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## Controle não linear aplicado a dispositivos FACTS em sistemas elétricos de potência; Nonlinear control applied to FACTS devices in power systems

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

Publicado em 24/04/2012
PT

Relevância na Pesquisa

65.9%

#Controle não linear#Dispositivos FACTS#Dispositivos TCSC#FACTS devices#Função energia generalizada#Função energia generalizada de controle#Generalized energy function#Generalized energy function of control#Nonlinear control#TCSC devices

O TCSC é um dos compensadores dinâmicos mais eficazes empregados em Sistemas Elétricos de Potência, pois, oferece um ajuste flexível, de forma rápida e confiável, possibilitando a aplicação de teorias avançadas no seu controle. Estes dispositivos podem desempenhar funções importantes para a operação e o controle do sistema, trazendo inúmeros benefícios. Devido aos benefícios que o uso deste dispositivo oferece, uma grande quantidade de trabalhos vem sendo desenvolvidos com o intuito de sintetizar leis de controle para o mesmo. Porém, a maioria destes trabalhos é fundamentado em técnicas de controle clássico, isto é, projetando leis de controle baseado em sistemas linearizados e para pontos específicos da operação. Estas técnicas de análise entretanto, não garantem que para perturbações que levam o sistema para pontos distantes daqueles usados no projeto do controlador, a atuação do controlador seja eficaz e contribua assim para a estabilização do sistema. Visando o estudo mais aprofundado dos fenômenos que ocorrem nos sistemas físicos, modelos não lineares vêm sendo empregados, e as técnicas de projeto de controladores baseadas nesses modelos, são cada vez mais desenvolvidas. Neste trabalho será empregada a técnica de controle não linear baseada na Função Energia Generalizada de Controle para síntese de leis de controles estabilizantes para os dispositivos TCSC considerando...

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## Optimal linear and nonlinear control design for chaotic systems

Fonte: Universidade Estadual Paulista
Publicador: Universidade Estadual Paulista

Tipo: Conferência ou Objeto de Conferência
Formato: 867-873

ENG

Relevância na Pesquisa

75.93%

#Chaos theory#Computer simulation#Dynamic programming#Feedback control#Hamiltonians#Nonlinear control systems#Optimal control systems#Oscillations#Duffing oscillator#Hamilton Jacobi Bellman equation#Optimal control theory

In this work, the linear and nonlinear feedback control techniques for chaotic systems were been considered. The optimal nonlinear control design problem has been resolved by using Dynamic Programming that reduced this problem to a solution of the Hamilton-Jacobi-Bellman equation. In present work the linear feedback control problem has been reformulated under optimal control theory viewpoint. The formulated Theorem expresses explicitly the form of minimized functional and gives the sufficient conditions that allow using the linear feedback control for nonlinear system. The numerical simulations for the Rössler system and the Duffing oscillator are provided to show the effectiveness of this method. Copyright © 2005 by ASME.

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## Phase Space Navigator: Towards Automating Control Synthesis in Phase Spaces for Nonlinear Control Systems

Fonte: MIT - Massachusetts Institute of Technology
Publicador: MIT - Massachusetts Institute of Technology

Formato: 31 p.; 4810612 bytes; 3851493 bytes; application/postscript; application/pdf

EN_US

Relevância na Pesquisa

75.85%

#automated control synthesis#intelligent control#nonlinearscontrol#knowledge-based systems#planning and simulation#autonomousssystems#dynamical systems#knowledge representation#numeric/symbolicsprocessing.

We develop a novel autonomous control synthesis strategy called Phase Space Navigator for the automatic synthesis of nonlinear control systems. The Phase Space Navigator generates global control laws by synthesizing flow shapes of dynamical systems and planning and navigating system trajectories in the phase spaces. Parsing phase spaces into trajectory flow pipes provide a way to efficiently reason about the phase space structures and search for global control paths. The strategy is particularly suitable for synthesizing high-performance control systems that do not lend themselves to traditional design and analysis techniques.

