Orientador: Juan Francisco Camino dos Santos / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-22T20:54:00Z (GMT). No. of bitstreams: 1 Iossaqui_JulianoGoncalves_D.pdf: 6240978 bytes, checksum: 597b8a76b18670b60a9c6b9804b7b692 (MD5) Previous issue date: 2013 / Resumo: 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, da mesma forma que as estimativas obtidas pela lei de adaptação, nas leis que fornecem as velocidades angulares e as forças de propulsão das rodas. As estratégias propostas, baseadas na teoria de controle adaptativo e na teoria de filtragem, diferenciam-se basicamente pela técnica que utilizam para estimar os parâmetros de deslizamento. No caso das estratégias adaptativas, a estabilidade do sistema em malha fechada é garantida pela teoria de Lyapunov. Simulações numéricas são realizadas para apresentar o desempenho das estratégias de controle propostas em termos do erro de postura do robô para diferentes perfis de deslizamento / Abstract: This thesis deals with the trajectory tracking control problem of nonholonomic mobile robots with longitudinal slip of the wheels. The proposed control strategies are designed using a kinematic model and a dynamic model which consider the longitudinal slip of the wheels as unknown parameters. The first proposed control strategy consists in an adaptive controller based on a kinematic model that uses the wheel angular velocities as control input. These angular velocities are provided by a kinematic control law which uses the unknown slip parameters estimated by an adaptive rule. The second proposed control strategy consists in an adaptive controller based on a simplified dynamic model that uses the thrust forces applied on the center of the wheels as control input. The control law that provides these thrust forces is designed using the backstepping technique applied to a reduced dynamic model obtained using the inverse dynamic method. The unknown longitudinal slip parameters necessary to use the inverse dynamic method are estimated by an adaptation rule. The unscented Kalman filter is also used to estimate the unknown slip parameters. These estimates are used, in the same way as the estimates obtained by the adaptation rule, by the control laws that provide the angular velocities and the thrust forces. The main difference between the proposed control strategies, based on the adaptive control theory and on the filtering theory, is given by the technique used to estimate the slip parameters. In the case of the adaptive strategies, the stability of the closed-loop system is ensured by the Lyapunov theory. Numerical simulations show the performance of the proposed control strategies in terms of the posture error of the robot with different wheels slip profiles / Doutorado

Orientador: José Maria Campos dos Santos / Dissertação (mestrado profissional) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-19T06:05:00Z (GMT). No. of bitstreams: 1 Sica_MauricioRoselli_M.pdf: 6187406 bytes, checksum: eb76c3ee4e60cfc7e2fbff17dbb0b05b (MD5) Previous issue date: 2011 / Resumo: As simulações físicas em laboratórios da indústria automotiva são realizadas utilizando informações colhidas de veículos que são submetidos a ciclos de testes em rotas urbanas. Medir as respostas em pontos específicos durante uma rota de teste, não significa conhecer as excitações a que o veículo esta sendo submetido, visto que este normalmente é composto por sistemas mecânicos não lineares. O objetivo deste trabalho é desenvolver um algoritmo que possibilite através dos dados de resposta medidos em campo, conhecer as excitações de entrada, contribuindo para a reprodução da rota de teste. A metodologia utilizada está baseada na obtenção de funções de resposta em freqüência, de modelos lineares simples e no desenvolvimento de sinais de entrada, capazes de reproduzir as mesmas respostas medidas nas rotas nos sistemas não lineares. O algoritmo desenvolvido foi avaliado com simulações em sistemas lineares e não lineares de um, dois e quatro graus de liberdade. Através dos sinais de resposta medidos em um sistema e, utilizando sinal de identificação tipo Schroeder, foi possível estimar as forças de excitação, com um erro menor do que 1,0% para sistemas de dois graus de liberdade lineares e não lineares. No caso de sistemas com quatro graus de liberdade este valor foi menor do que 1,5%, utilizando sinais de identificação do tipo multisseno. Discute-se a metodologia utilizada para a obtenção das funções de resposta em freqüência comparando-a com outras empregadas em equipamentos comerciais, bem como a influência de fatores no processo de convergência do algoritmo, como o grau de não linearidade, a qualidade do sinal medido e a importância da escolha do sinal para a identificação dos sistemas / Abstract: Laboratory simulation testing in the automotive industry is carried out considering information acquired from vehicle urban routes testing. Due to the non-linearity of the vehicle mechanical systems, the output measuring collected from routes on specific points, does not mean the knowledge of the input signal excitation which it is submitted. The present study focuses on the development of an iterative algorithm that knowing the output signals measured, it is able to search for the input excitations, so given subsidies to reproduce events of the urban route, with its load amplitude and its frequencies. The methodology is based on the frequency response function of simple linear models and on the development of input signal, which is capable to reproduce the same measured responses of non-linear system. The developed algorithm was validated with simulations on linear and non linear system with one, two and four degrees of freedom. Making use of the Schroeder identification signal, it was possible to estimate input forces with an error lower than 1,0%, for linear and non-linear systems with two degrees of freedom. In the case of four degrees of freedom the algorithm converges to estimate input force with a tolerance of error lower than 1,5%, using multissine identification signal. A discussion about the methodology used to obtain the frequency function response is carried out, comparing it with others found in commercial test equipments, as well the influence of some factors on the algorithm process of convergence, as the level of the non-linearity of the system, the quality of the acquisition of signal response and the importance of the correct choice of the input signal for the system identification / Mestrado / Dinâmica / Mestre em Engenharia Automobilistica

