Дисертації з теми "Contrôle de quadrator"
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Wang, Siyuan. "Contôle homogène de quadrator : théorie et expérience." Thesis, Centrale Lille Institut, 2020. http://www.theses.fr/2020CLIL0026.
Анотація:
Au cours des dernières décennies, les problèmes liés au contrôle des quadrotors attirent plus d'attention des chercheurs par rapport aux autres véhicules volants. Cependant, la plupart des produits commerciaux utilisent encore le contrôleur PID linéaire, qui offre une performance suffisamment bonne. Le développement d'un contrôleur, qui pourrait convaincre l'industrie de l'utiliser à la place du contrôleur PID linéaire, reste toujours un défi. L’objectif de cette thèse est de montrer que le contrôleur homogène est une alternative au contrôleur PID linéaire. Pour ce faire, une nouvelle méthode est proposée : mettre à niveau de l'algorithme linéaire vers un algorithme homogène. Elle utilise les avantages du contrôleur / observateur linéaire fournis par le constructeur pour le réglage de l'algorithme homogène. Les résultats expérimentaux soutiennent les développements théoriques et confirment une amélioration significative de la qualité du contrôle du quadrotor: meilleure précision, plus de robustesse et réponse plus rapideIn the past several decades, quadrotor control problems attract more attentions of the researcher comparing withother flying vehicles. However, most of the commercial products still use linear PID controller, which provides sufficientlygood performance. Development of a controller, which would convince theindustry to use it instead of linear PID, is still a challenge. The aim of this thesis is to show that homogeneous controller is a possiblealternative to linear one. For this purpose, a new methodof upgrading linear algorithm to homogeneous one is proposed. It uses the gains of linear controller/observer provided by the manufacturer for tuning of homogeneous algorithm. The experimental results support the theoretical developments and confirm a significant improvement of quadrotor’s control quality:better precision, more robustness and faster response
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Felão, Luiz Henrique Vitti. "High gain approach and sliding mode control applied to quadrature interferometer /." Ilha Solteira, 2019. http://hdl.handle.net/11449/190782.
Анотація:
Orientador: Cláudio KitanoAbstract: Interferometers are extremely sensitive measurement devices, which use the principle of interference between two or more sources of light to generate a pattern of constructive and destructive interference. This pattern contains information about the physical phenomenon under study, and their light intensity can be used to calculate the optical path difference traveled by the two beams. The optical path difference and light intensity relationship is given by a cosine type function. Large disturbances can change the interferometer operation point, reaching nonlinear regions of the interferometric curve and even inducing ambiguities due to the periodicity of the input/output relationship. The present work concerns with the modeling, development and application of a control strategy based on sliding mode control, in a two-beam quadrature interferometer. It was used the high gain approach, which consists in to fully compensate the phase shifts induced on the sensor arm with the control system, in such a way that the voltage control signal becomes proportional to the phase disturbances. Therefore, the demodulation process does not require phase unwrapping algorithms. This implemented system showed capability to improve dynamic range and bandwidth when compared with other control systems in literature that were based on different high gain approach topologies. Also a new method of interferometric phase demodulation is proposed allying this control strategy to a virtual emulated inte... (Complete abstract click electronic access below)
Resumo: Interferômetros são dispositivos de medição extremamente sensíveis, os quais utilizam o princípio de interferência entre duas ou mais fontes de luz para gerar um padrão de interferência construtiva e destrutiva. Este padrão contém informação sobre os fenômenos físicos sob estudo, e sua intensidade luminosa pode ser usada para calcular a diferença de caminho óptico acumulada pelos dois feixes de luz. A diferença de caminho óptico e a intensidade de luz são relacionadas por uma função cossenoidal. Grandes distúrbios podem alterar o ponto de operação do interferômetro, alcançando regiões não lineares da curva característica do interferômetro e até mesmo induzindo ambiguidades, devido à periodicidade da relação entrada/saída. Este trabalho preocupou-se com o modelamento, desenvolvimento e aplicação de uma estratégia de controle baseada em controle com modos deslizantes, em um interferômetro de dois feixes em quadratura. Foi utilizada a abordagem de alto ganho, a qual consiste em utilizar o sistema de controle para compensar completamente os deslocamentos de fase induzidos no braço sensor, de tal forma que o sinal de controle se relaciona com os deslocamentos de fase por uma equação de reta. Portanto o processo de demodulação não necessita de algoritmos de desdobramento de fase. O sistema implementado mostrou capacidade de melhorar a faixa dinâmica e largura de banda quando comparado com outros sistemas de controle na literatura, também baseados na abordagem de alto ganho. Destaca... (Resumo completo, clicar acesso eletrônico abaixo)
Doutor
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Santos, José Eduardo Weber dos. "Método de ajuste para MPC baseado em multi-cenários para sistemas não quadrados." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2016. http://hdl.handle.net/10183/141217.
Анотація:
A utilização de controladores preditivos multivariáveis na indústria de processos cresceu significativamente nos últimos anos principalmente devido à versatilidade e a confiabilidade que essa ferramenta proporciona em termos de controle avançado. No entanto, aspectos relacionados à aplicação prática do que vem sendo desenvolvido no meio acadêmico possui pouca difusão na indústria devido às configurações clássicas adotadas, como sistemas quadrados (com o mesmo número de variáveis controladas e manipuladas), modelos lineares, utilização de setpoint e etc. diferindo daquilo que está disponível e é amplamente utilizado industrialmente: sistemas não-quadrados (geralmente com mais variáveis controladas do que manipuladas), modelos não-lineares e utilização de soft-constraints. Esse trabalho propõe uma metodologia para ajuste dos parâmetros presentes em um controlador preditivo, atento à variedade de algoritmos presentes na indústria de processos. Essa metodologia se baseia na obtenção do melhor desempenho alcançável para cada cenário de um modelo global do processo, atendendo as restrições de Número de Desempenho Robusto relativo (rRPN), Máxima Sensibilidade e restrições nas ações de controle. Baseado em um desempenho que é alcançável, o modelo linear global é escalonado (assim como a planta não-linear) e os pesos que levam o sistema para a melhor condição operacional são estimados. Essa técnica abrange controladores operando em faixas e/ou setpoint e configurações não-quadradas, i.e., com mais variáveis controladas do que manipuladas. A abordagem proposta foi testada em uma planta de quatro tanques esféricos com aquecimento apresentando resultados coerentes, corroborando seu potencial de aplicação industrial.Due to their versatility and reliability, Model Predictive Controllers (MPCs) are the standard solution for advanced process control in the process industry. However, there is a gap between the academic developments and the actual industrial applications, since the most academic studies focus on systems working with set-points and same number of manipulated and controlled variables, whereas the industrial application cope with non-squared configuration usually with several controlled variables in ranging and a reduced number of manipulated variables. This work proposes a tuning methodology for the countable parameters presents in a typical industrial predictive controller, considering the variety of the algorithms presents commercially in the process industry. This methodology is based on the estimation of the best attainable performance for each scenario of the global model of the process, constrained by the relative Robust Performance Number (rRPN), Maximal Sensitivity and restrictions in the control actions. Based on a performance that is attainable, the linear global model is scaled (and the non-linear) and the weights that lead the system to the best operational condition are estimated. This technique covers controllers operating in zones of control and/or set-point tracking and non-square configurations, i.e., with more controlled variables than manipulated. The proposed approach was tested in a Quadruple-Spherical tanks heating system presenting coherent results indicating its potential for industrial applications.
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Barão, Renato Casali. "Algoritmos de controle ótimo quadrático com restrições." Universidade de São Paulo, 1997. http://www.teses.usp.br/teses/disponiveis/3/3139/tde-22032004-194309/.
Анотація:
O objetivo do trabalho é apresentar dois algoritmos para a solução de problemas de controle ótimo quadrático robusto com restrições, dentro de um contexto de controladores preditivos (MPC do inglês Model Predictive Control). Inicialmente apresentamos uma breve introdução aos algoritmos MPC, com ênfase na abordagem do controlador linear quadrático. Em seguida são apresentados os dois algoritmos de interesse, que utilizam técnicas de otimização LMI. Dessa forma as restrições e as incertezas podem ser colocadas em formas computacionalmente tratáveis. Por fim são realizadas simulações e comparações entre esses algoritmos, bem como com técnicas de MPC encontradas na literatura atual.The goal of the work is to present two algorithms for the solution of robust quadratic optimal control problems with restrictions, within a model predictive control (MPC) setup. Initially we present a brief introduction of the MPC algorithms, emphasizing the linear quadratic controller approach. Next the two algorithms of interest, using LMI optimization techniques, are presented. By using this technique the restrictions and uncertainties can be written in a computational way. Finally some simulations and comparisons between these algorithms, as well as with MPC techniques found in the current literature, are performed.
