with state-feedback. The SIMULINK® is also used to implement the dinamics of the servovalve and hydraulic cylinder with pressure-control servo and so simulate the dynamic behavior of the flight simulator with hydraulic drive. These commercial packages are used seeking to save time and effort in the modeling of complex mechanical systems and in the programming to get the time response of the system, facilitating the analysis of several Stewart Platforms configurations.