Orientadores: Wagner Caradori do Amaral, Ricardo Jose Gabrielli Barreto Campello / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-08-04T02:57:58Z (GMT). No. of bitstreams: 1 Rosa_Alexda_M.pdf: 896715 bytes, checksum: 1baf3dbaef2a1280f09feabed84d996c (MD5) Previous issue date: 2005 / Resumo: Este trabalho analisa a modelagem de sistemas nao-lineares utilizando modelos de Wiener/Volterra com funcoes ortonormais de Kautz. Os modelos de Volterra sao uma generalizacao do modelo resposta ao impulso para a descricao de sistemas naolineares. Esses modelos necessitam de um numero consideravel de termos para a representacao dos kernels de Volterra. Essa complexidade pode ser reduzida utilizando-se uma representacao do tipo Wiener/Volterra, em que os kernels sao desenvolvidos utilizando uma base de funcoes ortonormais. Sao discutidos aspectos da selecao dos parametros livres (polos) que caracterizam essas funcoes, particularmente a selecao otima dos polos complexos das funcoes de Kautz. Este problema e resolvido minimizando-se o limitante superior do erro que surge a partir da aproximação truncada dos kernels de Volterra usando-se as funcoes de Kautz. Obtem-se a solu¸cao analitica para a escolha otima de um dos parametros relacionados com o polo de Kautz, sendo os resultados validos para modelos Wiener/Volterra de qualquer ordem. Apresentam-se ainda resultados de simulacoes que ilustram a metodologia apresentada, bem como a modelagem de um sistema de levitacao magnetica / Abstract: This work investigates the modelling of nonlinear systems using the Wiener/Volterra models with Kautz orthonormal functions. The Volterra models constitute a generalization of the impulse response model to describe nonlinear systems. Such models require a large number of terms for representing the Volterra kernels. However, this complexity can be reduced by using Wiener/Volterra models, in which the kernels are expanded using an orthonormal basis functions. Aspects about selection of the free parameters (poles) characterizing theses functions are discussed, in particular the optimal selection of the complex poles of the Kautz functions. This problem is solved by minimizing the upper bound of the error arising from the truncated approximation of Volterra kernels using Kautz functions. An analytical solution for the optimal choice of one of the parameters related to the Kautz pole is thus obtained, with the results valid for any-order Wiener/Volterra models. Simulations that illustrate the methodology described above are presented. Also, the modelling of a magnetic levitation system is discussed. / Mestrado / Engenharia / Mestre em Engenharia Elétrica

