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Controle por modos deslizantes aplicado a sistema de posicionamento dinâmico.; Sliding mode control applied to dynamic positioning systems.

Agostinho, Adriana Cavalcante
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 20/05/2009 PT
Relevância na Pesquisa
55.74%
Este trabalho apresenta a aplicação da teoria de controle robusto não linear por modos deslizantes a sistemas de posicionamento dinâmico para embarcações flutuantes, com validação experimental. O objetivo do sistema de controle projetado é manter a embarcação próxima a uma posição pré-ajustada (set-point) ou a uma trajetória preestabelecida (pathfollowing), por meio das forças geradas nos propulsores, mesmo estando o sistema na presença de distúrbios externos, ou seja, vento, ondas e correnteza. A princípio, realizaram-se simulações numéricas com o sistema projetado a fim de verificar o seu desempenho. O simulador utilizado foi implementado em ambiente Matlab/Simulink, considerando a dinâmica da embarcação e dos agentes ambientais. As simulações consistiram de manobras realizadas em condições nominais e na ausência de esforços ambientais, com embarcação cheia (plena) e vazia (lastro). Para validação do algoritmo implementado realizaram-se ensaios de manobra em condição de calmaria e na presença de vento, com a embarcação em plena carga e vazia. Os ensaios foram administrados no laboratório do Departamento de Engenharia Naval e Oceânica da USP (DENO). O algoritmo de controle por modos deslizantes demonstrou-se robusto a variações de condições ambientais (vento)...

Controle não linear aplicado a malhas de controle com válvulas de alto atrito.; Nonlinear control applied to control loops with high friction valves.

Baeza, João Rostaizer
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 18/02/2013 PT
Relevância na Pesquisa
55.81%
As válvulas de controle são elementos finais muito importantes na indústria de processos, pois são as responsáveis por controlar a pressão em dutos ou vazão dos fluidos de processo, impactando diretamente na qualidade do produto final. Por serem elementos mecânicos móveis estão sujeitas ao atrito, uma não linearidade que quando excessiva, pode causar oscilações e erros na abertura da válvula. A presença de oscilações nas malhas de controle aumenta a variabilidade das variáveis de processo, o desgaste dos componentes e o consumo de energia, além de provocar o desperdício de materiais. O desenvolvimento de novas técnicas de compensação de atrito é fundamental para melhorar o desempenho das malhas de controle, sendo, portanto, de grande interesse para a indústria de processos industriais. Este trabalho apresenta o estudo de cinco compensadores não lineares: controlador rastreador de trajetória, controlador por modos deslizantes, controlador por modos deslizantes integrador, controlador por modelo interno não linear e controlador PI não linear, os quais são desenvolvidos desde a teoria à implementação prática em uma válvula de controle real. Os resultados obtidos, mostram que os controladores projetados apresentaram desempenho bastante satisfatórios...

Optimal linear and nonlinear control design for chaotic systems

Rafikov, Marat; Balthazar, José Manoel
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Conferência ou Objeto de Conferência Formato: 867-873
ENG
Relevância na Pesquisa
65.89%
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.

Desenvolvimento e análise de controle híbrido preditivo por lógica fuzzy de processos de polimerização; Development and analysis of predictive hybrid control by fuzzy logic for polymerization processes

Nádson Murilo Nascimento Lima
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 13/12/2010 PT
Relevância na Pesquisa
55.82%
A síntese de controladores representa uma importante vertente dos desenvolvimentos atuais no campo da pesquisa acadêmica e industrial. Um controlador bem projetado pode significar sucesso no que se refere aos objetivos de produção, sendo gerados materiais com as especificações desejadas e proporcionando que o sistema opere sob certas restrições, levando em consideração aspectos relativos à operabilidade, segurança e minimização de resíduos. Para tanto, sabe-se que as etapas de modelagem são fundamentais para a delineação de estratégias de controle. Contudo, a obtenção de representações matemáticas precisas e, ao mesmo tempo, aplicáveis para o controle da maioria dos processos de interesse da engenharia química é uma tarefa árdua, devido à presença de comportamentos dinâmicos não lineares e variantes ao longo do tempo e, por vezes, do espaço. Deste modo, busca-se a obtenção de modelos mais simples, porém dotados da imprescindível representatividade inerente aos sistemas de produção, a fim de serem projetadas estruturas de controle adequadas para cada necessidade específica. Esta tese enfoca o desenvolvimento de quatro controladores avançados híbridos preditivos não lineares multivariáveis...

