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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Modelagem e controle de uma classe de sistemas multi-corpos móveis. / Modeling and control of a class of mobile multi-body systems.

Souza, Eric Conrado de 22 April 2008 (has links)
No que segue, propõe-se uma classe de sistemas robóticos multi-corpos, cujos corpos componentes estão fisicamente acoplados através de juntas rotativas ativas. Os sistemas da classe considerada possuem mobilidade irrestrita no espaço plano uma vez que propulsores distribuídos ao longo dos corpos do sistema. A modelagem dinâmica destes sistemas é apresentada sob as abordagens Hamiltoniana e Lagrangiana da mecânica analítica. A descrição destes métodos de modelagem, assim como os modelos por eles obtidos, é realizada com ênfase na interpretação geométrica da matemática envolvida. Alguns exemplos de parametrizações do espaço de fase do sistema são discutidos e exemplos de modelagem em função destas parametrizações são obtidos. Ademais, alguns critérios de análise de controlabilidade não-linear são revisados e aplicados aos modelos do sistema com a estrutura de entradas considerada. Alguns casos de estabilização da classe de sistemas são também discutidos. Resultados de simulação de estabilização são obtidos para sistemas através de estudos de casos. Sistemas completamente controlados no espaço de estados podem ser linearizados através de uma técnica de linearização por realimentação e estabilizados com uma realimentação de estados. Para os sistemas cuja controlabilidade é deficiente, propõe-se a modificação de um método de controle de sistemas sub-atuados e uma lei de controle por realimentação é obtida pela teoria de estabilidade de Lyapunov. A classe de sistemas aqui discutida possui grande potencial de aplicação nos ambientes espacial e submarino. / In the following, a class of multi-body robotic systems is proposed in which its system component bodies are physically coupled by active rotating joints. The systems belonging to the proposed class have unrestricted mobility on the plane since thrusters are distributed along the system. System dynamical modeling is obtained through the analytic mechanical Hamiltonian and Lagrangian methods. The presentation of these methods, as well as the dynamical models obtained by them, is realized with an emphasis in the geometrical interpretation of the corresponding mathematics. A few different system phase space parameterizations approaches are discussed and modeling examples are presented under these parameterizations. Additionally, some nonlinear controllability analysis criteria are reviewed and applied to system dynamical models composed by the input structure mentioned above. A few stabilization case studies for the class of systems are also discussed and simulation results are presented. Totally controlled systems in the phase space can be linearized by feedback linearization techniques and stabilized through a state feedback. For partially controllable systems a modification of a stabilization method for under-actuated systems is proposed which renders feedback control via Lypunov stability theory. The class of systems discussed has great potential for space and underwater applications.
2

Modelagem e controle de uma classe de sistemas multi-corpos móveis. / Modeling and control of a class of mobile multi-body systems.

Eric Conrado de Souza 22 April 2008 (has links)
No que segue, propõe-se uma classe de sistemas robóticos multi-corpos, cujos corpos componentes estão fisicamente acoplados através de juntas rotativas ativas. Os sistemas da classe considerada possuem mobilidade irrestrita no espaço plano uma vez que propulsores distribuídos ao longo dos corpos do sistema. A modelagem dinâmica destes sistemas é apresentada sob as abordagens Hamiltoniana e Lagrangiana da mecânica analítica. A descrição destes métodos de modelagem, assim como os modelos por eles obtidos, é realizada com ênfase na interpretação geométrica da matemática envolvida. Alguns exemplos de parametrizações do espaço de fase do sistema são discutidos e exemplos de modelagem em função destas parametrizações são obtidos. Ademais, alguns critérios de análise de controlabilidade não-linear são revisados e aplicados aos modelos do sistema com a estrutura de entradas considerada. Alguns casos de estabilização da classe de sistemas são também discutidos. Resultados de simulação de estabilização são obtidos para sistemas através de estudos de casos. Sistemas completamente controlados no espaço de estados podem ser linearizados através de uma técnica de linearização por realimentação e estabilizados com uma realimentação de estados. Para os sistemas cuja controlabilidade é deficiente, propõe-se a modificação de um método de controle de sistemas sub-atuados e uma lei de controle por realimentação é obtida pela teoria de estabilidade de Lyapunov. A classe de sistemas aqui discutida possui grande potencial de aplicação nos ambientes espacial e submarino. / In the following, a class of multi-body robotic systems is proposed in which its system component bodies are physically coupled by active rotating joints. The systems belonging to the proposed class have unrestricted mobility on the plane since thrusters are distributed along the system. System dynamical modeling is obtained through the analytic mechanical Hamiltonian and Lagrangian methods. The presentation of these methods, as well as the dynamical models obtained by them, is realized with an emphasis in the geometrical interpretation of the corresponding mathematics. A few different system phase space parameterizations approaches are discussed and modeling examples are presented under these parameterizations. Additionally, some nonlinear controllability analysis criteria are reviewed and applied to system dynamical models composed by the input structure mentioned above. A few stabilization case studies for the class of systems are also discussed and simulation results are presented. Totally controlled systems in the phase space can be linearized by feedback linearization techniques and stabilized through a state feedback. For partially controllable systems a modification of a stabilization method for under-actuated systems is proposed which renders feedback control via Lypunov stability theory. The class of systems discussed has great potential for space and underwater applications.
3

Understanding Cognition via Complexity Science

Favela, Luis H., Jr. 02 June 2015 (has links)
No description available.
4

A Novel Control Engineering Approach to Designing and Optimizing Adaptive Sequential Behavioral Interventions

January 2014 (has links)
abstract: Control engineering offers a systematic and efficient approach to optimizing the effectiveness of individually tailored treatment and prevention policies, also known as adaptive or ``just-in-time'' behavioral interventions. These types of interventions represent promising strategies for addressing many significant public health concerns. This dissertation explores the development of decision algorithms for adaptive sequential behavioral interventions using dynamical systems modeling, control engineering principles and formal optimization methods. A novel gestational weight gain (GWG) intervention involving multiple intervention components and featuring a pre-defined, clinically relevant set of sequence rules serves as an excellent example of a sequential behavioral intervention; it is examined in detail in this research.   A comprehensive dynamical systems model for the GWG behavioral interventions is developed, which demonstrates how to integrate a mechanistic energy balance model with dynamical formulations of behavioral models, such as the Theory of Planned Behavior and self-regulation. Self-regulation is further improved with different advanced controller formulations. These model-based controller approaches enable the user to have significant flexibility in describing a participant's self-regulatory behavior through the tuning of controller adjustable parameters. The dynamic simulation model demonstrates proof of concept for how self-regulation and adaptive interventions influence GWG, how intra-individual and inter-individual variability play a critical role in determining intervention outcomes, and the evaluation of decision rules.   Furthermore, a novel intervention decision paradigm using Hybrid Model Predictive Control framework is developed to generate sequential decision policies in the closed-loop. Clinical considerations are systematically taken into account through a user-specified dosage sequence table corresponding to the sequence rules, constraints enforcing the adjustment of one input at a time, and a switching time strategy accounting for the difference in frequency between intervention decision points and sampling intervals. Simulation studies illustrate the potential usefulness of the intervention framework. The final part of the dissertation presents a model scheduling strategy relying on gain-scheduling to address nonlinearities in the model, and a cascade filter design for dual-rate control system is introduced to address scenarios with variable sampling rates. These extensions are important for addressing real-life scenarios in the GWG intervention. / Dissertation/Thesis / Doctoral Dissertation Chemical Engineering 2014

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