Detecção e acomodação de falhas em sistemas incertos com atraso no sinal de controle utilizando modo deslizante

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Controle com modos deslizantes aplicado em sistemas com atraso e acesso somente à saída

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Dinâmica não-linear de um sistema mono-pendular invertido, excitado por um vibrador eletrodinâmico de potência controlada

Pós-graduação em Engenharia Mecânica - FEB

Modelagem matemática e análise dinâmica da torre de um pulverizador de pomares

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Projetos de controle discreto com modos deslizantes para sistemas sujeitos a atraso no controle

Pós-graduação em Engenharia Elétrica - FEIS

Controle discreto com modos deslizantes em sistemas incertos com atraso no sinal de controle

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Modelagem e controle de sistemas fuzzy Takagi-Sugeno

Pós-graduação em Engenharia Elétrica - FEIS

Análise da robustez e aplicações de controle com modos deslizantes em sistemas incertos com atraso no controle

Pós-graduação em Engenharia Elétrica - FEIS

Dynamic stabilization of Rayleigh-Taylor instability of ablation fronts in inertial confinement fusion

One of the most important problems in inertial confinement fusion is how to find a way to mitigate the onset of the Rayleigh-Taylor instability which arises in the ablation front during the compression. In this thesis it is studied in detail the possibility of using for such a purpose the well-known mechanism of dynamic stabilization, already applied to other dynamical systems such as the inverted pendulum. In this context, a periodic acceleration superposed to the background gravity generates a vertical vibration of the ablation front itself. The effects of different driving modulations (Dirac deltas and square waves) are analyzed from a theoretical point of view, with a focus on stabilization of ion beam driven ablation fronts, and a comparison is made, in order to look for optimization.

New methods for the estimation of Takagi-Sugeno model based extended Kalman filter and its applications to optimal control for nonlinear systems

This paper describes new approaches to improve the local and global approximation (matching) and modeling capability of Takagi–Sugeno (T-S) fuzzy model. The main aim is obtaining high function approximation accuracy and fast convergence. The main problem encountered is that T-S identification method cannot be applied when the membership functions are overlapped by pairs. This restricts the application of the T-S method because this type of membership function has been widely used during the last 2 decades in the stability, controller design of fuzzy systems and is popular in industrial control applications. The approach developed here can be considered as a generalized version of T-S identification method with optimized performance in approximating nonlinear functions. We propose a noniterative method through weighting of parameters approach and an iterative algorithm by applying the extended Kalman filter, based on the same idea of parameters’ weighting. We show that the Kalman filter is an effective tool in the identification of T-S fuzzy model. A fuzzy controller based linear quadratic regulator is proposed in order to show the effectiveness of the estimation method developed here in control applications. An illustrative example of an inverted pendulum is chosen to evaluate the robustness and remarkable performance of the proposed method locally and globally in comparison with the original T-S model. Simulation results indicate the potential, simplicity, and generality of the algorithm. An illustrative example is chosen to evaluate the robustness. In this paper, we prove that these algorithms converge very fast, thereby making them very practical to use.

A new approach to fuzzy estimation of Takagi-Sugeno model and its applications to optimal control for nonlinear systems

An efficient approach is presented to improve the local and global approximation and modelling capability of Takagi-Sugeno (T-S) fuzzy model. The main aim is obtaining high function approximation accuracy. The main problem is that T-S identification method cannot be applied when the membership functions are overlapped by pairs. This restricts the use of the T-S method because this type of membership function has been widely used during the last two decades in the stability, controller design and are popular in industrial control applications. The approach developed here can be considered as a generalized version of T-S method with optimized performance in approximating nonlinear functions. A simple approach with few computational effort, based on the well known parameters' weighting method is suggested for tuning T-S parameters to improve the choice of the performance index and minimize it. A global fuzzy controller (FC) based Linear Quadratic Regulator (LQR) is proposed in order to show the effectiveness of the estimation method developed here in control applications. Illustrative examples of an inverted pendulum and Van der Pol system are chosen to evaluate the robustness and remarkable performance of the proposed method and the high accuracy obtained in approximating nonlinear and unstable systems locally and globally in comparison with the original T-S model. Simulation results indicate the potential, simplicity and generality of the algorithm.

