Orientador: Alberto Luiz Serpa / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-04T03:07:46Z (GMT). No. of bitstreams: 1 Lopes_JeanCutrim_M.pdf: 5625354 bytes, checksum: a90581a7277feed28b2e913c2e7ed085 (MD5) Previous issue date: 2005 / Resumo: o objetivo deste trabalho é aplicar o controle H2/H 'Infinito'usando desigualdades matriciais lineares com restrições de alocação de pólos em estruturas flexíveis. O problema de controle H2/H'Infinito' é uma técnica usada para a obtenção de controladores com as propriedades do controle norma H2, que trás desempenho ótimo, e do controle norma H 'Infinito' que proporciona desempenho dinâmico robusto. As desigualdades matriciais lineares permitem que a obtenção do controlador seja formulada como um problema de otimização convexa e com restrições adicionais tais como as referentes à alocação de pólos. O problema de alocação de pólos é importante para ajustar o comportamento dinâmico da planta controlada no que se refere a especificações em termos da velocidade de resposta e do amortecimento, por exemplo. O modelo empregado para o estudo foi uma viga sujeita a distúrbios com o controlador atuando de forma não colocada. As matrizes de estado empregadas ao estudo de controle foram determinadas através das matrizes obtidas pelo método dos elementos finitos, considerando o modelo de viga de Euler-Bemoulli. Os resultados mostraram que o uso da alocação dos pólos melhora o desempenho do controlador H2/H'Infinito'. Para a implementação computacional foi utilizado o aplicativo Matlab / Abstract: The objective ofthis work is to apply the H2/H'Infinity' control technique using linear matrix inequalities and pole placement constraints to the flexible structures control problem. The H2/H'Infinity' control is a technique to design a controller with mixed features of the H2 and H'Infinity' control formulations, such as, optimal dynamical performance and robust performance. The Linear Matrix Inequalities allow to formulate the problem as a convex optimization problem, and additional constraints can be included such as the pole placement. The pole placement requirement comes ftom the necessity of adjusting the transient response of the plant and ensuring specific behavior in terms of speed and damping responses. The mathematical model used for this study is related to a flexible beam, with an applied disturbance and an actuator in different positions. The state-space matrices of the structure were obtained using the finite element method with the Euler-Bernoulli formulation of beams. The results show that the pole placement constraints can improve the performance of the controller H2/H'Infinity',The Matlab was used for the computational implementation / Mestrado / Projeto Mecanico e Mecanica dos Solidos / Mestre em Engenharia Mecânica

Orientador: Grace Silva Deaecto / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-27T00:51:44Z (GMT). No. of bitstreams: 1 Santos_GuilhermeCavalari_M.pdf: 16424850 bytes, checksum: 7f2f16f9c4c4f920f928c8d19273978a (MD5) Previous issue date: 2015 / Resumo: Esta dissertação trata do projeto de controle H2 e Hoo via realimentação de estado para sistemas afins com comutação a tempo contínuo. Nosso objetivo principal é projetar um conjunto de ganhos de realimentação de estado e uma função de comutação assegurando estabilidade assintótica global do ponto de equilíbrio desejado. Este ponto deve pertencer a um conjunto de pontos de equilíbrio atingíveis a ser determinado. Além disso, o projeto deve levar em conta índices de desempenho H2 e Hoo que são adequadamente definidos. Para o projeto de controle Hoo, duas funções de comutação são propostas e discutidas. A primeira delas depende somente do estado, enquanto a segunda representa uma nova proposta que é mais geral e depende também da entrada externa. As condições obtidas são menos conservadoras do que as técnicas recentes disponíveis na literatura, por exemplo, os métodos baseados na função de Lyapunov do tipo máximo e os utilizados normalmente para assegurar estabilidade prática. Exemplos numéricos ilustram os resultados teóricos obtidos e são usados para comparações / Abstract: This Master's thesis deals with state feedback H2 and Hoo control design of continuous-time switched affine systems. Our main goal is to design a set of state feedback gains and a switching function assuring global asymptotical stability of a desired equilibrium point. This point must belong to a set of attainable equilibrium points to be determined. Moreover, the design must consider H2 and Hoo performance indexes to be defined. For the Hoo control design, two different switching functions are proposed and discussed. The first one depends only on the state and the other depends on the state and on the external input. The conditions are less conservative than the techniques available in the literature to date, as for instance, those based on a max-type Lyapunov function and those commonly used to assure practical stability. Numerical examples illustrate the theoretical results and are used for comparisons / Mestrado / Mecanica dos Sólidos e Projeto Mecanico / Mestre em Engenharia Mecânica

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

A remote-sensing acoustic method for implementing position control feedback in Scanning Probe Microscopy (SPM) is presented. The capabilities of this feedback control using the new Whispering Gallery Acoustic Sensing (WGAS) method is demonstrated in a Shear-force Scanning Probe Microscope that uses a sharp probe attached to a piezoelectric Quartz Tuning Fork (QTF) firmly mounted on the microscope's frame. As the QTF is electrically driven its mechanical response reaches the SPM frame which then acts as a resonant cavity producing acoustic modes measured with an acoustic sensor strategically placed on the SPM head. The novelty of the WGAS resides in using an SPM frame with a perimeter closely matching the intervening acoustic wavelength to act as a resonant cavity. The whispering gallery cavity constitutes an acoustic amplifier for the mechanical motion of the QTF probe. The observed monotonic behavior of the whispering gallery acoustic signal as a function of the probe sample distance is exploited here for tip-sample distance control with nanometer sensitivity, thus allowing topographic characterization as the probe is scanned across the sample's surface. This thesis includes a description of a Labview based programming for the Field Programmable Gate Array (FPGA) card used in the automated control of the WGAS feedback microscope, a solution for improving the effective resolution of the Digital to Analog Converter (DAC) and initial results towards theoretically modeling the WGAS working principle.