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Cheng, Chun-Min. "Use of linear quadratic and quadratic programming methods in model-based process control /." Thesis, Connect to this title online; UW restricted, 1986. http://hdl.handle.net/1773/9814.
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Castro, Marcelo Hirai. "Processo para obtenção de furos quadrados utilizando máquinas ferramentas CNC com ferramenta em rotação." [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/264536.
Анотація:
Orientador: Amauri HassuiDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica
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Resumo: A inovação é a chave para o diferencial da indústria no mercado competitivo atual. Fazer diferente, melhor e mais barato sempre agrega valor ao produto. Por outro lado, a resistência às mudanças faz parte do comportamento humano, seja na sociedade, ou na indústria. O objetivo principal deste trabalho é estudar a viabilidade de se fazer furos não cilíndricos com uma ferramenta em rotação utilizando máquinas-ferramenta CNC. Estes sempre foram obstáculos na indústria de fabricação pela dificuldade de obtenção. Sendo assim, o processo apresentado nesse trabalho busca usinar um furo quadrado com a mesma configuração de ferramentas e fixação de peças utilizadas para um furo cilíndrico, tão comum à indústria. Isso visa reduzir custos de fabricação e facilitar a obtenção de furos não cilíndricos com os recursos de equipamentos programáveis existentes no chão de fábrica. A partir de um modelo matemático, a máquina é programada para executar movimentos sincronizados entre a rotação e os deslocamentos do eixo da ferramenta. Diversas programações foram testadas em diferentes máquinas ferramenta CNC, com diferentes comandos, com e sem recursos de alta velocidade, com diferentes quantidades de pontos programados, interpolações lineares e circulares. A partir dos experimentos, foram analisadas as configurações das máquinas, a capacidade de execução do controlador numérico instalado, a velocidade desenvolvida pela máquina na operação e a geometria obtida dos furos quadrados. Os experimentos apontam que para executar o furo quadrado, os comandos devem ser capazes de controlar um eixo rotativo como eixo propriamente dito, além de sincronizarem mais três eixos lineares. O crítico para este tipo de operação é a velocidade desempenhada pela máquina, sendo o fator mais significativo, o tempo que o comando precisa para o processamento do bloco de programação, independentemente da ativação de recursos de alta velocidade, interpolações lineares ou circulares. Verificou-se também que quanto maior a quantidade de pontos para compor a trajetória do centro da ferramenta, melhor será a geometria obtida do furo. Sendo assim, as máquinas ferramenta CNC que estão em operação na indústria são capazes de realizar a furação não cilíndrica de forma muito próxima à furação cilíndrica quanto ao tempo de usinagem e ao sistema de fixação da ferramenta e da peça, sendo necessária uma programação sincronizada do eixo spindle presente em toda e qualquer máquina ferramenta
Abstract: The innovation is the key for the differential of the industry on the competitive market nowadays. To make different, better and cheaper always it is worth a lot to the product. By the other side, the resistance to changes makes part of the human behavior, in society, or in the industry. The main goal of this work is to study the feasibility to machining of non-cylindrical holes by a tool in rotation using CNC machine tools. That always has been offering obstacles to manufacturing industry by the difficulty of fabrication. Thus, the process presented on this work will machining a square hole with the same configuration of tools and systems for fixation of the parts, used for a cylindrical drilling, so common to industry. This intends to reduce the costs of fabrication and make easier to get non-cylindrical drilling using resources of the programmable equipment which are working at the shops. From a math model on, the machine is programmed to execute synchronized movements between the rotation and the displacements of the axis of the tool. Different programs were tested in different CNC machine tools, with different controllers, with and no resources for high speed, with different quantity of programmed points, with linear and circular interpolations. From the experiments, it was analyzed the configuration of the machines, the capacity for execution of the controller installed, the speed developed by machine at the operation and the geometry of the square holes. The experiments show that to machine a square hole, the controllers must be able to control a rotating axis itself, beyond to synchronize three axis. The critical to this kind of operation is the speed developed by the machine, being the most significant factor, the time the controller needs to process the block of programming, independently the activation of resources for high speed, linear or circular interpolations. It was verified than as larger the amount of points to compose the trajectory of the center of tool, better will be the geometry of the hole. Thus, the CNC machine tools in operation in the industry are able to machine the non-cylindrical drilling in a way very closely the cylindrical drilling as the time of machining and the fixing system of the tool and parts, requiring a programming that synchronizes the main spindle installed in any machine tool
Mestrado
Materiais e Processos de Fabricação
Mestre em Engenharia Mecânica
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Aasa, Johan. "Linear-Quadratic Regulation of ComputerRoom Air Conditioners." Thesis, Luleå tekniska universitet, Institutionen för system- och rymdteknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-71031.
Анотація:
Data centers operations are notoriously energy-hungry, with the computing and cooling infrastructures drawing comparable amount of electrical power to operate. A direction to improve their efciency is to optimizethe cooling, in the sense of implementing cooling infrastructures controlschemes that avoid performing over-cooling of the servers.Towards this direction, this work investigates minimum cost linearquadratic control strategies for the problem of managing air cooled datacenters. We derive a physical and a black box model for a general datacenter, identify this model from real data, and then derive, present andtest in the eld a model based Linear-Quadratic Regulator (LQR) strategy that sets the optimal coolant temperature for each individual coolingunit. To validate the approach we compare the eld tests from the LQR strategy against classical Proportional-Integral-Derivative (PID) controlstrategies, and show through our experiments that it is possible to reducethe energy consumption with respect to the existing practices by severalpoints percent without harming the servers within the data center fromthermal perspectives.
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Axehill, Daniel. "Integer quadratic programming for control and communcation /." Linköping : Department of Electrical Engineering, Linköping University, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-10642.
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Patek, Stephen D. (Stephen David). "Robust H[infinity] control via quadratic stabilization." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/12276.
Анотація:
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1994.On t.p., "[infinity]" appears subscript, as the mathematical symbol.
Includes bibliographical references (leaves 126-129).
by Stephen David Patek.
M.S.
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Axehill, Daniel. "Integer Quadratic Programming for Control and Communication." Doctoral thesis, Linköpings universitet, Reglerteknik, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-10642.
Анотація:
The main topic of this thesis is integer quadratic programming with applications to problems arising in the areas of automatic control and communication. One of the most widespread modern control methods is Model Predictive Control (MPC). In each sampling time, MPC requires the solution of a Quadratic Programming (QP) problem. To be able to use MPC for large systems, and at high sampling rates, optimization routines tailored for MPC are used. In recent years, the range of application of MPC has been extended to so-called hybrid systems. Hybrid systems are systems where continuous dynamics interact with logic. When this extension is made, binary variables are introduced in the problem. As a consequence, the QP problem has to be replaced by a far more challenging Mixed Integer Quadratic Programming (MIQP) problem, which is known to have a computational complexity which grows exponentially in the number of binary optimization variables. In modern communication systems, multiple users share a so-called multi-access channel. To estimate the information originally sent, a maximum likelihood problem involving binary variables can be solved. The process of simultaneously estimating the information sent by multiple users is called Multiuser Detection (MUD). In this thesis, the problem to efficiently solve MIQP problems originating from MPC and MUD is addressed. Four different algorithms are presented. First, a polynomial complexity preprocessing algorithm for binary quadratic programming problems is presented. By using the algorithm, some, or all, binary variables can be computed efficiently already in the preprocessing phase. In numerical experiments, the algorithm is applied to unconstrained MPC problems with a mixture of real valued and binary valued control signals, and the result shows that the performance gain can be significant compared to solving the problem using branch and bound. The preprocessing algorithm has also been applied to the MUD problem, where simulations have shown that the bit error rate can be significantly reduced compared to using common suboptimal algorithms. Second, an MIQP algorithm tailored for MPC is presented. The algorithm uses a branch and bound method where the relaxed node problems are solved by a dual active set QP algorithm. In this QP algorithm, the KKT systems are solved using Riccati recursions in order to decrease the computational complexity. Simulation results show that both the proposed QP solver and MIQP solver have lower computational complexity compared to corresponding generic solvers. Third, the dual active set QP algorithm is enhanced using ideas from gradient projection methods. The performance of this enhanced algorithm is shown to be comparable with the existing commercial state-of-the-art QP solver \cplex for some random linear MPC problems. Fourth, an algorithm for efficient computation of the search directions in an SDP solver for a proposed alternative SDP relaxation applicable to MPC problems with binary control signals is presented. The SDP relaxation considered has the potential to give a tighter lower bound on the optimal objective function value compared to the QP relaxation that is traditionally used in branch and bound for these problems, and its computational performance is better than the ordinary SDP relaxation for the problem. Furthermore, the tightness of the different relaxations is investigated both theoretically and in numerical experiments.This material is posted here with permission of the IEEE. Such permission of the IEEE does not in any way imply IEEE endorsement of any of the Linköping University's products or services. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to pubs-permissions@ieee.org. By choosing to view this material, you agree to all provisions of the copyright laws protecting it.