Orientador: Jose Mario Martinez / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Matematica, Estatistica e Computação Cientifica / Made available in DSpace on 2018-08-04T03:19:31Z (GMT). No. of bitstreams: 1 Francisco_JulianodeBem_D.pdf: 963435 bytes, checksum: 88cedcb7cfb40d6a63f0ce67f0abb970 (MD5) Previous issue date: 2005 / Resumo: Algoritmos robustos e numericamente viáveis para resolver problemas de otimização têm sido cada vez mais solicitados em problemas práticos que aparecem em engenharia, química, física, entre outras áreas. Com isso em mente, este trabalho apresenta um novo método globalmente convergente baseado em região de confiança para resolver sistemas não-lineares indeterminados (mais incógnitas do que equações) com restrições de caixa, podendo, portanto, ser aproveitado para a fase de viabilidade nos algoritmos baseados em restauração periódica. É mostrado que esse método apresenta, sob certas hipóteses, convergência localmente quadrática. Em uma outra parte deste trabalho é apresentado um novo algoritmo globalmente convergente, o qual se baseia em região de confiança, para resolver problemas de otimização do tipo min f(x); s:a: x 2 D; onde f : Rn ! R é assumida para ser continuamente diferenciável e D C Rn, um subconjunto fechado arbitrário. Em vez de considerar a região de confiança explicitamente nos subproblemas, esse método introduz um parâmetro de regularização que busca imitar a região de confiança. Com essa caracterização, os subproblemas consistem em minimizar um modelo quadratico de f sujeito ao subconjunto D. Uma importante aplicação desse novo algoritmo aparece em química quântica e resultará em um novo algoritmo globalmente convergente, robusto e numericamente viável para calcular estruturas eletrônicas de átomos e moléculas / Abstract: Abstract Robust and numerically feasible algorithms for solving optimization problems have been demanded for solving practice problems that appear in Engineering, Chemistry, Physics and others. This work present a new globally convergent method based on trust regions for solving box-constrained underdetermined nonlinear systems (more unknowns than equations), that can be used on the feasibility fase of algorithms based on periodic restoration. Under some assumptions, it will be proved locally quadratic convergence. In other part of this work, a new globally convergent algorithm is introduced, based on trust regions, for solving the optimization problem min f(x); s:t: x 2 D; where f : Rn ! R is continuously dierentiable and D C Rn is an arbitrary closed subset. Instead of considering explicitly the trust region on the subproblems, the method introduces a regularization parameter that mimics the trust region. With this characterization, the subproblems consist on minimizing a quadratic model of f subject to D. numerically feasible globally convergent algorithm for electronic structure calculations is obtained. / Doutorado / Matematica Aplicada / Doutor em Matemática Aplicada

Submitted in fulfillment of the requirements for the Doctors Degree in Engineering (Electrical Engineering: Light Current), Durban University of Technology, Durban, South Africa, 2017. / Controller performance assessment (CPA) is concerned with the design of analytical tools that are utilized to evaluate the performance of process control loops. The objective of the CPA is to ensure that control systems operate at their full potential, and also to indicate when a controller design is performing unsatisfactorily under current closed loop conditions. Such monitoring efforts are imperative to minimize product variability, improve production rates and reduce wastage. Various studies conducted on process control loop performance indicate that as many as 60% of control loops often suffer from some kind of performance problem. It is therefore an important task to detect unsatisfactory control loop behavior and suggest remedial action. Such a monitoring system must be integrated into the control system life span as plant changes and hardware issues become apparent. CPA is well established for linear systems. However, not much research has been conducted on CPA for nonlinear systems. Traditional CPA analytical tools depend on the theoretical minimum variance control law that is derived from models of linear systems. In systems exhibiting dominant nonlinear behavior, the accuracy of linear based CPA is compromised. In light of this, there is a need to broaden existing CPA knowledge base with comprehensive benchmarking indices for the performance analysis of nonlinear process control systems. The research efforts presented in this thesis focuses on the development and analysis of such CPA tools for univariate nonlinear process control loops experiencing the negative effects of dominant nonlinearities emanating from the process. Two novel CPA frameworks are proposed; first a model based nonlinear assessment index is developed using an open loop model of the plant in an artificial neural network NARMAX (NNARMAX) representation. The nonlinear control loop is optimized offline using a proposed Nelder Mead-Particle Swarm Optimization (NM-PSO) hybrid search to determine global optimal control parameters for a gain scheduled PID controller. Application of the benchmark in real-time utilizes a synthetic process output derived from the NNARMAX system which is compared to the actual closed loop performance. In the case where no process model is available, a second method is presented. An autonomous data driven approach based on Multi-Class Support Vector Machines (MC- SVMs) is developed and analyzed. Unlike the model based method, the closed loop performance is classified according to five distinct class groups. MC-SVM classifier requires minimal process loop information other than routine operating closed loop data. Several simulation case studies conducted using MATLAB™ software package demonstrate the effectiveness of the proposed performance indices. Furthermore, the methodologies presented in this work were tested on real world systems using control loop data sets from a computer interfaced full scale pilot pH neutralization plant and pulp and paper industry. / D