Técnicas não lineares de controle e filtragem aplicadas ao problema de rastreamento de trajetórias de robôs móveis com deslizamento longitudinal das rodas; Nonlinear techniques of control and filtering applied to the trajectory tracking problem of mobile robots with longitudinal wheel slip

Juliano Gonçalves Iossaqui
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Formato: application/pdf
Publicado em 28/02/2013 PT
Relevância na Pesquisa
65.86%
Esta tese trata do problema de controle de trajetórias de robôs móveis não holonômicos com deslizamento longitudinal das rodas. As estratégias de controle propostas são projetadas usando dois modelos, um cinemático e um dinâmico, que consideram os deslizamentos longitudinais das rodas como parâmetros desconhecidos. A primeira estratégia de controle consiste em um controlador adaptativo projetado com base em um modelo cinemático que utiliza como entrada de controle, as velocidades angulares das rodas. Essas velocidades angulares são fornecidas por uma lei de controle cinemática que utiliza estimativa dos parâmetros de deslizamento desconhecidos, obtidas por meio de uma lei de adaptação. A segunda estratégia de controle consiste em um controlador adaptativo projetado com base em um modelo dinâmico simplificado que utilizam como entrada de controle, forças de propulsão aplicadas no centro das rodas. A lei de controle, que fornece essas forças, é projetada aplicando-se a técnica backstepping ao modelo dinâmico reduzido, que foi obtido com a utilização do método da dinâmica inversa. Os parâmetros de deslizamento longitudinal desconhecidos, necessários para a utilização do método da dinâmica inversa, são estimados por uma lei de adaptação. O filtro de Kalman unscented também é utilizado para estimar os parâmetros de deslizamento desconhecidos. Essas estimativas são utilizadas...

Sensor locations and noise reduction in high-purity batch distillation control loops

Oisiovici,R.M.; Cruz,S.L.
Fonte: Brazilian Society of Chemical Engineering Publicador: Brazilian Society of Chemical Engineering
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2000 EN
Relevância na Pesquisa
65.7%
The influence of the sensor locations on the composition control of high-purity batch distillation columns has been investigated. Using concepts of the nonlinear control theory, an input-output linearizing controller was implemented to keep the distillate composition constant at a desired value by varying the reflux ratio. An Extended Kalman Filter was developed to estimate the compositions required in the control algorithm using temperature measurements. In the presence of measurement noise, the control performance depended greatly on the sensor locations. Placing the sensors further from the top stages reduced the detrimental effects of noise but increased the inference error. To achieve accurate composition control, both noise reduction and composition estimate accuracy should be considered in the selection of the sensor locations.

Kalman Meets Neuron: The Emerging Intersection of Control Theory with Neuroscience

Schiff, Steven J.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em //2009 EN
Relevância na Pesquisa
55.77%
Since the 1950s, we have developed mature theories of modern control theory and computational neuroscience with almost no interaction between these disciplines. With the advent of computationally efficient nonlinear Kalman filtering techniques, along with improved neuroscience models that provide increasingly accurate reconstruction of dynamics in a variety of important normal and disease states in the brain, the prospects for a synergistic interaction between these fields are now strong. I show recent examples of the use of nonlinear control theory for the assimilation and control of single neuron dynamics, the modulation of oscillatory wave dynamics in brain cortex, a control framework for Parkinsonian dynamics and seizures, and the use of optimized parameter model networks to assimilate complex network data – the ‘consensus set’.