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Maciel, Allan James Ferreira. "CONVERGÊNCIA DO ESTIMADOR RLS PARA ALGORITMOS DE PROGRAMAÇÃO DINÂMICA HEURÍSTICA." Universidade Federal do Maranhão, 2012. http://tedebc.ufma.br:8080/jspui/handle/tede/494.
Анотація:
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Previous issue date: 2012-09-28Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
The union of methodologies for optimal control and dynamics programming has stimulated the development of algorithms for realization of discrete control systems of the type linear quadratic regulator (DLQR). The methodology is based on reinforcement learning methods based on temporal differences and approximate dynamic programming. The proposed method combines the approach of the value function by method RLS (recursive least squares) and approximate policy iteration schemes heuristic dynamic programming (HDP). The approach is directed to the assessment of convergence of the solution DLQR and the heuristic weighting matrices and of the utility function associated with DLQR. The investigation of convergence properties related to consistency, persistent excitation and polarization of the RLS estimator is performed. The methodology involved in a project achievements online DLQR controllers and is evaluated in a fourth order multivariable dynamic system.
A união das metodologias de controle ótimo e de programação dinâmica tem impulsionado o desenvolvimento de algoritmos para realizações de sistemas de controle discreto do tipo regulador linear quadrático (DLQR). A metodologia utilizada neste trabalho é fundamentada sobre métodos de aprendizagem por reforço baseados em diferenças temporais e programação dinâmica aproximada. O método proposto combina a aproximação da função valor através do método RLS (mínimos quadrados recursivos) e iteração de política aproximada em esquemas de programação dinâmica heurística (HDP). A abordagem é orientada para a avaliação da convergência da solução DLQR e para a sintonia heurística das matrizes de ponderação e da função de utilidade associada ao DLQR. É realizada a investigação das propriedades de convergência relacionadas à consistência, excitação persistente e polarização do estimador RLS. A metodologia contempla realizações de projetos de forma online de controladores DLQR e é avaliada em um sistema dinâmico multivariável de quarta ordem.
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Liang, Kuo-Yun. "Linear Quadratic Control for Heavy Duty Vehicle Platooning." Thesis, KTH, Reglerteknik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-55913.
Анотація:
Scania CV AB has estimated that the fuel consumption constitutes 30% of the operational costs of a heavy duty vehicle. With the increasing oil price, reducing the fuel consumption becomes highly profitable. A mitigation to the high fuel consumption is to form a platoon. By introducing vehicle platooning, the fuel consumption is reduced for the following vehicles. The fuel consumption is reduced due to the slipstream effect, which is an atmospheric drag reduction that occurs behind a traveling vehicle. Therefore, by driving the vehicles at a close intermediate distance, the overall resistive force is reduced. First a study of robustness, of a finite long platoon based upon the string stability criteria, is done. The main focus of this thesis is to find a centralized control law for a finite platoon, which considers the air drag reduction. A LQR and a LQT controller are presented with respect to a given information structure for a three-vehicle platoon. Simulation results show an energy reduction of up to 11.4% for the second vehicle and up to 13.1% for the third vehicle, when driving 80 km/h in a platoon on a highway between Södertälje and Norrköping with a time headway of 0.25 s.
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Ghoneim, Youssef Ahmed. "Indirect adaptive control using the linear quadratic solution." Thesis, McGill University, 1985. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=72028.
Анотація:
This thesis studies the indirect adaptive control for discrete linear time invariant systems. The adaptive control strategy is based on the linear quadratic regulator that places the closed loop poles such that an infinite stage quadratic cost function is minimized. The plant parameters are identified recursively using a projection algorithm.First, we study the effect of the model over-parametrization. For this purpose, we introduce an algorithm to generate the controller parameters recursively. This asymptotic reformulation is shown to overcome situations in which the pole-zero cancellation is a limit point of the identification algorithm. We also show that the algorithm will generate a unique control sequence that converges asymptotically to the solution of the Diophantine (pole assignment) equation.
Next, we study the stability of the proposed adaptive scheme in both deterministic and stochastic cases. We show that the global stability of the resulting adaptive scheme is obtained with no implicit assumptions about parameter convergence or the nature of the external input. Then the global convergence of the adaptive algorithm is obtained if the external input is "persistently exciting". By convergence we mean that the adaptive control will converge to the optimal control of the system.
The performance of the adaptive algorithm in the presence of deterministic disturbances is also considered, where we show that the adaptive controller performs relatively well if the model order is high enough to include a description of the disturbances.
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Douglas, Joel S. (Joel Seth). "Linear quadratic control for systems with structured uncertainty." Thesis, Massachusetts Institute of Technology, 1991. http://hdl.handle.net/1721.1/35358.
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Uddin, Md Mosleh. "Active Vibration Control of Helicopter Rotor Blade by Using a Linear Quadratic Regulator." ScholarWorks@UNO, 2018. https://scholarworks.uno.edu/td/2499.
Анотація:
Active vibration control is a widely implemented method for the helicopter vibration control. Due to the significant progress in microelectronics, this technique outperforms the traditional passive control technique due to weight penalty and lack of adaptability for the changing flight conditions. In this thesis, an optimal controller is designed to attenuate the rotor blade vibration. The mathematical model of the triply coupled vibration of the rotating cantilever beam is used to develop the state-space model of an isolated rotor blade. The required natural frequencies are determined by the modified Galerkin method and only the principal aerodynamic forces acting on the structure are considered to obtain the elements of the input matrix. A linear quadratic regulator is designed to achieve the vibration reduction at the optimum level and the controller is tuned for the hovering and forward flight with different advance ratios.
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Silva, Cleiton Diniz Pereira da Silva e. "Controle ótimo de equações diferenciais estocásticas lineares excitadas por martingales quadrado integráveis." Instituto Tecnológico de Aeronáutica, 2008. http://www.bd.bibl.ita.br/tde_busca/arquivo.php?codArquivo=782.
Анотація:
Este trabalho trata do controle ótimo de sistemas descritos por Equações Diferenciais Estocásticas (EDE). Os resultados apresentados podem ser divididos em três partes. A primeira delas aborda um problema de controle ótimo não-linear sendo investigada a possibilidade de considerar como controles admissíveis processos adaptados à s-álgebra gerada pelo estado Xut . As hipóteses de um resultado disponível na literatura são relaxadas e estende-se à classe de problemas para os quais existe um subconjunto de processos de controle Ucl, tal que para todo u em Ucl,, Xut é igual à s-álgebra gerada pelo processo de Wiener Wt. Como conseqüência, mostra-se que, dado um e> 0, pode-se construir um controle em malha fechada que é e -ótimo na classe de controles limitados no L2 e adaptados à Wt. Na segunda parte, estuda-se o problema de otimização Linear Quadrático (LQ) de sistemas excitados aditivamente por martingales quadrado integráveis tanto contínuos quanto descontínuos. Dois casos principais são considerados: sistema sem saltos e com saltos Markovianos nos parâmetros. No primeiro caso, além do distúrbio aditivo considera-se casos de sistemas com distúrbios multiplicativos tanto de Wiener quanto de Poisson. Para os problemas com observações completas o controle ótimo é determinado explicitamente, dependendo da solução de uma equação de Riccati, e para problemas com observações parciais os resultados obtidos são interpretados como uma condição necessária para validade do princípio de equivalência à certeza. A principal contribuição nesta parte do trabalho é mostrar que o caso de sistemas excitados por martingale quadrado integráveis pode ser tratado de maneira similar ao caso clássico sendo apresentadas soluções explícitas. Na terceira parte, é abordado o problema de controle Linear Exponencial Quadrático Gaussiano (LEQG) de sistemas lineares excitados pelo processo de Wiener restrigindo-se os controles admissíveis a processos constantes por partes com observações restritas a apenas certos instantes de tempo fixados a priori. São analisados casos com observações sem ruído e observações ruidosas sendo mostrado que ambos os problemas podem ser estudados por métodos diretos.
17
Kikuchi, Davi Yoshinobu. "Sistema de controle servo visual de uma câmera pan-tilt com rastreamento de uma região de referência." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/3/3152/tde-27072007-163810/.