Variable structure control with chattering reduction of a generalized T-S model

In this paper, a fuzzy logic controller (FLC) based variable structure control (VSC) is presented. The main objective is to obtain an improved performance of highly non-linear unstable systems. New functions for chattering reduction and error convergence without sacrificing invariant properties are proposed. The main feature of the proposed method is that the switching function is added as an additional fuzzy variable and will be introduced in the premise part of the fuzzy rules; together with the state variables. In this work, a tuning of the well known weighting parameters approach is proposed to optimize local and global approximation and modelling capability of the Takagi-Sugeno (T-S) fuzzy model to improve the choice of the performance index and minimize it. The main problem encountered is that the T-S identification method can not be applied when the membership functions are overlapped by pairs. This in turn restricts the application of the T-S method because this type of membership function has been widely used in control applications. The approach developed here can be considered as a generalized version of the T-S method. An inverted pendulum mounted on a cart is chosen to evaluate the robustness, effectiveness, accuracy and remarkable performance of the proposed estimation approach in comparison with the original T-S model. Simulation results indicate the potential, simplicity and generality of the estimation method and the robustness of the chattering reduction algorithm. In this paper, we prove that the proposed estimation algorithm converge the very fast, thereby making it very practical to use. The application of the proposed FLC-VSC shows that both alleviation of chattering and robust performance are achieved.

Diseño, construcción y control de un robot balancín.

Se diseñó, construyó, simuló e implementó un dispositivo robot balancín para la aplicación y estudio de técnicas avanzadas de control. Para esto se realizó el diseño mecánico del dispositivo, de acuerdo a una elección entre dos modelos distintos y cuatro tipos diferentes de transmisión. Luego se instrumentó el dispositivo con encoders de posición , acelerómetro y giróscopo para obtener el estado del dispositivo y controlarlo. Se realizó una placa electrónica para la lectura y procesamiento de señales de sensores con un micro controlador, un regulador de tensión, y un driver para los motores, capaz de obtener las señales de los encoders y el módulo acelerómetro-giróscopo y enviarlas por comunicación hacia una mini-computadora, la cual ejecuta el control, y se comunica nuevamente a la placa diseñada para comandar los motores. Se desarrolló un modelo teórico simplificado en dos dimensiones para facilitar la posterior identificación de planta. Se realizaron experimentos para lograr una identificación de planta. A partir de lo obtenido, se diseñó y simuló el control necesario para mantener la estabilidad. Se implementó posteriormente el control diseñado. Se reajustaron los parámetros correspondientes de acuerdo a la práctica experimental para mejorar la respuesta dinámica del sistema.

Diseño, construcción y control de un robot balancín.

Se diseñó, construyó, simuló e implementó un dispositivo robot balancín para la aplicación y estudio de técnicas avanzadas de control. Para esto se realizó el diseño mecánico del dispositivo, de acuerdo a una elección entre dos modelos distintos y cuatro tipos diferentes de transmisión. Luego se instrumentó el dispositivo con encoders de posición , acelerómetro y giróscopo para obtener el estado del dispositivo y controlarlo. Se realizó una placa electrónica para la lectura y procesamiento de señales de sensores con un micro controlador, un regulador de tensión, y un driver para los motores, capaz de obtener las señales de los encoders y el módulo acelerómetro-giróscopo y enviarlas por comunicación hacia una mini-computadora, la cual ejecuta el control, y se comunica nuevamente a la placa diseñada para comandar los motores. Se desarrolló un modelo teórico simplificado en dos dimensiones para facilitar la posterior identificación de planta. Se realizaron experimentos para lograr una identificación de planta. A partir de lo obtenido, se diseñó y simuló el control necesario para mantener la estabilidad. Se implementó posteriormente el control diseñado. Se reajustaron los parámetros correspondientes de acuerdo a la práctica experimental para mejorar la respuesta dinámica del sistema.