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## Estimação algébrica aplicada aos sistemas de controle - um estudo de casos.; Algebraic estimation applied to control systems: a case study.

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 20/06/2011
PT

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55.8%

#Álgebra diferencial#Control (systems and control theory)#Controle (teoria de sistemas e controle)#Differential algebra#Dynamical systems#Nonlinear systems#Sistemas dinâmicos#Sistemas não lineares

Esta proposta de dissertação de mestrado trata da aplicação de Estimadores Algébricos em sistemas de controle como alternativa ao uso de observadores. Devido à dificuldade de obtenção de resultados teóricos, dificuldade essa oriunda da natureza complexa dos estimadores algébricos, o trabalho é desenvolvido através do estudo de casos. Considera-se que a topologia de controle é a união de uma técnica tradicional de controle (por exemplo, uma realimentação de estado ou o método do torque calculado) com a estimação algébrica. Os resultados obtidos defendem a idéia de que os Estimadores Algébricos, quando usados como estimadores de estado, permitem obter um desempenho e uma robustez que se aproxima muito do desempenho e a robustez da mesma lei de controle no caso em que o estado é perfeitamente conhecido.; The control topology that is considered in this work is the union of a traditional control technique (e.g. a state feedback or the computed torque method) with the Algebraic Estimator. The obtained results reinforce the common sense about this class of estimators, that the use of Algebraic Estimators may produce the performance, robustness and noise immunity that mimics the case where perfect information of the state is available.

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## Invariance for Impulsive Control Systems

Fonte: Universidade Estadual Paulista
Publicador: Universidade Estadual Paulista

Tipo: Conferência ou Objeto de Conferência
Formato: 5174-5179

ENG

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75.84%

#Aerospace navigation#Hybrid systems#Impulsive control systems#Air navigation#Functions#Graph theory#Renewable energy resources#Robustness (control systems)#Vectors#Control systems

In this article, we provide invariance conditions for control systems whose dynamics are given by measure driven differential inclusions. The solution concept plays a critical role in the extension of the conventional conditions for the impulsive control context. A couple of examples illustrating the specific features of impulsive control systems are included.

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## Defects location in power systems components through a dedicated genetic algorithm

Fonte: Universidade Estadual Paulista
Publicador: Universidade Estadual Paulista

Tipo: Conferência ou Objeto de Conferência
Formato: 57-62

ENG

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55.91%

#Genetic algorithms#Power systems protection#Defects#Electric fault location#Electric relays#Electric utilities#Linear programming#Problem solving#Robustness (control systems)#Alarm messages#Binary linear programming (BLP)

In this work the problem of defects location in power systems is formulated through a binary linear programming (BLP) model based on alarms historical database of control and protection devices from the system control center, sets theory of minimal coverage (AI) and protection philosophy adopted by the electric utility. In this model, circuit breaker operations are compared to their expected states in a strictly mathematical manner. For solving this BLP problem, which presents a great number of decision variables, a dedicated Genetic Algorithm (GA), is proposed. Control parameters of the GA, such as crossing over and mutation rates, population size, iterations number and population diversification, are calibrated in order to obtain efficiency and robustness. Results for a test system found in literature, are presented and discussed. © 2004 IEEE.

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## Linear quadratic Gaussian control of discrete-time Markov jump linear systems with horizon defined by stopping times

Fonte: Universidade Estadual Paulista
Publicador: Universidade Estadual Paulista

Tipo: Conferência ou Objeto de Conferência
Formato: 25-30

ENG

Relevância na Pesquisa

55.84%

#Markov models#State and output feedback control#Stopping times#Algebraic Riccati equations#Constructive methods#Control gains#Coupled set#Discrete-time#Dynamic output feedback#Failure events#Linear quadratic Gaussian control

The linear quadratic Gaussian control of discrete-time Markov jump linear systems is addressed in this paper, first for state feedback, and also for dynamic output feedback using state estimation. in the model studied, the problem horizon is defined by a stopping time τ which represents either, the occurrence of a fix number N of failures or repairs (T N), or the occurrence of a crucial failure event (τ δ), after which the system paralyzed. From the constructive method used here a separation principle holds, and the solutions are given in terms of a Kalman filter and a state feedback sequence of controls. The control gains are obtained by recursions from a set of algebraic Riccati equations for the former case or by a coupled set of algebraic Riccati equation for the latter case. Copyright © 2005 IFAC.