Анотація:
Uma câmera pan-tilt é capaz de se movimentar em torno de dois eixos de rotação (pan e tilt), permitindo que sua lente possa ser apontada para um ponto qualquer no espaço. Uma aplicação possível dessa câmera é mantê-la apontada para um determinado alvo em movimento, através de posicionamentos angulares pan e tilt adequados. Este trabalho apresenta uma técnica de controle servo visual, em que, inicialmente, as imagens capturadas pela câmera são utilizadas para determinar a posição do alvo. Em seguida, calculam-se as rotações necessárias para manter a projeção do alvo no centro da imagem, em um sistema em tempo real e malha fechada. A técnica de rastreamento visual desenvolvida se baseia em comparação de uma região de referência, utilizando a soma dos quadrados das diferenças (SSD) como critério de correspondência. Sobre essa técnica, é adicionada uma extensão baseada no princípio de estimação incremental e, em seguida, o algoritmo é mais uma vez modificado através do princípio de estimação em multiresolução. Para cada uma das três configurações, são realizados testes para comparar suas performances. O sistema é modelado através do princípio de fluxo óptico e dois controladores são apresentados para realimentar o sistema: um proporcional integral (PI) e um proporcional com estimação de perturbações externas através de um filtro de Kalman (LQG). Ambos são calculados utilizando um critério linear quadrático e os desempenhos deles também são analisados comparativamente.A pan-tilt camera can move around two rotational axes (pan and tilt), allowing its lens to be pointed to any point in space. A possible application of the camera is to keep it pointed to a certain moving target, through appropriate angular pan-tilt positioning. This work presents a visual servoing technique, which uses first the images captured by the camera to determinate the target position. Then the method calculates the proper rotations to keep the target position in image center, establishing a real-time and closed-loop system. The developed visual tracking technique is based on template region matching, and makes use of the sum of squared differences (SSD) as similarity criterion. An extension based on incremental estimation principle is added to the technique, and then the algorithm is modified again by multiresolution estimation method. Experimental results allow a performance comparison between the three configurations. The system is modeled through optical flow principle and this work presents two controllers to accomplish the system feedback: a proportional integral (PI) and a proportional with external disturbances estimation by a Kalman filter (LQG). Both are determined using a linear quadratic method and their performances are also analyzed comparatively.
18
Lidbäck, Christopher. "Linear Quadratic and PI Control of anElectrically Actuated Throttle." Thesis, KTH, Reglerteknik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-133583.
Анотація:
In diesel engines throttle valves are used for various purposes. One of these is to control the amount of air which is let into the cylinders. A precise amount of air is needed for optimal combustion, and for that reason a throttle is used to regulate air intake. As technology has advanced, it has become more common to control these throttles with electrical actuators as opposed to pneumatic ones as electric actuators are faster and more accurate. In this thesis, two methods to position control a brush-less direct current motor are proposed. One consists of a linear quadratic controller which is evaluated with simulations and one consists of a single PI-controller which is evaluated both with simulations and with experiments. The motor is controlled with three pulse width modulated signals generated with six transistors mounted on half-bridges. It is shown that good control performance can be achieved with both controllers.
19
Axehill, Daniel. "Applications of Integer Quadratic Programming in Control and Communication." Licentiate thesis, Linköping : Dept. of Electrical Engineering, Linköping University, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-5263.
20
Benner, Peter, Enrique S. Quintana-Ortí, and Gregorio Quintana-Ortí. "Solving Linear-Quadratic Optimal Control Problems on Parallel Computers." Universitätsbibliothek Chemnitz, 2006. http://nbn-resolving.de/urn:nbn:de:swb:ch1-200601704.
Анотація:
We discuss a parallel library of efficient algorithms for the solution of linear-quadratic optimal control problems involving largescale systems with state-space dimension up to $O(10^4)$. We survey the numerical algorithms underlying the implementation of the chosen optimal control methods. The approaches considered here are based on invariant and deflating subspace techniques, and avoid the explicit solution of the associated algebraic Riccati equations in case of possible ill-conditioning. Still, our algorithms can also optionally compute the Riccati solution. The major computational task of finding spectral projectors onto the required invariant or deflating subspaces is implemented using iterative schemes for the sign and disk functions. Experimental results report the numerical accuracy and the parallel performance of our approach on a cluster of Intel Itanium-2 processors.
21
Charikhi, Mourad. "Contrôle dynamique de calculs numériques d'intégrales multiples." Paris 6, 2005. http://www.theses.fr/2005PA066005.
22
Shen, Dan. "Nash strategies for dynamic noncooperative linear quadratic sequential games." Columbus, Ohio : Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1156434869.
23
Jerrelind, Esaias. "Linear Quadratic Control of a Marine Vehicle with Azimuth Propulsion." Thesis, Linköpings universitet, Reglerteknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-178007.
24
Caldeira, Fabrício Reis. "Design of an automatic landing system using linear quadratic tracker." Instituto Tecnológico de Aeronáutica, 2008. http://www.bd.bibl.ita.br/tde_busca/arquivo.php?codArquivo=725.
Анотація:
This work presents the application of the Linear Quadratic Tracker (LQT) for the automatic landing system of passenger transport airplanes. The design method to achieve an autoland flare law with improved performance and disturbance rejection is described. With this method the design is direct and more formal thus avoiding the somewhat time consuming and more ad-hoc design iterations currently practice in industry. Although the design technique has been used for a autoland system, the approach is general enough to be used in other control applications. The structure of a traditional flare controller used for transport airplane and the LQT flare controller are presented. The performance of the flare control law designed based on LQT is compared against the performance of a traditional flare control law. Simulation time histories and Monte Carlo simulation results are presented. The time histories simulations cover the nominal and the most adverse conditions anticipated during the operation of the autoland system. The results show that the LQT law provides a more accurate path control and better disturbance rejection. The Monte Carlo simulation was made according to the certification requirements of an autoland system. The results show that the LQT controller provides reduced touchdown dispersion for the sink rate and distance at touchdown. The automatic landing system using LQT complies easily with the certification requirements, whereas the traditional system based on the classical design of autopilot inner loop/outer loop meets the certification requirements with smaller margins.
25
Benner, Peter, and Jens Saak. "Linear-Quadratic Regulator Design for Optimal Cooling of Steel Profiles." Universitätsbibliothek Chemnitz, 2006. http://nbn-resolving.de/urn:nbn:de:swb:ch1-200601597.
Анотація:
We present a linear-quadratic regulator (LQR) design for a heat transfer model describing the cooling process of steel profiles in a rolling mill. Primarily we consider a feedback control approach for a linearization of the nonlinear model given there, but we will also present first ideas how to use local (in time) linearizations to treat the nonlinear equation with a regulator approach. Numerical results based on a spatial finite element discretization and a numerical algorithm for solving large-scale algebraic Riccati equations are presented both for the linear and nonlinear models.
26
Fang, Yong Jie. "Dynamic and transient system control using fast acting quadrature boosters." Thesis, Imperial College London, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.244084.
27
Khalid, Muhammad Salman. "Linear Quadratic Regulator and Receding Horizon Control for Constrained Systems." Thesis, University of Sheffield, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.515489.
28
Stibbe, Hilke Isabell [Verfasser], and Ekaterina [Akademischer Betreuer] Kostina. "Special Bilevel Quadratic Problems for Construction of Worst-Case Feedback Control in Linear-Quadratic Optimal Control Problems under Uncertainties / Hilke Isabell Stibbe ; Betreuer: Ekaterina Kostina." Marburg : Philipps-Universität Marburg, 2019. http://d-nb.info/1202110509/34.
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Furtado, Guilherme Phillips. "Formulation of impedance control strategy as an optimal control problem." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/3/3152/tde-05022019-153033/.
Анотація:
A formulation of impedance control for redundant manipulators is developed as a particular case of an optimal control problem. This formulation allows the planning and design of an impedance controller that benets from the stability and eficiency of an optimal controller. Moreover, to circumvent the high computational costs of computing an optimal controller, a sub-optimal feedback controller based on the state-dependent Ricatti equation (SDRE) approach is developed. This approach is then compared with the quadratic programming (QP) control formulation, commonly used to resolve redundancy of robotic manipulators. Numerical simulations of a redundant planar 4-DOF serial link manipulator show that the SDRE control formulation offers superior performance over the control strategy based QP, in terms of stability, performance and required control effort.Uma formulação do controle de impedância para manipuladores redundantes é desenvolvida como um caso particular de um problema de controle ótimo. Essa formulação permite o planejamento e projeto de um controlador de impedância que se beneficia da estabilidade e eficiência de um controlador ótimo. Para evitar lidar com os elevados custos computacionais de se computar um controlador ótimo, um controlador em malha fechada sub-ótimo, baseado na abordagem das equações de Ricatti dependentes de estado (SDRE), é desenvolvido. Essa abordagem é comparada com a formulação de um controlador baseado em programação quadrática (QP), usualmente utilizado para resolver problemas de redundância em manipuladores robóticos. Simulações numéricas de um manipulador serial plano de quatro graus de liberdade mostram que o controlador baseado em SDRE oferece performance superior em relação a um controlador baseado em programação quadrática, em termos de estabilidade, performance e esforço de controle requerido do atuador.
