Página 1 dos resultados de 6937 itens digitais encontrados em 0.031 segundos

## Robust STATCOM control for the stabilisation of fixed-speed wind turbines during low voltages

HOSSAIN, M. J.; POTA, H. R.; RAMOS, R. A.
Fonte: PERGAMON-ELSEVIER SCIENCE LTD Publicador: PERGAMON-ELSEVIER SCIENCE LTD
Tipo: Artigo de Revista Científica
ENG
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This paper presents a robust voltage control scheme for fixed-speed wind generators using a static synchronous compensator (STATCOM) controller. To enable a linear and robust control framework with structured uncertainty, the overall system is represented by a linear part plus a nonlinear part that covers an operating range of interest required to ensure stability during severe low voltages. The proposed methodology is flexible and readily applicable to larger wind farms of different configurations. The performance of the control strategy is demonstrated on a two area test system. Large disturbance simulations demonstrate that the proposed controller enhances voltage stability as well as transient stability of induction generators during low voltage ride through (LVRT) transients and thus enhances the LVRT capability. (C) 2011 Elsevier Ltd. All rights reserved.

## Controle robusto de dispositivos FACTS para o amortecimento de oscilações em sistemas elétricos de potência; Robust control of FACTS devices to damp oscillations in electric power systems

Kuiava, Rôman
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
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## Controle robusto de suspensão semi-ativa para caminhonetes utilizando amortecedores magneto-reológicos.; Robust control of a semi-active pickup truck suspension using magneto-rheological dampers.

Crivellaro, Cláudio
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
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A utilização de sistemas semi-ativos no controle de movimento e vibração vem crescendo muito nos últimos anos, e está se firmando como a opção mais econômica em muitas aplicações. Os sistemas de controle semi-ativos baseados em fluidos magneto-reológicos (MR) já são empregados no controle de vibrações desde máquinas de lavar a grandes pontes suspensas, e até mesmo no controle de vibração de edifícios sujeitos a abalos sísmicos. No controle de movimento, eles têm sido aplicados em aparelhos de fisioterapia, próteses de joelho humano e embreagens. No setor automobilístico, os sistemas semi-ativos são empregados em sistemas de controle da suspensão e sistemas anti-rolagem, e também no controle de sistemas de torque e tração. Visto a crescente importância dos sistemas de controle semi-ativo, este trabalho aborda este assunto dividindo-o em duas partes: a primeira, apresentada no volume 1, trata do projeto de atuadores magneto-reológicos e do seu modelamento dinâmico voltado para projetos de controle; e a segunda parte, apresentada no volume 2, trata de projeto de controladores para sistemas semi-ativos, mais especificamente voltados para o controle de suspensão veicular semi-ativa, buscando a melhoria do desempenho em conforto...

## Controle robusto de sistemas de potência multimáquinas através de desigualdades matriciais lineares: abordagem por alocação de pólos e ajuste de estabilizadores de sistemas de potência.; Robust control of multimachine power systems through linear matrix inequalities: the pole placement approach with power system stabilizers adjustment.

Campos, Victor Augusto Fernandes de
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
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## Controle robusto descentralizado de movimentos coordenados de robôs heterogêneos; Decentralized robust control of coordinated movements of heterogeneous robots

Inoue, Roberto Santos
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
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Este trabalho trata da coordenação de robôs heterogêneos que consiste em um robô helicóptero e em múltiplos robôs móveis com rodas, de modo que estes sigam um líder. Para atingirmos este objetivo, neste trabalho desenvolve-se a estimação da atitude e posição de um robô utilizando filtros robustos. Os filros realizam a fusão dos sinais de uma unidade de medida inercial de baixo custo e de um receptor GPS (Global Positioning System) considerando um modelo de corpo rígido formulado em termos de quatérnios. Resultados experimentais são apresentados baseados em um estudo comparativo entre os filtros robustos e o filtro de Kalman. Desenvolve-se o controle de um robô móvel com rodas deslizantes e de um robô helicóptero. Para realizar o controle robusto utilzia-se um regulador robusto recursivo. Simulaçõoes do robô móvel com rodas deslizantes e do robô helicóptero são apresentadas utilizando os parâmetros de um robô móvel Pioneer 3AT e de um robô helicóptero RMAX. Desenvolve-se também um mini robô helicóptero e uma base de movimento para realização de testes de controle do mini robô helicóptero constiste de um mini helimodelo e de um piloto automático baseado em um microprocessador com conectividade Wi-Fi...