Orientador: Kyoko Furuya / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb Wataghin / Made available in DSpace on 2018-08-04T01:53:26Z (GMT). No. of bitstreams: 1 SousaJunior_DelcidesFlaviode_M.pdf: 32680218 bytes, checksum: aa259799e554166260b37c235e19a803 (MD5) Previous issue date: 1998 / Resumo:Apresentamos nesta dissertação um estudo da conexão entre a Mecânica Clássica e a Mecânica Quântica através dos diagramas de energia vs. período para as principais famílias de órbitas periódicas de um dado sistema dinâmico. O diagrama quântico é definido através do espectro do sistema quântico correspondente, que mostra cicatrizes dessas famílias no regime semiclássico. Dois sistemas hamiltonianos, com dois graus de liberdade e apresentando comportamento misto ( caótico e regular ) , são estudados. O primeiro é o pêndulo elástico, usado como paradigma de caos clássico. Aspectos essenciais da sua dinâmica são estudados e o diagrama clássico de energia vs. período com as principais famílias de órbitas periódicas é construido. O segundo sistema é o Hamiltoniano Spin-Bóson, um sistema quântico para o qual trabalhos anteriores definiram um análogo clássico, para o qual estudou-se o comportamento caótico e famílias de órbitas periódicas. Uma versão quântica deste diagrama de energia vs. período é mostrada para este modelo. As duas versões são comparadas no regime de caos misto e o ajuste no limite semiclássico discutido. Uma concordância qualitativa é obtida, com indicações de que as cicatrizes são mais acentuadas nas regiões onde ocorrem bifurcações de órbitas periódicas / Abstract:We study the connection between Classical and Quantum Mechanics using the plots of Energy VS. Period for the main families of periodic orbits of certain dynamical system .The quantum E-t plot is defined through the spectrum of the corresponding quantum system, which shows scars of the classical families in the semiclagsical regime. Two Hamiltonian systems with two degrees of freedom both displaying mixed (chaotic and regular) behaviour are analized. The first one is the elastic pendulum, its behaviour ususally presented as a paradigm of classical chaos. Essential aspects of its dinamics are studied to some extent and the classical (E, t ) plot is shown. The second system is the Spin- Boson Hamiltonian, a quantum system for which previous works have defined a classical analogue with chaotic behaviour and compiled the main families of periodic orbits. A quantum version of the (E, t ) plot for this model is shown, and the classical and quantum plots are compared in the regime of soft chaos. The fitting in the semiclassical limit is discussed with a qualitative agreement that indicates enhancements of the scars in the regions where bifurcations of period orbits occur / Mestrado / Física / Mestre em Física

Orientador: Grace Silva Deaecto / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-27T16:26:54Z (GMT). No. of bitstreams: 1 Suto_AlanPereira_M.pdf: 1433599 bytes, checksum: 847a72c2f990c5ca185477889617c8ff (MD5) Previous issue date: 2015 / Resumo: Esta dissertação trata do controle H2 de sistemas com comutação do tipo Lur¿e baseado no critério generalizado de Popov. Mais especificamente, uma nova regra de comutação dependente do estado e da entrada externa é proposta de tal forma a assegurar estabilidade assintótica global e um custo garantido H2 de desempenho. Esta nova estratégia de comutação é o ponto chave para a generalização do célebre critério de Popov. Como no caso de sistemas invariantes no tempo, propomos um teste de estabilidade baseado no domínio da frequência expresso em termos de uma certa combinação convexa das matrizes de espaço de estado dos subsistemas. Ademais, este teste leva em conta a inclusão de um índice de desempenho H2 cujo estudo, no presente contexto, é inédito na literatura. Os resultados teóricos obtidos são aplicados no controle de uma suspensão semi-ativa automotiva evidenciando a validade e a eficiência da função de comutação proposta / Abstract: This Master¿s dissertation deals with H2 control design of Lur¿e-type switched systems based on the generalized Popov criterion. More specifically, a novel state-input dependent switching rule is proposed in order to assure global asymptotic stability and an H2 guaranteed cost. This new switching strategy is the key issue to generalize the celebrated Popov criterion. Likewise the case of time invariant systems, we propose a frequency domain stability test that is expressed in terms of a certain convex combination of the subsystems state space matrices. Moreover, this test takes into account an H2 performance index whose study, in the present context, is new in the literature. The theoretical results are used to the control design of a car semiactive suspension and to put in evidence the validity and the efficiency of the proposed switching function / Mestrado / Mecanica dos Sólidos e Projeto Mecanico / Mestre em Engenharia Mecânica

Discussion of the application of mathematical softwares for the determination of frequency characteristics of mechanical systems