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## Discrete Verification of Necessary Conditions for Switched Nonlinear Optimal Control Systems, ACA (2004; Boston, Massachusetts)

Fonte: IEEE
Publicador: IEEE

Tipo: Conference Paper

Relevância na Pesquisa

75.88%

The article of record as published may be located at http://ieeexplore.ieee.org; Approved for public display, distribution unlimited; Proceeding of the 2004 American Control Conference Boston, Massachusetts ; vol. 2, page(s):1610-1615, June 30-July 2, 2004; We consider a fairly general class of state-constrained nonlinear hybrid optimal control problems that are based on coordinatizing Sussmann's model. An event set generalizes the notion of a guard set, reset map, endpoint set as well as the switching set. We present a pseudospectral (PS) knotting method that discretizes the continuous-time variables of the problem. The discrete event conditions are imposed over the PS knots leading to a large, sparse, mixed-variable programming (MVP) problem. The Karush-Kuhn-Tucker conditions for the MVP are transformed in a manner that makes them closely resemble the discretized necessary conditions obtained from the hybrid minimum principle. A set of closure conditions are introduced to facilitate commuting the operations of dualization and discretization. An immediate consequence of this is a hybrid covector mapping theorem that provides an order-preserving transformation of the Lagrange multipliers associated with the discretized problem to the discretized covectors associated with the hybrid optimal control problem.

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## Dissipative Decomposition and Feedback Stabilization of Nonlinear Control Systems

Fonte: Quens University
Publicador: Quens University

Tipo: Tese de Doutorado

EN; EN

Relevância na Pesquisa

85.92%

This dissertation considers the problem of approximate dissipative potentials construction and their use in smooth feedback stabilization of nonlinear control systems. For mechanical systems, dissipative potentials, usually a generalized Hamiltonian function, can be derived from physical intuition. When a dissipative Hamiltonian is not available, one can rely on dissipative Hamiltonian realization techniques, as proposed recently by Cheng and coworkers. Extensive results are available in the literature for (robust) stabilization based on the obtained potential.
For systems of interest in chemical engineering, especially systems with mass action kinetics, energy is often ill-defined. Moreover, realization techniques are difficult to apply, due to the nonlinearities associated with the reaction terms. Approximate dissipative realization techniques have been considered by many researchers for analysis and feedback design of controllers in the context of chemical processes. The objective of this thesis is to study the
construction of local dissipative potentials and their application to solve stabilization problems.
The present work employs the geometric stabilization approach proposed by Jurdjevic and Quinn, refined by Faubourg and Pomet...

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## Flexible Nonlinear Voltage Control Design for Power Systems

Fonte: Institute of Electrical and Electronics Engineers (IEEE Inc)
Publicador: Institute of Electrical and Electronics Engineers (IEEE Inc)

Tipo: Conference paper

Relevância na Pesquisa

65.86%

#Keywords: Direct Feedback Linearization (DFL)#Single machine infinite bus (SMIB)#Computer simulation#Electric power systems#Feedback linearization#Nonlinear control systems#Voltage control

This paper presents the Direct Feedback Linearization (DFL) technique as a simple and flexible nonlinear control method in designing robust nonlinear excitation controllers for stability enhancement and voltage regulation of power systems. This technique

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## Thomas decompositions of parametric nonlinear control systems

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Publicado em 03/12/2012

Relevância na Pesquisa

75.77%

This paper presents an algorithmic method to study structural properties of
nonlinear control systems in dependence of parameters. The result consists of a
description of parameter configurations which cause different control-theoretic
behaviour of the system (in terms of observability, flatness, etc.). The
constructive symbolic method is based on the differential Thomas decomposition
into disjoint simple systems, in particular its elimination properties.