30
Rieber, Jochen M. "Control of uncertain systems with l 1 and quadratic performance objectives." [S.l. : s.n.], 2007. http://nbn-resolving.de/urn:nbn:de:bsz:93-opus-31056.
31
Pimenta, Karla Boaventura. "Controle de juntas roboticas usando controlador preditivo generalizado adaptativo direto." [s.n.], 2003. http://repositorio.unicamp.br/jspui/handle/REPOSIP/265347.
Анотація:
Orentadores: João Mauricio Rosario, Didier DumurTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica
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Doutorado
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Govindaraj, Thavamani. "Optimal Control of a Stochastic Heat Equation with Control and Noise on the Boundary." Thesis, Linnéuniversitetet, Institutionen för matematik (MA), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-76037.
Анотація:
In this thesis, we give a mathematical background of solving a linear quadratic control problem for the heat equation, which involves noise on the boundary, in a concise way. We use the semigroup approach for the solvability of the problem. To obtain optimal controls, we use optimization techniques for convex functionals. Finally we give a feedback form for the optimal control. In order to enhance understanding of linear quadratic problem, we first present the methods in deterministic cases and then extend to noisy systems.
33
Mackenzie, Neil C. "The independent quadratic optimisation algorithm for the active control of noise and vibration /." Title page, contents and abstract only, 1996. http://web4.library.adelaide.edu.au/theses/09PH/09phm15742.pdf.
34
Orazi, Daniele. "Model Predictive Control for linear uncertain systems using Pointwise Integral Quadratic Constraints." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2022.
Анотація:
When controlling safety-critical systems with uncertain components, constraint satisfaction is not only vital but also a major challenge. Model predictive control (MPC) is a common solution to satisfy strict state and input constraints. However, on its own it is not able to deal with uncertainties. Hence, it is necessary to robustify this controller. With this aim, recently contributions have been provided on a tube-based robust MPC scheme for state and input constrained linear systems subject to dynamic uncertainties described by ρ-hard integral quadratic constraints (IQCs). Nonetheless, often ρ-hard IQCs description is too general while uncertainties can be more specifically described by pointwise IQCs. This work is intended to exploit this specific information to improve the existing approach. In particular, the original work shows that the model error between the real uncertain system and the nominal prediction model is bounded by an exponentially stable scalar system. In our work we prove that exploiting the additional information on the uncertainty we can obtain a tighter and simpler bound which results in a set of improvements. In a numerical example, we show these improvements that our result guarantees in terms of computation and in terms of effort needed by the MPC controller.
35
Homsi, Saed Al. "Online generation of time- optimal trajectories for industrial robots in dynamic environments." Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAT027/document.
Анотація:
Nous observons ces dernières années un besoin grandissant dans l’industrie pour des robots capables d’interagir et de coopérer dans des environnements confinés. Cependant, aujourd’hui encore, la définition de trajectoires sûres pour les robots industriels doit être faite manuellement par l’utilisateur et le logiciel ne dispose que de peu d’autonomie pour réagir aux modifications de l’environnement. Cette thèse vise à produire une structure logicielle innovante pour gérer l’évitement d’obstacles en temps réel pour des robots manipulateurs évoluant dans des environnements dynamiques. Nous avons développé pour cela un algorithme temps réel de génération de trajectoires qui supprime de façon automatique l’étape fastidieuse de définition d’une trajectoire sûre pour le robot.La valeur ajoutée de cette thèse réside dans le fait que nous intégrons le problème de contrôle optimal dans le concept de hiérarchie de tâches pour résoudre un problème d’optimisation non-linéaire efficacement et en temps réel sur un système embarqué aux ressources limitées. Notre approche utilise une commande prédictive (MPC) qui non seulement améliore la réactivité de notre système mais présente aussi l’avantage de pouvoir produire une bonne approximation linéaire des contraintes d’évitement de collision. La stratégie de contrôle présentée dans cette thèse a été validée à l’aide de plusieurs expérimentations en simulations et sur systèmes réels. Les résultats démontrent l’efficacité, la réactivité et la robustesse de cette nouvelle structure de contrôle lorsqu’elle est utilisée dans des environnements dynamiquesIn the field of industrial robots, there is a growing need for having cooperative robots that interact with each other and share work spaces. Currently, industrial robotic systems still rely on hard coded motions with limited ability to react autonomously to dynamic changes in the environment. This thesis focuses on providing a novel framework to deal with real-time collision avoidance for robots performing tasks in a dynamic environment. We develop a reactive trajectory generation algorithm that reacts in real time, removes the fastidious optimization process which is traditionally executed by hand by handling it automatically, and provides a practical way of generating locally time optimal solutions.The novelty in this thesis is in the way we integrate the proposed time optimality problem in a task priority framework to solve a nonlinear optimization problem efficiently in real time using an embedded system with limited resources. Our approach is applied in a Model Predictive Control (MPC) setting, which not only improves reactivity of the system but presents a possibility to obtain accurate local linear approximations of the collision avoidance constraint. The control strategies presented in this thesis have been validated through various simulations and real-world robot experiments. The results demonstrate the effectiveness of the new control structure and its reactivity and robustness when working in dynamic environments
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Ferreira, Ernesto Franklin Marçal. "Melhorias de estabilidade numérica e custo computacional de aproximadores de funções valor de estado baseados em estimadores RLS para projeto online de sistemas de controle HDP-DLQR." Universidade Federal do Maranhão, 2016. http://tedebc.ufma.br:8080/jspui/handle/tede/1687.
Анотація:
Submitted by Rosivalda Pereira (mrs.pereira@ufma.br) on 2017-06-23T20:34:27Z
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The development and the numerical stability analysis of a new adaptive critic algorithm to approximate the state-value function for online discrete linear quadratic regulator (DLQR) optimal control system design based on heuristic dynamic programming (HDP) are presented in this work. The proposed algorithm makes use of unitary transformations and QR decomposition methods to improve the online learning e-ciency in the critic network through the recursive least-squares (RLS) approach. The developed learning strategy provides computational performance improvements in terms of numerical stability and computational cost which aim at making possible the implementations in real time of optimal control design methodology based upon actor-critic reinforcement learning paradigms. The convergence behavior and numerical stability of the proposed online algorithm, called RLSµ-QR-HDP-DLQR, are evaluated by computational simulations in three Multiple-Input and Multiple-Output (MIMO) models, that represent the automatic pilot of an F-16 aircraft of third order, a fourth order RLC circuit with two input voltages and two controllable voltage levels, and a doubly-fed induction generator with six inputs and six outputs for wind energy conversion systems.
Neste trabalho, apresenta-se o desenvolvimento e a análise da estabilidade numérica de um novo algoritmo crítico adaptativo para aproximar a função valor de estado para o projeto do sistema de controle ótimo online, utilizando o regulador linear quadrático discreto (DLQR), com base em programação dinâmica heurística (HDP). O algoritmo proposto faz uso de transformações unitárias e métodos de decomposição QR para melhorar a e-ciência da aprendizagem online na rede crítica por meio da abordagem dos mínimos quadrados recursivos (RLS). A estratégia de aprendizagem desenvolvida fornece melhorias no desempenho computacional em termos de estabilidade numérica e custo computacional, que visam tornar possíveis as implementações em tempo real da metodologia do projeto de controle ótimo com base em paradigmas de aprendizado por reforço ator-crítico. O comportamento de convergência e estabilidade numérica do algoritmo online proposto, denominado RLSµ-QR-HDP-DLQR, são avaliados por meio de simulações computacionais em três modelos Múltiplas-Entradas e Múltiplas-Saídas (MIMO), que representam o piloto automático de uma aeronave F-16 de terceira ordem, um circuito de quarta ordem RLC com duas tensões de entrada e dois níveis de tensão controláveis, e um gerador de indução duplamente alimentados com seis entradas e seis saídas para sistemas de conversão de energia eólica.