Single-carrier frequency division multiple access (SC-FDMA) has become a popular alternative to orthogonal frequency division multiple access (OFDM) in multi-user communication on LTE uplink systems. This is primarily due to the low peak-to-average power ratio (PAPR) of SC-FDMA compared to that of OFDM. Long-term evolution (LTE) uses SC-FDMA on the uplink to exploit this PAPR advantage to reduce transmit power amplifier (PA) back-off in mobile user terminals. However, the latest generation of communication systems requires high power efficiency and a large quantity of capacity in transmitting mobile data, bringing out some other critical problems: 1) the nonlinearity of Radio Frequency (RF) power amplifiers inevitably affects the power efficiency. Working beyond the saturation point is the main reason for power amplifiers having nonlinear properties; 2) In order to obtain adequate capacity, wide bandwidth is applied to the latest communication systems. Since in previous systems the pre-distorter would focus on memory-less distortion with relatively narrow bandwidth, this change makes memory distortion become a serious issue, degrading the transmission quality in the wireless communication systems. The intent of this thesis is to present nonlinear analysis of the SC-FDMA Spectrum with the RF power amplifier. Relevant mathematical models were considered and applied to the RF power amplifier in terms of intermodulation products and the third-order intercept point. The equivalent mathematical model is applied for the first time to SC-FDMA signals and with the previous formulation of the PA model, the derivation of the expressions for spectrum regrowth of amplified SC-FDMA signals was first established and finally simulated with Matlab software. The digital pre-distortion (DPD) technology was also applied to SC-FDMA signals for the first time in this thesis. An inverse intermodulation and Autoregressive Moving-Average (IM-ARMA) model was introduced to linearize the PA distortion with memory in the LTE uplink system. The DPD was finally implemented by Matlab R2010b. Conclusions are drawn that amplified power emission levels can be expressed by the form of third-order intercept point (IP_3). The expressions for spectrum regrowth of amplified SC-FDMA signals have been verified for the first time with the comparison of simulation, measurement and calculation results. The effects of third order intermodulation have a greater impact than higher order components with respect to out-of-band emission power levels. Furthermore, the DPD algorithm reduced the spectrum regrowth of SC-FDMA signals by 12 dB. The proposed pre-distorter can effectively solve the distortion problem caused by the memory effect in RF power amplifier.

Dans cette thèse, nous aborderons deux aspects fondamentaux qui se posent dans les systèmes de commande modernes du fait de l'interaction entre des processus en temps continu et des dispositifs numériques: la synthèse de lois de commande en présence de quantificateurs et l'estimation d'état en présence de mesures sporadiques. Une des caractéristiques principales de cette thèse consiste également à proposer des méthodes constructives pour résoudre les problèmes envisagés. Plus précisément, pour répondre à cette exigence, nous allons nous tourner vers une approche basée sur les inégalités matricielles linéaires (LMI). Dans la première partie de la thèse, nous proposons un ensemble d'outils constructifs basés sur une approche LMI, pour l'analyse et la conception de systèmes de commande quantifiés impliquant des modèles et des correcteurs linéaires. L'approche est basée sur l'utilisation des inclusions différentielles qui permet de modéliser finement le comportement de la boucle fermée et ainsi d'obtenir des résultats intéressants. Dans la seconde partie de la thèse, inspirés par certains schémas d'observation classiques présentés dans la littérature, nous proposons deux observateurs pour l'estimation de l'état d'un système linéaire en présence de mesures sporadiques, c'est-à-dire prenant en compte la nature discrète des mesures disponibles. De plus, en se basant sur une des deux solutions présentées, une architecture de commande basée observateur est proposée afin de stabiliser asymptotiquement un système linéaire en présence à la fois de mesures sporadiques et d'un accès intermittent à l'entrée de commande du système. / In this dissertation, two fundamental aspects arising in modern engineered control systems will be addressed:On the one hand, the presence of quantization in standard control loops. On the other hand, the state estimation in the presence of sporadic available measurements. These two aspects are addressed in two different parts. One of the main feature of this thesis consists of striving to derive computer-aided tools for the solution to the considered problems. Specifically, to meet this requirement, we revolve on a linear matrix inequalities (LMIs) approach. In the first part, we propose a set of LMI-based constructive Lyapunov-based tools for the analysis and the design of quantized control systems involving linear plants and linear controllers. The entire treatment revolves on the use of differential inclusions as modeling tools, and on stabilization of compact sets as a stability notion. In the second part of the thesis, inspired by some of the classical observation schemes presented in the literature of sampled-data observers, we propose two observers to exponentially estimate the state of a linear system in the presence of sporadic measurements. In addition, building upon one of the two observers, an observer-based controller architecture is proposed to asymptotically stabilize a linear plant in the presence of sporadic measurements and intermittent input access.