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## Model Reduction for Nonlinear Control Systems using Kernel Subspace Methods

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Relevância na Pesquisa

75.86%

#Mathematics - Optimization and Control#Computer Science - Systems and Control#Mathematics - Dynamical Systems#Statistics - Machine Learning

We introduce a data-driven order reduction method for nonlinear control
systems, drawing on recent progress in machine learning and statistical
dimensionality reduction. The method rests on the assumption that the nonlinear
system behaves linearly when lifted into a high (or infinite) dimensional
feature space where balanced truncation may be carried out implicitly. This
leads to a nonlinear reduction map which can be combined with a representation
of the system belonging to a reproducing kernel Hilbert space to give a closed,
reduced order dynamical system which captures the essential input-output
characteristics of the original model.
Empirical simulations illustrating the approach are also provided.

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## On the output-input stability property for multivariable nonlinear control systems

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Publicado em 19/05/2002

Relevância na Pesquisa

75.8%

We study the recently introduced notion of output-input stability, which is a
robust variant of the minimum-phase property for general smooth nonlinear
control systems. The subject of this paper is developing the theory of
output-input stability in the multi-input, multi-output setting. We show that
output-input stability can be viewed as a combination of two system properties,
one related to detectability and the other to left-invertibility. For systems
affine in controls, we provide a necessary and sufficient condition for
output-input stability, which relies on Hirschorn's nonlinear structure
algorithm.

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## Symbolic models for nonlinear control systems affected by disturbances

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Publicado em 26/01/2012

Relevância na Pesquisa

75.86%

In the last few years there has been a growing interest in the use of
symbolic models for the formal veri?cation and control design of purely
continuous or hybrid systems. Symbolic models are abstract descriptions of
continuous systems where one symbol corresponds to an "aggregate" of continuous
states. In this paper we face the problem of deriving symbolic models for
nonlinear control systems affected by disturbances. The main contribution of
this paper is in proposing symbolic models that can be eff?ectively constructed
and that approximate nonlinear control systems aff?ected by disturbances in the
sense of alternating approximate bisimulation.; Comment: 14 pages, 3 figures

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## Discrete Control Systems

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Publicado em 26/05/2007

Relevância na Pesquisa

65.95%

Discrete control systems, as considered here, refer to the control theory of
discrete-time Lagrangian or Hamiltonian systems. These discrete-time models are
based on a discrete variational principle, and are part of the broader field of
geometric integration. Geometric integrators are numerical integration methods
that preserve geometric properties of continuous systems, such as conservation
of the symplectic form, momentum, and energy. They also guarantee that the
discrete flow remains on the manifold on which the continuous system evolves,
an important property in the case of rigid-body dynamics.
In nonlinear control, one typically relies on differential geometric and
dynamical systems techniques to prove properties such as stability,
controllability, and optimality. More generally, the geometric structure of
such systems plays a critical role in the nonlinear analysis of the
corresponding control problems. Despite the critical role of geometry and
mechanics in the analysis of nonlinear control systems, nonlinear control
algorithms have typically been implemented using numerical schemes that ignore
the underlying geometry.
The field of discrete control system aims to address this deficiency by
restricting the approximation to choice of a discrete-time model...

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## A Vector Small-Gain Theorem for General Nonlinear Control Systems

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Publicado em 05/04/2009

Relevância na Pesquisa

75.9%

A new Small-Gain Theorem is presented for general nonlinear control systems.
The novelty of this research work is that vector Lyapunov functions and
functionals are utilized to derive various input-to-output stability and
input-to-state stability results. It is shown that the proposed approach
recovers several recent results as special instances and is extendible to
several important classes of control systems such as large-scale complex
systems, nonlinear sampled-data systems and nonlinear time-delay systems. An
application to a biochemical circuit model illustrates the generality and power
of the proposed vector small-gain theorem.; Comment: Submitted to IEEE Transactions on Automatic Control

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## Symbolic Models for Nonlinear Control Systems: Alternating Approximate Bisimulations