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## 16.31 Feedback Control Systems, Fall 2001; Feedback Control Systems

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

EN-US

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55.84%

#feedback control#feedback control system#state-space#controllability#observability#transfer functions#canonical forms#controllers#pole-placement#optimal control#Kalman filter

Introduction to the state-space approach to control system analysis and control synthesis. State-space representation of dynamic systems; controllability and observability; state-space realizations of transfer functions; and canonical forms. Design of controllers using state-space methods, including pole placement and optimal control methods. Introduction to the Kalman filter. Limitations on performance of control systems from classical and state-space perspectives. Introduction to robustness of multivariable control systems, using frequency domain techniques. From the course home page: Course Description The goal of this subject is to teach the fundamentals of control design and analysis using state-space methods. This includes both the practical and theoretical aspects of the topic. By the end of the course, students should be able to design controllers using state-space methods and evaluate whether these controllers are "robust," that is, if they are likely to work well in practice.

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## Impulsive Synchronization of Chaotic Lur'e Systems by Linear Static Measurement Feedback: An LMI Approach

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

55.8%

#Keywords: Chaos theory#Feedback linearization#Linear matrix inequalities#Robustness (control systems)#State feedback#Synchronization#System stability#Global asymptotic synchronization#Linear static output feedback impulsive control#Lur'e systems#Neural ne Chaos

In this brief, we consider impulsive control for master-slave synchronization schemes that consist of identical chaotic Lur'e systems. Impulsive control laws are investigated which make use of linear static measurement feedback, instead of full state feed

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## The use of qualitative indicators for performance measurement in manufacturing control systems

Fonte: Instituto Politécnico de Bragança
Publicador: Instituto Politécnico de Bragança

Tipo: Conferência ou Objeto de Conferência

ENG

Relevância na Pesquisa

65.81%

New manufacturing control paradigms are being developed to improve the ability of enterprises to respond to change. However, there are no agreed definitions and methodologies for the evaluation and comparison of achievements of different manufacturing control systems approaches, making also difficult the communication and cooperation between manufacturing control systems developers. In this paper some qualitative performance indicators are identified and defined - re-configurability, robustness and agility - and methodologies for their evaluation are suggested.

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## On Robust Stability of Multivariable Interval Control Systems

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Publicado em 16/02/2005

Relevância na Pesquisa

55.91%

This paper studies robustness of MIMO control systems with parametric
uncertainties, and establishes a lower dimensional robust stability criterion.
For control systems with interval transfer matrices, we identify the minimal
testing set whose stability can guarantee the stability of the entire uncertain
set. Our results improve the results in the literature, and provide a
constructive solution to the robustness of a family of MIMO control systems.

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## Computational Analysis of Control Systems Using Dynamic Optimization

Fonte: Universidade Cornell
Publicador: Universidade Cornell

Tipo: Artigo de Revista Científica

Relevância na Pesquisa

55.8%

Several concepts on the measure of observability, reachability, and
robustness are defined and illustrated for both linear and nonlinear control
systems. Defined by using computational dynamic optimization, these concepts
are applicable to a wide spectrum of problems. Some questions addressed include
the observability based on user-information, the determination of strong
observability vs. weak observability, partial observability of complex systems,
the computation of $L^2$-gain for nonlinear control systems, and the measure of
reachability in the presence of state constraints. Examples on dynamic systems
defined by both ordinary and partial differential equations are shown.; Comment: 31 pages, 10 figures

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

Fonte: Elsevier
Publicador: Elsevier

Tipo: Artigo de Revista Científica

Relevância na Pesquisa

55.84%

#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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## Robust Hybrid Control from a Behavioural Perspective

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

Tipo: Conference paper

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66.04%

#Keywords: Actuators#Closed loop control systems#Discrete time control systems#Finite automata#Reliability#Robustness (control systems)#SCADA systems#Theorem proving#Uncertain systems#Behavioural systems theory#Hybrid control system

This paper investigates the synthesis of discrete supervisors for hybrid systems where the control objective is to enforce a language inclusion specification in the presence of plant uncertainty. The discussion is set within Willems' behavioural system theory, where we find a relationship between robustness of closed-loop performance and earlier results on abstraction based synthesis. From this relationship, we develop our main result: a method for the synthesis of robust supervisory controllers. Note that virtually any engineering system must possess some amount of robustness in order to fulfil even minimal reliability requirements. This commonly accepted fact is of a particular importance for hybrid control systems, since the motivating application areas are safety-critical and high-confidence systems as air traffic control or medical instrumentation.