Derivation and Application of Nonlinear Analytical Redundancy Techniques with Applications to Robotics

Leuschen, Martin L.; Leuschen, Martin L.
Fonte: Universidade Rice Publicador: Universidade Rice
Tipo: Tese de Doutorado
ENG
Relevância na Pesquisa
65.87%
PhD Thesis; Derivation and Application of Nonlinear Analytical Redundancy Techniques with Applications to Robotics Fault detection is important in many robotic applications. Failures of powerful robots, high velocity robots, or robots in hazardous environments are quite capable of causing significant and possibly irreparable havoc if they are not detected promptly and appropriate action taken. As robots are commonly used because power, speed, or resistances to environmental factors need to exceed human capabilities, fault detection is a common and serious concern in the robotics arena. Analytical redundancy (AR) is a fault-detection method that allows us to explicitly derive the maximum possible number of linearly independent control model-based consistency tests for a system. Using a linear model of the system of interest, analytical redundancy exploits the null-space of the state space control observability matrix to allow the creation of a set of test residuals. These tests use sensor data histories and known control inputs to detect any deviation from the static or dynamic behaviors of the model in real time. The standard analytical redundancy fault detection technique is limited mathematically to linear systems. Since analytical redundancy is a model-based technique...

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

Ross, I. Michael; Fahroo, Fariba
Fonte: IEEE Publicador: IEEE
Tipo: Conference Paper
Relevância na Pesquisa
55.74%
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.

Pseudospectral Methods for Optimal Motion Planning of Differentially Flat Systems

Ross, I. Michael; Fahroo, Fariba
Fonte: IEEE Publicador: IEEE
Tipo: Conference Paper
Relevância na Pesquisa
65.65%
The article of record as published may be located at http://ieeexplore.ieee.org; Approved for public display, distribution unlimited; IEEE Transactions on Automatic Control, vol. 49, no. 8, August 2004 (Journal Article); This note presents some preliminary results on combining two new ideas from nonlinear control theory and dynamic optimization. We show that the computational framework facilitated by pseudospectral methods applies quite naturally and easily to Fliess implicit state variable representation of dynamical systems. The optimal motion planning problem for differentially flat systems is equivalent to a classic Bolza problem of the calculus of variations. In this note, we exploit the notion that derivatives of flat outputs given in terms of Lagrange polynomials at Legendre'Gauss'Lobatto points can be quickly computed using pseudospectral differentiation matrices. Additionally, the Legendre pseudospectral method approximates integrals by Gauss-type quadrature rules. The application of this method to the two-dimensional crane model reveals how differential flatness may be readily exploited.

Obstructions to Motion Planning by the Continuation Method

Amiss, David Scott Cameron
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado
EN; EN
Relevância na Pesquisa
55.81%
The subject of this thesis is the motion planning algorithm known as the continuation method. To solve motion planning problems, the continuation method proceeds by lifting curves in state space to curves in control space; the lifted curves are the solutions of special initial value problems called path-lifting equations. To validate this procedure, three distinct obstructions must be overcome. The first obstruction is that the endpoint maps of the control system under study must be twice continuously differentiable. By extending a result of A. Margheri, we show that this differentiability property is satisfied by an inclusive class of time-varying fully nonlinear control systems. The second obstruction is the existence of singular controls, which are simply the singular points of a fixed endpoint map. Rather than attempting to completely characterize such controls, we demonstrate how to isolate control systems for which no controls are singular. To this end, we build on the work of S. A. Vakhrameev to obtain a necessary and sufficient condition. In particular, this result accommodates time-varying fully nonlinear control systems. The final obstruction is that the solutions of path-lifting equations may not exist globally. To study this problem...