This dissertation presents a discussion of the optimal feedback control for nonliner systems (both discrete and ODE) and nonquadratic cost functions in order to achieve improved performance and larger regions of asymptotic stability in the nonlinear system context. The main work of this thesis is carried out in two parts; the first involves development of nonlinear, nonquadratic theory for nonlinear recursion equations and formulation, proof and application of the stable manifold theorem as it is required in this context in order to obtain the form of the optimal control law. The second principal part of the dissertation is the development of nonlinear, nonquadratic theory as it relates to nonautonomous systems of a particular type; specifically periodic time varying systems with a fixed, time invariant critical point. / Ph. D.

This thesis considers the application of singular value decomposition (SVD) and semi-nonnegative matrix factorization (SNMF) within feedback control systems, called the SVD System and SNMF System, to control numerous subsystems with a reduced number of control inputs. The subsystems are coupled using a row-column structure to allow mn subsystems to be controlled using m+n inputs. Past techniques for controlling systems in this row-column structure have focused on scheduling procedures that offer limited performance. The SVD and SNMF Systems permit simultaneous control of every subsystem, which increases the convergence rate by an order of magnitude compared with previous methods. In addition to closed loop control, open loop procedures using the SVD and SNMF are compared with previous scheduling procedures, demonstrating significant performance improvements. This thesis presents theoretical results for the controllability of systems using the row-column structure and for the stability and performance of the SVD and SNMF Systems. Practical challenges to the implementation of the SVD and SNMF Systems are also examined. Numerous simulation examples are provided, in particular, a dynamic simulation of a pin array device, called Digital Clay, and two physical demonstrations are used to assess the feasibility of the SVD and SNMF Systems for specific applications.

Helicopters are often used to transport supplies and equipment. When a heavy load is carried via suspension cables below a helicopter, the load oscillates in response to helicopter motion and disturbance forces, such as wind. This oscillation is dangerous and adversely affects control of the helicopter, especially when carrying large or heavy loads. By adding input shaping to the helicopter's flight controller, the suspended load oscillation caused by helicopter motion is greatly reduced. A significant benefit of this approach is that it does not require measurement of the load position. This thesis contains derivations and analysis of simple planar helicopter-load dynamic models, and these models are verified using experimental data from model-scale, radio-controlled helicopters. The effectiveness of input shaping at eliminating suspended load oscillation is then demonstrated on this experimental hardware. In addition, the design of an attitude command, near-hover flight controller that combines input shaping and a common flight control architecture is illustrated using dynamic models of a Sikorsky S-61 helicopter, and simulation results are shown for example lateral and longitudinal repositioning movements. Results show that applying input shaping to simulated pilot commands greatly improves performance when carrying a suspended load.

Radio Frequency Low Noise and High Q Integrated Filters in Digital CMOS Processes Zhijie Xiong 149 pages Directed by Dr. Phillip E. Allen Presented in this work is a novel design technique for CMOS integration of RF high Q integrated filters using positive feedback and current mode approach. Two circuits are designed in this work: a 100MHz low-noise and high Q bandpass filter suited for an FM radio front-end, and a 2.4GHz low-noise and high-Q bandpass filter suited for a Bluetooth front-end. Current-mode approach and positive feedback design techniques are successfully used in the design of both circuits. Both circuits are fabricated through a 0.18um CMOS process provided by National Semiconductor Corp. The 100MHz circuit achieves 3.15uV RF sensitivity with 26dB SNR, and the total current consumption is 12mA. The center frequency of the filter is tunable from 80MHz to 110MHz, and the Q value is tunable from 0.5 to 28.9. 1 dB compression point is measured as -34.0dBm, combined with noise measurement results, a dynamic range of 54.1 dB results. Silicon area of the core circuit is 0.4 square millimeters. The center frequency of the 2.4GHz circuit is tunable from 2.4GHz to 2.5GHz, and the Q value is tunable from 20 to 120. The 1 dB compression dynamic range of the circuit is 50dB. Integrated spiral inductors are developed for this design. Patterned ground shields are laid out to reduce inductor loss through substrate, especially eddy current loss when the circuit is fabricated on epi wafers. Accumulation mode MOS varactors are designed to tune the frequency response. Silicon area of the core circuit is 1 square millimeter.

The ultimate goal of this research is to develop a method, from the designers point of view, for using the embodied specialized knowledge of Finite Element Analysis [FEA] software to study the behavior of materials, geometries, and configurations in order to create an iterative design feedback loop that uses structural performance as a primary evaluation criteria and point of departure for generating and refining complex formo-techtonic configurations while ensuring constructability, improved structural performance, and syntactic consistency. Syntactic consistency meaning that there would not be a loss in translation from concept to construct. Instead of the 2-dimensional [planar] manual technology which drove modernist analysis towards the structural hyper-rationality of the trabeated system, this new process should compile and synthesize computational speed, mathematic principles, mechanical knowledge, and material logics within a digital 3-dimensional [spatial] analytical environment in order to realize a new paradigm of constructible spatialized sensuality. The research will focus on the development of interoperability techniques and protocols between advanced parametric CAD systems and advanced structural analysis systems towards the creation of a fluid design + analysis process of creating and engineering complex forms and dynamic systems. Rapid prototyping will be integrated as a secondary feedback and verification loop, and as a precursor to the production of full scale construction machine readable files. In other words, the research focuses on the development of intricately designed, geometrically complex, and materially sophisticated structural skins that can be produced through advanced CAD/CAM techniques.

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