## Robust control applications for smart truss structure

Carvalhal, Ricardo; Da Silva, Samuel; Júnior, Vicente Lopes
Tipo: Conferência ou Objeto de Conferência
ENG
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A finite element modeling of an intelligent truss structure with piezoelectric stack actuators for the purpose of active damping and structural vibration attenuation is presented. This paper concerns with the following issues aspects: the design of intelligent truss structure considering electro-mechanical coupling between the host structure and piezoelectric stack actuators; the H 2 norm approach to search for optimal placement of actuators and sensors; and finally some aspects in robust control techniques. The electro-mechanical behavior of piezoelectric elements is directly related to the successful application of the actuators in truss structures. In order to achieve the desired damping in the interested bandwidth frequency it is used the H ∞ output feedback solved by convex optimization. The constraints to be reached are written by linear matrix inequalities (LMI). The paper concludes with a numerical example, using Matlab and Simulink, in a cantilevered, 2-bay space truss structure. The results demonstrated the approach applicability.

## Multivariable robust control of an integrated nuclear power reactor

Etchepareborda,A.; Flury,C.A.
Fonte: Brazilian Society of Chemical Engineering Publicador: Brazilian Society of Chemical Engineering
Tipo: Artigo de Revista Científica Formato: text/html
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The design of the main control system of the CAREM nuclear power plant is presented. This plant is an inherently safe low-power nuclear reactor with natural convection on the primary coolant circuit and is self-pressurized with a steam dome on the top of the pressure vessel (PV). It is an integrated reactor as the whole primary coolant circuit is within the PV. The primary circuit transports the heat to the secondary circuit through once-through steam generators (SG). There is a feedwater valve at the inlet of the SG and a turbine valve at the outlet of the SG. The manipulated variables are the aperture of these valves and the reactivity of the control rods. The control target is to regulate the primary and secondary pressures and to monitor steam flow reference ramps on a range of nominal flow from 100% to 40%. The requirements for the control system are robust stability, low-order simple controllers and transient/permanent error bounding. The controller design is based on a detailed RETRAN plant model, from which linear perturbed open-loop dynamic models at different powers are identified. Two low-order nominal models with their associated uncertainties are chosen for two different power ranges. Robust controllers with acceptable performances are designed for each range. Numerical optimization based on the loop-shaping method is used for the controller design. The designed controllers are implemented in the RETRAN model and tested in simulations achieving successful results.

## Uma contribuição ao estudo de controladores robustos; A contribution for studing of robust control

Silva, Cláudio Homero Ferreira da
POR
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## Robust Control For Underwater Vehicle Systems With Time Delays

Triantafyllou, Michael S .; Grosenbaugh, Mark A.
Fonte: Institute of Electrical and Electronic Engineers Publicador: Institute of Electrical and Electronic Engineers
Tipo: Artigo de Revista Científica Formato: 569726 bytes; application/pdf
EN_US
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Presented in this paper is a robust control scheme for controlling systems with time delays. The scheme is based on the Smith controller and the LQG/LTR (Linear Quadratic Gaussian/Loop Transfer Recovery) methodology. The methodology is applicable to undenvater vehicle systems that exhibit time delays, including tethered vehicles that are positioned through the movements of a surface ship and autonomous vehicles that are controlled through an acoustic link. An example, using full-scale data from the Woods Hole Oceanographic Institution’s tethered vehicle ARGO, demonstrates the developments.

## Modelling and uncertainties characterization for robust control

Figueroa, Jose Luis; Biagiola, Silvina Ines
Fonte: Elsevier Sci Ltd Publicador: Elsevier Sci Ltd
Tipo: info:eu-repo/semantics/article; info:ar-repo/semantics/artículo; info:eu-repo/semantics/publishedVersion Formato: application/pdf
ENG
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In this work, multi-input multi-output (MIMO) process identification is studied, where the model identification is dedicated to the control design goal. An ad hoc identification procedure is presented which allows estimating not only a nominal parametric process model, but also a bound of the model uncertainty (i.e. modelling errors). The model structure is defined in a way that the identified nominal model and the uncertainties can readily be used for the analysis and design of a robust control system by means of many of the techniques available in the literature. Simulation examples are given to illustrate the method.; Fil: Figueroa, Jose Luis. Consejo Nacional de Invest.cientif.y Tecnicas. Centro Cientifico Tecnol.conicet - Bahia Blanca. Instituto de Invest.en Ing.Electrica; Argentina;; Fil: Biagiola, Silvina Ines. Consejo Nacional de Invest.cientif.y Tecnicas. Centro Cientifico Tecnol.conicet - Bahia Blanca. Instituto de Invest.en Ing.Electrica; Argentina;