Análisis no lineal de sistemas de control de nivel con algoritmo exponencial polinómico

Posada Jaramillo, Ricardo; Navarro Betancur, Guillermo Adolfo
Fonte: Universidad EAFIT; Maestría en Matemáticas Aplicadas; Escuela de Ciencias y Humanidades. Departamento de Ciencias Básicas Publicador: Universidad EAFIT; Maestría en Matemáticas Aplicadas; Escuela de Ciencias y Humanidades. Departamento de Ciencias Básicas
Tipo: masterThesis; Tesis de Maestría; acceptedVersion
SPA
Relevância na Pesquisa
55.76%
El objetivo de este trabajo es el análisis de las características no lineales en un sistema de control de nivel mediante el algoritmo exponencial polinómico propuesto por J. P. Shunta. El nivel del fluido en el recipiente -el cual está manipulado por una válvula- debe mantenerse en un valor promedio determinado -- De acuerdo con los medios utilizados, el trabajo fue del tipo documental y computacional. Se aplicaron definiciones y teoremas del análisis matemático y de la teoría de control no lineal. Con esta información se mostró que el sistema tiene un único punto de equilibrio local asintóticamente estable tipo espiral o nodo, no tiene ciclos límite, ni tiempo de escape finito, ni puntos de bifurcación, ni caos. Las simulaciones realizadas en Simulink de MatLab® y en pplane7® corroboraron estos resultados teóricos. También se encontró una función de Lyapunov y comprobar que el sistema es localmente estable entrada estado -- Mediante simulaciones también se hicieron pruebas de robustez al sistema, bajo la influencia de ruido blanco, usando cuatro controladores: el proporcional, el de error cuadrático, el exponencial polinómico y el proporcional integral derivativo. Estas pruebas se hicieron tanto con perturbación como sin ella...

Uniformly hyperbolic control theory

Kawan, Christoph
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 25/11/2015
Relevância na Pesquisa
55.73%
This paper gives a summary of a body of work at the intersection of control theory and smooth nonlinear dynamics. The main idea is to transfer the concept of uniform hyperbolicity, central to the theory of smooth dynamical systems, to control-affine systems. Combining the strength of geometric control theory and the hyperbolic theory of dynamical systems, it is possible to deduce control-theoretic results of non-local nature that reveal remarkable analogies to the classical hyperbolic theory of dynamical systems.

Robust Adaptive Dynamic Programming for Optimal Nonlinear Control Design

Jiang, Yu; Jiang, Zhong-Ping
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 09/03/2013
Relevância na Pesquisa
55.82%
This paper studies the robust optimal control design for uncertain nonlinear systems from a perspective of robust adaptive dynamic programming (robust-ADP). The objective is to fill up a gap in the past literature of ADP where dynamic uncertainties or unmodeled dynamics are not addressed. A key strategy is to integrate tools from modern nonlinear control theory, such as the robust redesign and the backstepping techniques as well as the nonlinear small-gain theorem, with the theory of ADP. The proposed robust-ADP methodology can be viewed as a natural extension of ADP to uncertain nonlinear systems. A practical learning algorithm is developed in this paper, and has been applied to a sensorimotor control problem.; Comment: 8 pages, 4 figures

Balanced Reduction of Nonlinear Control Systems in Reproducing Kernel Hilbert Space

Bouvrie, Jake; Hamzi, Boumediene
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 12/11/2010
Relevância na Pesquisa
55.73%
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.

Control of Vibratory Energy Harvesters in the Presence of Nonlinearities and Power-Flow Constraints

Cassidy, Ian Lerner
Fonte: Universidade Duke Publicador: Universidade Duke
Tipo: Dissertação
Publicado em //2012
Relevância na Pesquisa
55.78%

Over the past decade, a significant amount of research activity has been devoted to developing electromechanical systems that can convert ambient mechanical vibrations into usable electric power. Such systems, referred to as vibratory energy harvesters, have a number of useful of applications, ranging in scale from self-powered wireless sensors for structural health monitoring in bridges and buildings to energy harvesting from ocean waves. One of the most challenging aspects of this technology concerns the efficient extraction and transmission of power from transducer to storage. Maximizing the rate of power extraction from vibratory energy harvesters is further complicated by the stochastic nature of the disturbance. The primary purpose of this dissertation is to develop feedback control algorithms which optimize the average power generated from stochastically-excited vibratory energy harvesters.