37
McClusky, Jacqueline R. "Active damping of vibrations on space station freedom using Linear Quadratic Gaussian control and H_x001B_p00_x001B_s control." Thesis, Monterey, California. Naval Postgraduate School, 1991. http://hdl.handle.net/10945/26344.
38
Chen, Xiao. "Fuel optimal powertrain control of heavy-duty vehicle based on model predictive control and quadratic programming." Thesis, KTH, Reglerteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-217527.
Анотація:
The freight transport has a fundamental role in the world’s economic development.Due to the flexibility of heavy-duty vehicles, a large part of freighttransport is carried out inland. Although the use of heavy-duty vehicles contributesto the economic growth, the increased fuel consumption and globalgreenhouse gas emission that come with it constantly challenge the transportationsector to adapt and develop more fuel-efficient methods to reduce suchside effects while fulfilling the transportation requirements.This thesis considers fuel-optimal highway driving for heavy-duty vehicles.A model predictive control algorithm for minimizing fuel consumptionwhile satisfying constraints on desired speed is developed and evaluated. Thecontroller uses the available topography information of the road ahead of thevehicle in order to achieve an efficient vehicle control while satisfying a certaintrip time requirement. Under the assumption of fixed gear during the drivemission, the actual nonlinear problem is re-formulated as a real-time optimalcontrol problem based on MPC theory with a quadratic cost function and linearconstraints at each receding horizon of the drive mission. The QP problem isthen solved online and the resulting first control action is applied to the vehiclefor forward movement.The feasibility to implement such an algorithm on a control unit with limitedcomputational power is investigated and shown to be possible. Both therequirement of low computational complexity and low memory occupation arefulfilled by the tailored quadratic programming algorithm developed in thisthesis. The algorithm is fast enough to provide a solution within each samplinginterval.The overall control algorithm is implemented on a G5 control unit andtested in real life with a Scania truck during highway driving test. The resultsfrom both the real implementation and extensive simulations indicate that themethod provides a fuel-efficient vehicle behavior and is competitive with a rulebasedcontroller.Transport av gods har en grundläggande roll i världens ekonomiska utveckling.På grund av flexibiliteten hos tunga fordon, utförs en stor del av allgodstransport med hjälp av dem. Trots att användning av tunga fordon bidrartill ekonomisk tillväxt, utgör bränsleförbrukning tillsammans med den ökadeutsläpp av växthusgas en utmaning för transportföretag att anpassa och utvecklamer bränslesnål och miljövänligare transportteknologi för tunga fordon.I detta examensarbete fokuserar man på körningen av lastbil på motorvägar.En bränsle optimal förutsägande styralgoritm är utvecklad och utvärderad.Algoritmen utnyttjar framför allt topografi information om vägen framför fordonetså att den kan planera körningen på ett bränslesparande sätt samtidigtsom den uppfyller ett visst tidskrav. Med antagande om konstant växel underkörningen, formuleras ett optimal styrningsproblem baserat på ett MPC ramverkmed kvadratisk målfunktion och linjära bivillkor. Den slutliga kvadratiskoptimeringsproblemet för varje styrhorisont är löst med hjälp av en för ändamåletframtagen QP-algoritm.Möjligheten att implementera en sådan algoritm på en inbyggd styrenhetär undersökt och veriferad. Både krav på låg beräkningskomplexitet och lågminnes användning är uppfylls av den MPC-anpassade QP-lösare som utvecklatsi detta examensarbete.Den slutliga styralgoritmen testades i verkligheten med en Scania lastbilpå motorväg. Resultat från både provkörning och simulering visar att metodenger en bränsleeffektiv körstrategi, som kan spara bränsle jämfört med en regelbaseradprediktiv farthållaren.
39
Johansson, Marcus. "Online Whole-Body Control using Hierarchical Quadratic Programming : Implementation and Evaluation of the HiQP Control Framework." Thesis, Linköpings universitet, Artificiell intelligens och integrerade datorsystem, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-133224.
Анотація:
The application of local optimal control is a promising paradigm for manipulative robot motion generation.In practice this involves instantaneous formulations of convex optimization problems depending on the current joint configuration of the robot and the environment.To be effective, however, constraints have to be carefully constructed as this kind of motion generation approach has a trade-off of completeness.Local optimal solvers, which are greedy in a temporal sense, have proven to be significantly more effective computationally than classical grid-based or sampling-based planning approaches. In this thesis we investigate how a local optimal control approach, namely the task function approach, can be implemented to grant high usability, extendibility and effectivity.This has resulted in the HiQP control framework, which is compatible with ROS, written in C++.The framework supports geometric primitives to aid in task customization by the user.It is also modular as to what communication system it is being used with, and to what optimization library it uses for finding optimal controls. We have evaluated the software quality of the framework according to common quantitative methods found in the literature.We have also evaluated an approach to perform tasks using minimal jerk motion generation with promising results.The framework also provides simple translation and rotation tasks based on six rudimentary geometric primitives.Also, task definitions for specific joint position setting, and velocity limitations were implemented.
40
Tröltzsch, F. "Lipschitz stability of solutions to linear-quadratic parabolic control problems with respect to perturbations." Universitätsbibliothek Chemnitz, 1998. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-199801229.
Анотація:
We consider a class of control problems governed by a linear parabolic initial-boundary
value problem with linear-quadratic objective and pointwise constraints on the control.
The control system contains different types of perturbations. They appear in the
linear part of the objective functional, in the right hand side of the equation,
in its boundary condition, and in the initial value. Making use of parabolic regularity
in the whole scale of $L^p$ the known Lipschitz stability in the $L^2$-norm
is improved to the supremum-norm.
41
Howe, Sei. "Upper and lower bounds for singularly perturbed linear quadratic optimal control problems." Thesis, Imperial College London, 2017. http://hdl.handle.net/10044/1/54758.
Анотація:
The question of how to optimally control a large scale system is widely considered to be difficult to solve due to the size of the problem. This difficulty is further compounded when a system exhibits a two time-scale structure where some components evolve slowly and others evolve quickly. When this occurs, the optimal control problem is regarded as singularly perturbed with a perturbation parameter epsilon representing the ratio of the slow time-scale to the fast time-scale. As epsilon goes to zero, the system becomes stiff resulting in a computationally intractable problem. In this thesis, we propose an analytic method for constructing bounds on the minimum cost of a singularly perturbed, linear-quadratic optimal control problem that hold for any arbitrary value of epsilon.
42
Fry, Jedediah Micah. "On Integral Quadratic Constraint Theory and Robust Control of Unmanned Aircraft Systems." Diss., Virginia Tech, 2019. http://hdl.handle.net/10919/102615.
Анотація:
This dissertation advances tools for the certification of unmanned aircraft system (UAS) flight controllers. We develop two thrusts to this goal: (1) the validation and improvement of an uncertain UAS framework based on integral quadratic constraint (IQC) theory and (2) the development of novel IQC theorems which allow the analysis of uncertain systems having time-varying characteristics.
Pertaining to the first thrust, this work improves and implements an IQC-based robustness analysis framework for UAS. The approach models the UAS using a linear fractional transformation on uncertainties and conducts robustness analysis on the uncertain system via IQC theory. By expressing the set of desired UAS flight paths with an uncertainty, the framework enables analysis of the uncertain UAS flying about any level path whose radius of curvature is bounded. To demonstrate the versatility of this technique, we use IQC analysis to tune trajectory-tracking and path-following controllers designed via H2 or H-infinity synthesis methods. IQC analysis is also used to tune path-following PID controllers. By employing a non-deterministic simulation environment and conducting numerous flight tests, we demonstrate the capability of the framework in predicting loss of control, comparing the robustness of different controllers, and tuning controllers. Finally, this work demonstrates that signal IQCs have an important role in obtaining IQC analysis results which are less conservative and more consistent with observations from flight test data.
With regards to the second thrust, we prove a novel theorem which enables robustness analysis of uncertain systems where the nominal plant and the IQC multiplier are linear time-varying systems and the nominal plant may have a non-zero initial condition. When the nominal plant and the IQC multiplier are eventually periodic, robustness analysis can be accomplished by solving a finite-dimensional semidefinite program. Time-varying IQC multipliers are beneficial in analysis because they provide the possibility of reducing conservatism and are capable of expressing uncertainties that have unique time-domain characteristics. A number of time-varying IQC multipliers are introduced to better describe such uncertainties. The utility of this theorem is demonstrated with various examples, including one which produces bounds on the UAS position after an aggressive Split-S maneuver.Doctor of Philosophy
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Blomberg, Magnus. "High Bandwidth Control of a Small Aerial Vehicle." Thesis, Linköpings universitet, Reglerteknik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-119622.