## Decentralized robust control of uncertain Markov jump parameter systems via output feedback

Li, Li; Ugrinovskii, Valery A; Orsi, Robert
Fonte: Pergamon-Elsevier Ltd Publicador: Pergamon-Elsevier Ltd
Tipo: Artigo de Revista Científica
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This paper addresses the problem of decentralized robust stabilization and control for a class of uncertain Markov jump parameter systems. Control is via output feedback and knowledge of the discrete Markov state. It is shown that the existence of a solut

## Partially Independent Robust Control for Thrust-Limited Rendezvous in Near-Circular Orbits

Wan, Neng; Liu, Ming
Tipo: Artigo de Revista Científica
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Space environment is so complex and changeable that an accurate model of spacecraft rendezvous is difficult to obtain, which consequently complicates the rendezvous control task. In order to realize the robust stability as well as to optimize the time and fuel cost of the rendezvous process, a linearized rendezvous model with parametric uncertainty and a partially independent robust controller are proposed in this paper. In-plane and out-of-plane motion models are established separately in the presence of external disturbance and non-circularity of the target's orbit. The partially independent controller is integrated with an in-plane robust guaranteed cost controller and an out-of-plane robust $H_{\infty}$ controller. A numerical rendezvous example is presented to illustrate the usefulness and advantages of the partially independent robust control scheme.; Comment: Some crucial errors has been found in this paper

## Adaptive-Robust Control of a Class of Uncertain Nonlinear Systems Utilizing Time-Delayed Input and Position Feedback

Roy, Spandan; Kar, Indra Narayan
Tipo: Artigo de Revista Científica
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In this paper, the tracking control problem of a class of Euler-Lagrange systems subjected to unknown uncertainties is addressed and an adaptive-robust control strategy, christened as Time-Delayed Adaptive Robust Control (TARC) is presented. The proposed control strategy approximates the unknown dynamics through time-delayed logic, and the switching logic provides robustness against the approximation error. The novel adaptation law for the switching gain, in contrast to the conventional adaptive-robust control methodologies, does not require either nominal modelling or predefined bounds of the uncertainties. Also, the proposed adaptive law circumvents the overestimation-underestimation problem of switching gain. The state derivatives in the proposed control law is estimated from past data of the state to alleviate the measurement error when state derivatives are not available directly. Moreover, a new stability notion for time-delayed control is proposed which in turn provides a selection criterion for controller gain and sampling interval. Experimental result of the proposed methodology using a nonholonomic wheeled mobile robot (WMR) is presented and improved tracking accuracy of the proposed control law is noted compared to time-delayed control and adaptive sliding mode control.; Comment: 17 pages...

## Risk Analysis in Robust Control -- Making the Case for Probabilistic Robust Control

Chen, Xinjia; Aravena, Jorge; Zhou, Kemin
Tipo: Artigo de Revista Científica
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This paper offers a critical view of the "worst-case" approach that is the cornerstone of robust control design. It is our contention that a blind acceptance of worst-case scenarios may lead to designs that are actually more dangerous than designs based on probabilistic techniques with a built-in risk factor. The real issue is one of modeling. If one accepts that no mathematical model of uncertainties is perfect then a probabilistic approach can lead to more reliable control even if it cannot guarantee stability for all possible cases. Our presentation is based on case analysis. We first establish that worst-case is not necessarily "all-encompassing." In fact, we show that for some uncertain control problems to have a conventional robust control solution it is necessary to make assumptions that leave out some feasible cases. Once we establish that point, we argue that it is not uncommon for the risk of unaccounted cases in worst-case design to be greater than that of the accepted risk in a probabilistic approach. With an example, we quantify the risks and show that worst-case can be significantly more risky. Finally, we join our analysis with existing results on computational complexity and probabilistic robustness to argue that the deterministic worst-case analysis is not necessarily the better tool.; Comment: 22 pages...