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Publicado em 27/07/2007

Relevância na Pesquisa

75.84%

Symbolic models are abstract descriptions of continuous systems in which
symbols represent aggregates of continuous states. In the last few years there
has been a growing interest in the use of symbolic models as a tool for
mitigating complexity in control design. In fact, symbolic models enable the
use of well known algorithms in the context of supervisory control and
algorithmic game theory, for controller synthesis. Since the 1990's many
researchers faced the problem of identifying classes of dynamical and control
systems that admit symbolic models. In this paper we make a further progress
along this research line by focusing on control systems affected by
disturbances. Our main contribution is to show that incrementally globally
asymptotically stable nonlinear control systems with disturbances admit
symbolic models. When specializing these results to linear systems, we show
that these symbolic models can be easily constructed.

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## Quasiperiodic AlGaAs superlattices for neuromorphic networks and nonlinear control systems

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Publicado em 08/02/2015

Relevância na Pesquisa

75.81%

#Condensed Matter - Mesoscale and Nanoscale Physics#Nonlinear Sciences - Chaotic Dynamics#Quantum Physics

The application of quasiperiodic AlGaAs superlattices as a nonlinear element
of the FitzHugh-Nagumo neuromorphic network is proposed and theoretically
investigated on the example of Fibonacci and figurate superlattices. The
sequences of symbols for the figurate superlattices were produced by
decomposition of the Fibonacci superlattices' symbolic sequences. A length of
each segment of the decomposition was equal to the corresponding figurate
number. It is shown that a nonlinear network based upon Fibonacci and figurate
superlattices provides better parallel filtration of a half-tone picture than a
network based upon traditional diodes which have cubic voltage-current
characteristics. It was found that the figurate superlattice F011(1) as a
nonlinear network's element provides the filtration error almost twice less
than the conventional "cubic" diode. These advantages are explained by a
wavelike shape of the decreasing part of the quasiperiodic superlattice's
voltage-current characteristic, which leads to multistability of the network's
cell. This multistability promises new interesting nonlinear dynamical
phenomena. A variety of wavy forms of voltage-current characteristics opens up
new interesting possibilities for quasiperiodic superlattices and especially
for figurate superlattices in many areas - from nervous system modeling to
nonlinear control systems development; Comment: 19 pages...

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## Balanced Reduction of Nonlinear Control Systems in Reproducing Kernel Hilbert Space

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Publicado em 12/11/2010

Relevância na Pesquisa

75.83%

#Mathematics - Optimization and Control#Mathematics - Dynamical Systems#Mathematics - Statistics Theory#Statistics - Machine Learning

We introduce a novel data-driven order reduction method for nonlinear control
systems, drawing on recent progress in machine learning and statistical
dimensionality reduction. The method rests on the assumption that the nonlinear
system behaves linearly when lifted into a high (or infinite) dimensional
feature space where balanced truncation may be carried out implicitly. This
leads to a nonlinear reduction map which can be combined with a representation
of the system belonging to a reproducing kernel Hilbert space to give a closed,
reduced order dynamical system which captures the essential input-output
characteristics of the original model. Empirical simulations illustrating the
approach are also provided.

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

Fonte: Elsevier
Publicador: Elsevier

Tipo: Artigo de Revista Científica

Relevância na Pesquisa

75.94%

#Keywords: Closed loop control systems#Control equipment#Dynamic programming#Feedback control#Mathematical models#Nonlinear control systems#Problem solving#Backstepping#Internal stability#L8-bound#Nonlinear cascade systems

In this paper, we consider the L∞-bounded robust control problem for a class of nonlinear cascade systems with disturbances. Sufficient conditions are provided under which a hard bound is imposed on the system performance measure. The backstepping appro

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## Iterative Controller Optimization for Nonlinear Systems

Fonte: Pergamon-Elsevier Ltd
Publicador: Pergamon-Elsevier Ltd

Tipo: Artigo de Revista Científica

Relevância na Pesquisa

65.92%

#Keywords: Closed loop control systems#Control equipment#Iterative methods#Model-free control design#Nonlinear control systems#non-linear system#optimization Controller optimization#Estimation#Nonlinear control#Optimal control