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## Robust H∞ Control of Singular Impulsive Systems With Uncertain Perturbations

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

55.96%

#Keywords: Closed loop control systems#Computer simulation#Control system synthesis#Feedback control#Linear control systems#Perturbation techniques#Riccati equations#Robustness (control systems)#State feedback#Theorem proving#Uncertain systems

This paper discusses the problem of robust H∞ control for singular impulsive uncertain systems. Some new fundamental properties of singular systems with impulse effect are derived. Based on the Riccati inequality approach, sufficient conditions for robu

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## On Vinnicombe Metrics and the Stability Robustness of Linear Time-varying Systems

Tipo: Conference paper

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55.96%

#Keywords: Approximation theory#Boundary value problems#Constraint theory#Control equipment#Error analysis#Feedback control#Integral equations#Linearization#Perturbation techniques#Quadratic programming#Robustness (control systems)

We present two novel approaches for obtaining stability robustness information about linear time-invariant systems with norm-bounded time-varying output multiplicative perturbations using Vinnicombe metrics. First, a time-varying Vinnicombe metric approximation between a nominal linear time-invariant system and the perturbed linear time-varying system is developed, and we show that a calculable tight upper bound may be placed on the approximation for a subclass of small, periodic output multiplicative errors. Second, we show that a worst-case time-invariant Vinnicombe metric may be used to obtain stability robustness information about the perturbed time-varying system.

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## A Joint Space Formulation for Compliant Motion Control of Robot Manipulators

Tipo: Conference paper

Relevância na Pesquisa

55.89%

#Keywords: Closed loop control systems#Computer simulation#Force control#Manipulators#Robots#Robustness (control systems)#Closed-loop dynamics#Compliant motion control#Joint space#Projectors#Robot manipulators

This paper presents a joint space formulation for robot manipulator's hybrid motion/force control. The motivations come from 1) extending the previous work to general (either constrained or redundant) robots; and 2) improving the robustness against disturbances originated at the joint level. Contact geometry and closed-loop dynamics will be derived in this paper, also a joint space hybrid control scheme will be proposed. At the end, we show some simulation results to verify the applicability of our theory on a constrained (4-degree-of-freedom) robot WAM.

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## A Stability Robustness Test for Systems with Linear Time-varying Uncertainties

Tipo: Conference paper

Relevância na Pesquisa

55.94%

#Keywords: Mathematical models#Robustness (control systems)#Time varying systems#Uncertain systems#Linear time-varying uncertainties#Stability robustness test#Uncertainty models#System stability

In this paper, a novel stability robustness test for systems with linear time-varying uncertainties is introduced. The advantages of the stability robustness test lie in the fact that it can cope with multi-input multi-output, stable, or unstable systems

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## Pure 2D Visual Servo control for a class of under-actuated dynamic systems

Tipo: Conference paper

Relevância na Pesquisa

55.82%

#Keywords: Algorithms#Error analysis#Feedback control#Helicopters#Kinematics#Matrix algebra#Mobile telecommunication systems#Nonlinear control systems#Perturbation techniques#Robustness (control systems)#Unmanned vehicles

A pure image-based strategy for visual servo control of a class of dynamic systems is proposed. The proposed design concerns the dynamics of unmanned aerial vehicles capable of quasi-stationary flight (hover and near hover flight). The visual servo control task considered is to locate the camera relative to a stationary target. The paper extends earlier work, by weakening the assumption on the construction of the visual error used. In prior work some inertial information was used in the error construction to guarantee the passivity properties of the control design. In this paper the visual error is defined purely in terms of the 2D image features derived from the camera signal.