## Distributed Robust Control of Linear Multi-Agent Systems with Parameter Uncertainties

Li, Zhongkui; Duan, Zhisheng; Xie, Lihua; Liu, Xiangdong
Tipo: Artigo de Revista Científica
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This paper considers the distributed robust control problems of uncertain linear multi-agent systems with undirected communication topologies. It is assumed that the agents have identical nominal dynamics while subject to different norm-bounded parameter uncertainties, leading to weakly heterogeneous multi-agent systems. Distributed controllers are designed for both continuous- and discrete-time multi-agent systems, based on the relative states of neighboring agents and a subset of absolute states of the agents. It is shown for both the continuous- and discrete-time cases that the distributed robust control problems under such controllers in the sense of quadratic stability are equivalent to the $H_\infty$ control problems of a set of decoupled linear systems having the same dimensions as a single agent. A two-step algorithm is presented to construct the distributed controller for the continuous-time case, which does not involve any conservatism and meanwhile decouples the feedback gain design from the communication topology. Furthermore, a sufficient existence condition in terms of linear matrix inequalities is derived for the distributed discrete-time controller. Finally, the distributed robust $H_\infty$ control problems of uncertain linear multi-agent systems subject to external disturbances are discussed.; Comment: 17 pages...

## Robust control through robustness enhancement control configurations and two-step design approaches /

Pedret Ferré, Carles
Fonte: Bellaterra : Universitat Autònoma de Barcelona, Publicador: Bellaterra : Universitat Autònoma de Barcelona,
Tipo: Tesis i dissertacions electròniques; info:eu-repo/semantics/doctoralThesis Formato: application/pdf
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## Robust control strategies for hybrid solid oxide fuel cell systems

Allag, Tahar
Fonte: Rochester Instituto de Tecnologia Publicador: Rochester Instituto de Tecnologia
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Solid Oxide Fuel Cell (SOFC) systems are electrochemical energy conversion devices characterized by the use of solid oxide as the electrolyte. They operate at high temperatures (between 800± ¡ 1000±C). Mitigating fuel starvation and improving load-following capability of SOFCs are conflicting control objectives. In this thesis, this issue is addressed using a hybrid SOFC ultra-capacitor configuration. The fuel cell is controlled by incorporating a steady-state property of fuel utilization into an input-shaping framework. Two comprehensive control strategies are developed. The first is a Lyapunov-based nonlinear control and the second is a standard H-infinity robust control. Both strategies additionally control the state of charge (SOC) of the ultra-capacitor that provides transient power compensation. A hardware-in-the-loop test-stand is developed where the proposed control strategies are verified. An investigation to improve the hybrid fuel cell system by incorporating a lithium-ion battery as an additional power source is conducted. Combining both battery and ultra-capacitor with a fuel cell is potentially a winning combination especially for high power applications. A novel SOC estimation method for lithium-ion battery is investigated. Based on the combined ultra-capacitor battery hybrid system...

## Optimal economic planning and control for the management of ecosystems

Macksamie, Kevin
Fonte: Rochester Instituto de Tecnologia Publicador: Rochester Instituto de Tecnologia
EN_US
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In recent years the interest on sustainable systems has increased significantly. Among the many interested problems, creating and restoring sustainable ecosystems is a challenging and complex problem. One of the fundamental problems within this area is the imbalance between species that have a predator-prey relationship. Solutions involving management have become an integral player in many environments. Management systems typically use ad hoc methods to develop harvesting policies to control the populations of species to desired numbers. In order to amalgamate intelligence and structure, ecological systems require a diverse research effort from three primary fields: ecology, economics, and control theory. In this thesis, all three primary fields aforementioned are researched to develop a theoretical framework that includes an optimal trajectory planning system that exploits an ecosystem to maximize profits for the supporting community, and a robust control system design to track the optimal trajectories subjected to exogenous disturbances. Population ecology is used to select a model that identifies the key characteristics a management system needs to understand the behavior of the natural environment. A bioeconomic model is developed to relate the species populations to revenue. The nonlinear ecosystem is transformed into a linear parameter-varying (LPV) system that is then controlled using hinf synthesis and the gain scheduling methodology. The consequences of the results in this thesis are that optimal trajectories of an ecosystem can be obtained by constructing and solving a nonlinear programming problem (NLP)...

## L ∞ -bounded robust control of nonlinear cascade systems

Huang, Shoudong; James, Matthew; Jiang, Zhong-Ping