This dissertation will illustrate the performance of various controllers using two vibratory energy harvesting systems: an electromagnetic transducer embedded within a flexible structure, and a piezoelectric bimorph cantilever beam. Compared with piezoelectric systems, large-scale electromagnetic systems have received much less attention in the literature despite their ability to generate power at the watt--kilowatt scale. Motivated by this observation...

Streamlining of the state-dependent Riccati equation controller algorithm for an embedded implementation

Katsev, Sergey
Fonte: Rochester Instituto de Tecnologia Publicador: Rochester Instituto de Tecnologia
Tipo: Tese de Doutorado
EN_US
Relevância na Pesquisa
55.79%
In many practical control problems the dynamics of the plant to be controlled are nonlinear. However, in most cases the controller design is based on a linear approximation of the dynamics. One of the reasons for this is that, in general, nonlinear control design methods are difficult to apply to practical problems. The State Dependent Riccati Equation (SDRE) control approach is a relatively new practical approach to nonlinear control that has the simplicity of the classical Linear Quadratic control method. This approach has been recently applied to control experimental autonomous air vehicles with relative success. To make the SDRE approach practical in applications where the computational resources are limited and where the dynamic models are more complex it would be necessary to re-examine and streamline this control algorithm. The main objective of this work is to identify improvements that can be made to the implementation of the SDRE algorithm to improve its performance. This is accomplished by analyzing the structure of the algorithm and the underlying functions used to implement it. At the core of the SDRE algorithm is the solution, in real time, of an Algebraic Riccati Equation. The impact of the selection of a suitable algorithm to solve the Riccati Equation is analyzed. Three different algorithms were studied. Experimental results indicate that the Kleinman algorithm performs better than two other algorithms based on Newton’s method. This work also demonstrates that appropriately setting a maximum number of iterations for the Kleinman approach can improve the overall system performance without degrading accuracy significantly. Finally...

Optimal economic planning and control for the management of ecosystems

Macksamie, Kevin
Fonte: Rochester Instituto de Tecnologia Publicador: Rochester Instituto de Tecnologia
Tipo: Tese de Doutorado
EN_US
Relevância na Pesquisa
55.8%
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)...

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

De Bruyne, Franky; Anderson, Brian; Landau, I D
Fonte: Pergamon-Elsevier Ltd Publicador: Pergamon-Elsevier Ltd
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
55.78%
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.

Nonlinear H∞ control of an experimental pH neutralization system

Longhi,L. G. S.; Lima,E. L.; Barrera,P. R.; Secchi,A. R.
Fonte: Latin American applied research Publicador: Latin American applied research
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/07/2004 EN
Relevância na Pesquisa
55.89%
The classical control theory is based on the design of linear controllers for systems described by linear models. However, there exist some situations where it is not recommended, or even impossible, to use a linear controller. One of those situations arises when the magnitude of the process gain experiences a dramatic variation within the operating range of interest. A classic example of a chemical process where this situation occurs is the pH control around the neutralization point in a continuous stirred tank. In this work, the pH control for a strong acid - strong base system is addressed. To solve this problem, a nonlinear H∞ control law is derived based on a nonlinear model previously developed. The attainment of that control law is done with the help of recent mathematical results from the authors concerning the solution of Hamilton-Jacobi-Isaacs inequalities. The nonlinear controller is implemented on an experimental reactor and its performance is compared with a PID control law tuned according to the classical minimum error integral criteria. The obtained results show that the nonlinear H∞ control theory can be a good alternative to solve this difficult SISO (Single Input - Single Output) control problem.