Анотація:
Small aerial vehicles such as quad-rotors have been widely used commercially, for research and for hobby for the last decade with use still growing. The high interest is mainly due to the vehicles being small, simple, cheap and versatile. Among rigid body dynamics fast dynamics exist cohering to motors and other fast actuators. A linear quadratic control design technique is here investigated. The design technique suggests that the linear quadratic controller can be designed with penalties on the slow states only. The fast dynamics are modeled but the states are not penalised in the linear quadratic design. The design technique is here applied and evaluated. The results show that this in several cases is a suitable design technique for linear quadratic control design. MATLAB and Simulink have been widely used for design and implementation of control systems. With additional toolboxes these control systems can be compiled to and run on remote computers. Small, lightweight computers with high computational capacity are now easily accessible. In this thesis an avionics solution based on a small, powerful computer is presented. Simulink models can be compiled and transferred to the computer from the Simulink environment. The result is a user friendly way of rapid prototyping and evaluation of control systems.
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Ndounkeu, Ludovic Tangpi. "Optimal cross hedging of Insurance derivatives using quadratic BSDEs." Thesis, Stellenbosch : Stellenbosch University, 2011. http://hdl.handle.net/10019.1/17950.
Анотація:
Thesis (MSc)--Stellenbosch University, 2011.ENGLISH ABSTRACT: We consider the utility portfolio optimization problem of an investor whose activities are influenced by an exogenous financial risk (like bad weather or energy shortage) in an incomplete financial market. We work with a fairly general non-Markovian model, allowing stochastic correlations between the underlying assets. This important problem in finance and insurance is tackled by means of backward stochastic differential equations (BSDEs), which have been shown to be powerful tools in stochastic control. To lay stress on the importance and the omnipresence of BSDEs in stochastic control, we present three methods to transform the control problem into a BSDEs. Namely, the martingale optimality principle introduced by Davis, the martingale representation and a method based on Itô-Ventzell’s formula. These approaches enable us to work with portfolio constraints described by closed, not necessarily convex sets and to get around the classical duality theory of convex analysis. The solution of the optimization problem can then be simply read from the solution of the BSDE. An interesting feature of each of the different approaches is that the generator of the BSDE characterizing the control problem has a quadratic growth and depends on the form of the set of constraints. We review some recent advances on the theory of quadratic BSDEs and its applications. There is no general existence result for multidimensional quadratic BSDEs. In the one-dimensional case, existence and uniqueness strongly depend on the form of the terminal condition. Other topics of investigation are measure solutions of BSDEs, notably measure solutions of BSDE with jumps and numerical approximations. We extend the equivalence result of Ankirchner et al. (2009) between existence of classical solutions and existence of measure solutions to the case of BSDEs driven by a Poisson process with a bounded terminal condition. We obtain a numerical scheme to approximate measure solutions. In fact, the existing self-contained construction of measure solutions gives rise to a numerical scheme for some classes of Lipschitz BSDEs. Two numerical schemes for quadratic BSDEs introduced in Imkeller et al. (2010) and based, respectively, on the Cole-Hopf transformation and the truncation procedure are implemented and the results are compared. Keywords: BSDE, quadratic growth, measure solutions, martingale theory, numerical scheme, indifference pricing and hedging, non-tradable underlying, defaultable claim, utility maximization.
AFRIKAANSE OPSOMMING: Ons beskou die nuts portefeulje optimalisering probleem van ’n belegger wat se aktiwiteite beïnvloed word deur ’n eksterne finansiele risiko (soos onweer of ’n energie tekort) in ’n onvolledige finansiële mark. Ons werk met ’n redelik algemene nie-Markoviaanse model, wat stogastiese korrelasies tussen die onderliggende bates toelaat. Hierdie belangrike probleem in finansies en versekering is aangepak deur middel van terugwaartse stogastiese differensiaalvergelykings (TSDEs), wat blyk om ’n onderskeidende metode in stogastiese beheer te wees. Om klem te lê op die belangrikheid en alomteenwoordigheid van TSDEs in stogastiese beheer, bespreek ons drie metodes om die beheer probleem te transformeer na ’n TSDE. Naamlik, die martingale optimaliteits beginsel van Davis, die martingale voorstelling en ’n metode wat gebaseer is op ’n formule van Itô-Ventzell. Hierdie benaderings stel ons in staat om te werk met portefeulje beperkinge wat beskryf word deur geslote, nie noodwendig konvekse versamelings, en die klassieke dualiteit teorie van konvekse analise te oorkom. Die oplossing van die optimaliserings probleem kan dan bloot afgelees word van die oplossing van die TSDE. ’n Interessante kenmerk van elkeen van die verskillende benaderings is dat die voortbringer van die TSDE wat die beheer probleem beshryf, kwadratiese groei en afhanglik is van die vorm van die versameling beperkings. Ons herlei ’n paar onlangse vooruitgange in die teorie van kwadratiese TSDEs en gepaartgaande toepassings. Daar is geen algemene bestaanstelling vir multidimensionele kwadratiese TSDEs nie. In die een-dimensionele geval is bestaan ââen uniekheid sterk afhanklik van die vorm van die terminale voorwaardes. Ander ondersoek onderwerpe is maatoplossings van TSDEs, veral maatoplossings van TSDEs met spronge en numeriese benaderings. Ons brei uit op die ekwivalensie resultate van Ankirchner et al. (2009) tussen die bestaan van klassieke oplossings en die bestaan van maatoplossings vir die geval van TSDEs wat gedryf word deur ’n Poisson proses met begrensde terminale voorwaardes. Ons verkry ’n numeriese skema om oplossings te benader. Trouens, die bestaande self-vervatte konstruksie van maatoplossings gee aanleiding tot ’n numeriese skema vir sekere klasse van Lipschitz TSDEs. Twee numeriese skemas vir kwadratiese TSDEs, bekendgestel in Imkeller et al. (2010), en gebaseer is, onderskeidelik, op die Cole-Hopf transformasie en die afknot proses is geïmplementeer en die resultate word vergelyk.
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Pereira, Fernando da Cruz. "Sensor óptico de alta tensão com chaveamento de quadratura e realimentado por controle de fase." Universidade Estadual Paulista (UNESP), 2018. http://hdl.handle.net/11449/153700.
Анотація:
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Os transformadores de potencial baseados em tecnologia óptica têm sido desenvolvidos com a finalidade de melhorar o desempenho na proteção e medição nos sistemas elétricos de potência. Estes transformadores de potencial podem ser projetados em torno dos moduladores eletro-ópticos de amplitude que, por sua vez, são baseados no efeito Pockels em cristal como o Niobato de Lítio. A expressão geral da transmissão (razão entre o retardo de fase e a tensão aplicada) de um modulador eletro-óptico de intensidades é idêntica à expressão do sinal de saída de um interferômetro de dois feixes. Através de processamento eletrônico de dois sinais interferométricos de saída, com fase relativa de 90o entre si, consegue-se demodular o sinal, independentemente das derivas ambientais. Esses interferômetros, chamados de interferômetros de quadratura, são amplamente utilizados em laboratórios de metrologia. Assim, em 2014, um método de detecção interferométrica de fase óptica foi desenvolvido no Laboratório de Optoeletrônica (LOE) da FEIS-UNESP, constituindo uma versão melhorada da técnica de phase-unwrapping. Este método é imune ao fenômeno de desvanecimento, consegue medir o tempo de atraso entre o estímulo e a resposta, tem ampla faixa dinâmica, reconstrói a forma de onda do sinal de modulação sem a necessidade de aplicação de filtros à saída interferométrica, possuindo, ainda, a capacidade de demodular sinais com formas de ondas não periódicas. Beneficiando-se dessas informações, promoveu-se a adaptação do método a um sensor óptico de altas tensões em configuração de quadratura de sinais. Desta forma, a presente pesquisa aborda o estudo e o desenvolvimento de um sensor óptico de alta tensão com chaveamento de quadratura, baseado em célula Pockels, dando continuidade às pesquisas em desenvolvimento no LOE, de um sistema de sensoriamento eletro-óptico de alta tensão. O sensor de alta tensão com chaveamento de quadratura e realimentado por controle de fase, foi implementado e submetido a testes com aplicação de tensões entre 200 V e 8,4 kV (de pico) em 60 Hz, apresentado excelente linearidade na faixa de interesse e boa precisão na medição do conteúdo harmônico dos sinais. Tais resultados evidenciam o potencial do sistema para operar na análise da qualidade de energia elétrica em sistemas da classe de 13,8 kV.