Recently, a data-driven model-free control design method has been proposed in Hjalmarsson et al. (Proceedings of the Conference on Decision and Control, Orlando, FL, 1994, pp. 1735-1740; IEEE Control Systems Mag. 18 (1998) 26) for linear systems. It is based on the minimization of a control criterion with respect to the controller parameters using an iterative gradient technique. In this paper, we extend this method to the case where both the plant and the controller can be nonlinear. It is shown that an estimate of the gradient of the control criterion can be constructed using only signal-based information obtained from closed-loop experiments. The obtained estimate contains a bias which depends on the local nonlinearity of the noise description of the closed-loop system which can be expected to be small in many practical situations. As a side effect the linear model-free control design method is reobtained in a new way.

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## Recursive Identification of Nonlinear Plants Operating in Closed Loop Using Kernel Representations

Fonte: Pergamon-Elsevier Ltd
Publicador: Pergamon-Elsevier Ltd

Tipo: Artigo de Revista Científica

Relevância na Pesquisa

65.92%

#Keywords: Adaptive systems#Algorithms#Closed loop control systems#Degrees of freedom (mechanics)#Identification (control systems)#Recursive functions#Kernel representations#Nonlinear control systems Adaptive systems#Closed-loop identification#Kernel representations#Nonlinear systems

In this paper, we extend the family of algorithms presented in Algorithms for identification of continuous time nonlinear systems. A passivity approach. In A. Isidori, F. Ramnabhi-Lagarrigue, & W. Respondek (Eds.), Nonlinear control in the year 2000, vol. 2 (pp. 13-44) Berlin: Springer; (Automatica 37 (2000) 469) for the identification of continuous time nonlinear plants operating in closed loop. The new algorithms presuppose that one can construct a stable kernel representation for the "to be identified model" structure. The new theory results in a less restrictive passivity condition. The main novelty is that the identification of unstable plants can be tackled by an appropriate choice of the kernel representation, i.e. there is an additional degree of freedom when constructing the kernel representation. The implicit stability of the controller is still required by the new passivity condition.

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## Nonlinear H-∞ Control: Practicality of Implementing the Cheap Sensor Case

Fonte: Institute of Electrical and Electronics Engineers (IEEE Inc)
Publicador: Institute of Electrical and Electronics Engineers (IEEE Inc)

Tipo: Conference paper

Relevância na Pesquisa

75.86%

#Keywords: Closed loop control systems#Computational complexity#Control equipment#State feedback#Theorem proving#Information states#Nonlinear control systems Information states#Nonlinear H8 control#Reduced order observers#Reduction of computational complexity

In [5] we introduced a recipe for nonlinear H∞ controllers which takes advantage of extra perfect measurements and stated a theorem to the effect that this controller yielded the best possible "H∞" performance. Pure state feedback is an extreme situat

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## On Hybrid Impulsive and Switching Systems and Application to Nonlinear Control

Fonte: Institute of Electrical and Electronics Engineers (IEEE Inc)
Publicador: Institute of Electrical and Electronics Engineers (IEEE Inc)

Tipo: Artigo de Revista Científica

Relevância na Pesquisa

65.87%

#Keywords: Asymptotic stability#Chaos theory#Functions#Lyapunov methods#Mathematical models#Matrix algebra#System stability#Chaos control#Exponential stability#Hybrid systems#Switched Lyapunov function

In this note, a new class of hybrid impulsive and switching models is introduced and their asymptotic stability properties are investigated. Using switched Lyapunov functions, some new general criteria for exponential stability and asymptotic stability with arbitrary and conditioned impulsive switching are established. In addition, a new hybrid impulsive and switching control strategy for nonlinear systems is developed. A typical example, the unified chaotic system, is given to illustrate the theoretical results.

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