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## Model Validation for Control and Controller Validation in a Prediction error Identification Framework - Part I

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

Tipo: Artigo de Revista Científica

Relevância na Pesquisa

55.84%

#Keywords: Control equipment#Error analysis#Identification (control systems)#Predictive control systems#Robustness (control systems)#Transfer functions#Error identification#Control system analysis Controller validation#Identification for robust control#Model validation#System identification

We propose a model validation procedure that consists of a prediction error identification experiment with a full order model. It delivers a parametric uncertainty ellipsoid and a corresponding set of parameterized transfer functions, which we call prediction error (PE) uncertainty set. Such uncertainty set differs from the classical uncertainty descriptions used in robust control analysis and design. We develop a robust control analysis theory for such uncertainty sets, which covers two distinct aspects: (1) Controller validation. We present necessary and sufficient conditions for a specific controller to stabilize - or to achieve a given level of performance with - all systems in such PE uncertainty set. (2) Model validation for robust control. We present a measure for the size of such PE uncertainty set that is directly connected to the size of a set controllers that stabilize all systems in the model uncertainty set. This allows us to establish that one uncertainty set is better tuned for robust control design than another, leading to control-oriented validation objectives.

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## Adaptive Control of a Class of Slowly Time Varying Systems With Modeling Uncertainties

Tipo: Artigo de Revista Científica

Relevância na Pesquisa

56.05%

#Keywords: Computer simulation#Control nonlinearities#Control system synthesis#Eigenvalues and eigenfunctions#Linear control systems#Mathematical models#Matrix algebra#Robustness (control systems)#System stability#Time varying control systems#Uncertain sys Backstepping

In a recent work, a new linear adaptive controller based on certainty-equivalence and backstepping design, which promises a level of transient and asymptotic performance comparable to that of the tuning functions adaptive backstepping controller without using high order nonlinearities, was proposed for linear time invariant systems. The proposal was supplemented with robustness and performance analysis in the presence of modeling uncertainties. In this note, the same idea is used to develop a new linear adaptive controller for slowly time varying systems with modeling uncertainties. The new adaptive control scheme guarantees robustness with respect to modeling errors via normalizing damping, parameter projection, and static normalization. Use of normalizing damping is essential in protecting the "linearity" of the system, which plays a key role in reaching the stability and robustness results.

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## A Combined Application of H ∞ Loop Shaping and μ - Synthesis to Control High-Speed Flywheels

Tipo: Artigo de Revista Científica

Relevância na Pesquisa

55.99%

#Keywords: Closed loop control systems#Computational complexity#Computer simulation#Control system synthesis#Flywheels#Magnetic bearings#Mathematical models#Matrix algebra#Robustness (control systems)#Rotors#Speed control

The development of robust controllers for high-speed flywheel rotors supported on active magnetic bearings (AMBs) has been extensively studied over the past decade. Such flywheels can be used as energy momentum wheels (EMWs) onboard spacecraft, and pose a challenging control problem due to their high flexibility, nontrivial parametric uncertainty, and rotor-speed dependence. A combined H∞ loop shaping and μ-synthesis approach is used in this paper to design controllers for EMWs supported on AMBs. This combination between these two well-established control methodologies is novel to the design of robust controllers for such systems. H∞ loop shaping guarantees (through the specification of loop-shaping weights) closed-loop performance and robustness to generic unstructured coprime factor uncertainty, whereas robustness to highly directional parametric uncertainty is incorporated through a μ-synthesis design. Furthermore, in order to reduce the computational complexity of the control design and the order of the synthesized controllers, a method is proposed in this paper to reduce the number of states that depend on the rotor speed. The proposed methodology is demonstrated through numerical simulations and experimental results.

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## l ∞ -Bounded Robustness for Nonlinear Systems: Analysis and Synthesis

Tipo: Artigo de Revista Científica

Relevância na Pesquisa

55.96%

#Keywords: Approximation theory#Closed loop control systems#Control equipment#Dynamic programming#Nonlinear control systems#Optimal control systems#Spurious signal noise#Dissipative systems#Robustness (control systems) Controller synthesis#Dissipative systems#Dynamic programming

The purpose of this paper is to describe systematic analysis and design tools for robust control problems with l∞ criteria. We first generalize the Hill-Moylan-Willems framework for dissipative systems to accommodate l∞ criteria, and then derive state

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