Optical technology-based potential transformers have been developed to improve performance in protection and measurement in electrical power systems. These potential transformers can be designed around amplitude electro-optical modulators which, in turn, are based on the crystal Pockels effect such as Lithium Niobate. The general expression of the transmission (ratio between phase delay and applied voltage) of an electro-optical modulator of intensities is identical to the expression of the output signal of a two-beam interferometer. By electronic processing of two interferometric output signals, with relative phase of 90o between each other, the signal can be demodulated, irrespective of the environmental drift. These interferometers, called quadrature interferometers, are widely used in metrology laboratories. Thus, in 2014, an optical phase interferometric detection method was developed at the FEIS-UNESP’s Optoelectronic Laboratory (LOE), constituting an improved version of the phase-unwrapping technique. This method is immune to the phenomenon of fading, can measure the delay time between the stimulus and the response, has a wide dynamic range, reconstructs the waveform of the modulation signal without the need of applying filters to the interferometric output, also possessing the ability to demodulate signals with non-periodic waveforms. Taking advantage of this information, the adaptation of the method to a high voltage optical sensor in a quadrature configuration was promoted. In this way, the present research deals with the study and development of a high voltage optical sensor with quadrature switching, based on Pockels cell, giving continuity to researches in the LOE of a high voltage electro-optical sensing system. The high voltage sensor with quadrature switching and phase controlled feedback was implemented and submitted to tests with voltage between 200 V and 8.4 kV (peak) at 60 Hz, with excellent linearity in the range of interest and good accuracy in measuring the harmonic content of the signals. These results show the potential of the system to operate in the analysis of electric power quality in systems of the class of 13.8 kV.
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Barrett, Dennis Ian. "Invariant optimal control on the three-dimensional semi-Euclidean group: control affine and quadratic Hamilton-Poisson systems." Thesis, Rhodes University, 2014. http://hdl.handle.net/10962/64805.
Анотація:
In this thesis we consider invariant control systems and Hamilton-Poisson systems on the three dimensional semi-Euclidean group SE(1,1). We first classify the left-invariant control affine systems (under detached feedback equivalence). We provide a complete list of normal forms, as well as classifying conditions. As a corollary to this classification, we derive controllability criteria for control affine systems on SE(1,1). Secondly, we consider quadratic Hamilton-Poisson systems on the (minus) Lie-Poisson space se(1,1)*. These systems are classified up to an affine isomorphism. Six normal forms are identified for the homogeneous case, whereas sixteen representatives (including several infinite families) are obtained for the inhomogeneous systems. Thereafter we consider the stability and integration of the normal forms obtained. For all homogeneous systems, and a subclass of inhomogeneous systems, we perform a complete stability analysis and derive explicit expressions for all integral curves. (The extremal controls of a large class of optimal control problems on SE(1,1) are linearly related to these integral curves.) Lastly, we discuss the Riemannian and sub-Riemannian problems. The (left-invariant) Riemannian and sub-Riemannian structures on SE(1,1) are classified, up to isometric group automorphisms and scaling. Explicit expressions for the geodesics of the normalised structures are found.
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McDowell, Journey. "Comparison of Modern Controls and Reinforcement Learning for Robust Control of Autonomously Backing Up Tractor-Trailers to Loading Docks." DigitalCommons@CalPoly, 2019. https://digitalcommons.calpoly.edu/theses/2100.
Анотація:
Two controller performances are assessed for generalization in the path following task of autonomously backing up a tractor-trailer. Starting from random locations and orientations, paths are generated to loading docks with arbitrary pose using Dubins Curves. The combination vehicles can be varied in wheelbase, hitch length, weight distributions, and tire cornering stiffness. The closed form calculation of the gains for the Linear Quadratic Regulator (LQR) rely heavily on having an accurate model of the plant. However, real-world applications cannot expect to have an updated model for each new trailer. Finding alternative robust controllers when the trailer model is changed was the motivation of this research.
Reinforcement learning, with neural networks as their function approximators, can allow for generalized control from its learned experience that is characterized by a scalar reward value. The Linear Quadratic Regulator and the Deep Deterministic Policy Gradient (DDPG) are compared for robust control when the trailer is changed. This investigation quantifies the capabilities and limitations of both controllers in simulation using a kinematic model. The controllers are evaluated for generalization by altering the kinematic model trailer wheelbase, hitch length, and velocity from the nominal case.
In order to close the gap from simulation and reality, the control methods are also assessed with sensor noise and various controller frequencies. The root mean squared and maximum errors from the path are used as metrics, including the number of times the controllers cause the vehicle to jackknife or reach the goal. Considering the runs where the LQR did not cause the trailer to jackknife, the LQR tended to have slightly better precision. DDPG, however, controlled the trailer successfully on the paths where the LQR jackknifed. Reinforcement learning was found to sacrifice a short term reward, such as precision, to maximize the future expected reward like reaching the loading dock. The reinforcement learning agent learned a policy that imposed nonlinear constraints such that it never jackknifed, even when it wasn't the trailer it trained on.
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Ho, Fusheng. "State-space LQG self-tuning control of flexible structures." Diss., This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-05042006-164519/.
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RÊGO, Patrícia Helena Moraes. "Aprendizagem por Reforço e Programação Dinâmica Aproximada para Controle Ótimo: Uma Abordagem para o Projeto Online do Regulador Linear Quadrático Discreto com Programação Dinâmica Heurística Dependente de Estado e Ação." Universidade Federal do Maranhão, 2014. http://tedebc.ufma.br:8080/jspui/handle/tede/1879.
Анотація:
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In this thesis a proposal of an uni ed approach of dynamic programming, reinforcement learning and function approximation theories aiming at the development of methods and algorithms for design of optimal control systems is presented. This approach is presented in the approximate dynamic programming context that allows approximating the optimal feedback solution as to reduce the computational complexity associated to the conventional dynamic programming methods for optimal control of multivariable systems. Speci cally, in the state and action dependent heuristic dynamic programming framework, this proposal is oriented for the development of online approximated solutions, numerically stable, of the Riccati-type Hamilton-Jacobi-Bellman equation associated to the discrete linear quadratic regulator problem which is based on a formulation that combines value function estimates by means of a RLS (Recursive Least-Squares) structure, temporal di erences and policy improvements. The development of the proposed methodologies, in this work, is focused mainly on the UDU T factorization that is inserted in this framework to improve the RLS estimation process of optimal decision policies of the discrete linear quadratic regulator, by circumventing convergence and numerical stability problems related to the covariance matrix ill-conditioning of the RLS approach.
Apresenta-se nesta tese uma proposta de uma abordagem uni cada de teorias de programação dinâmica, aprendizagem por reforço e aproximação de função que tem por objetivo o desenvolvimento de métodos e algoritmos para projeto online de sistemas de controle ótimo. Esta abordagem é apresentada no contexto de programação dinâmica aproximada que permite aproximar a solução de realimentação ótima de modo a reduzir a complexidade computacional associada com métodos convencionais de programação dinâmica para controle ótimo de sistemas multivariáveis. Especi camente, no quadro de programação dinâmica heurística e programação dinâmica heurística dependente de ação, esta proposta é orientada para o desenvolvimento de soluções aproximadas online, numericamente estáveis, da equação de Hamilton-Jacobi-Bellman do tipo Riccati associada ao problema do regulador linear quadrático discreto que tem por base uma formulação que combina estimativas da função valor por meio de uma estrutura RLS (do inglês Recursive Least-Squares), diferenças temporais e melhorias de política. O desenvolvimento das metodologias propostas, neste trabalho, tem seu foco principal voltado para a fatoração UDU T que é inserida neste quadro para melhorar o processo de estimação RLS de políticas de decisão ótimas do regulador linear quadrá- tico discreto, contornando-se problemas de convergência e estabilidade numérica relacionados com o mal condicionamento da matriz de covariância da abordagem RLS.
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Carnevale, Guido. "Control-based Design and Analysis of Gradient-Tracking Algorithms for Distributed Quadratic Optimization." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019.
Анотація:
In this work we design an iterative distributed optimization algorithm, based on the well-known distributed gradient tracking algorithm. We show the advantages of a system theoretical approach on a distributed optimization framework in which the cost function is
given by a sum of quadratic functions. In other words, the main idea of the work consists in seeing the update equation characterizing an iterative optimization algorithm as the dynamics equation of a discrete-time system in which the decision variable plays the state
variable role. The goal of the work is to show how system and control theory tools can be used to force this state variable to the optimum of the considered cost function even in presence of disturbances and/or uncertainties. So, the design of a distributed optimization algorithm is seen as the design of a controller able to solve the set point control problem in which the reference signal is given by the optimum of the considered cost function.