Controle de atitude de satélites artificiais utilizando um processador digital de sinais / Attitude control of satellites using a digital signal processor

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

14/09/2010

RESUMO

This work deals with the development and implementation of an attitude control system for an artificial satellite using a Digital Signal Processor (DSP). The dissertation presents a complete study of the attitude movement modeling and control for the continuous time systems case, considering the Linear Quadratic Regulator (LQR) and Linear Quadratic Gaussian (LQG) theories, and the use of gas jets actuators triggered through a pulsewidth pulse-frequency modulator (PWPF). The nonlinear dynamics of the satellite model is simulated in MATLAB/Simulink environment. The main features of the satellite considered in this study are from the Multi-Mission Platform (PMM), a satellite developed by the National Institute for Space Researches (INPE, Brazil), and the controller operation context is the attitude stabilization around the nominal parameters values. The work also covers a brief review of the fundamentals concepts involving signals and digital systems, the requirements an application of embedded systems to real time control, and a presentation of the DSP adopted in this work, the Blackfin BF537 contained in the ADSP−BF537 EZ−KIT Lite from Analog Devices. The tool adopted to the system implementation is the Real-Time Workshop from the package MATLAB/Simulink, that makes possible the conversion of Simulink models directly in C or C++ codes, which can be implemented in a embedded system for real time application. The co-simulation scheme, as well the conection between the nonlinear satellite model running in Simulink and the digital controller running in the DSP, is enabled by the Processor In the Loop co-simulation from the Real−Time Workshop Embedded Coder. The crucial questions concerning the operation of the numeric simulations scheme and tests, are the analog controller conversion to an application in discretized time, and the synchronization of the data communication between the DSP and the computer, that simulates the satellite dynamics. The obtained results in the validation tests of through the co-simulation, presented the correct conection between the MATLAB and the DSP, besides the satisfactory performance of the controlled dynamics response of the satellite attitude, which showed itself similar to that one obtained in the numerical simulations with the analog controller, fully performed in the MATLAB/Simulink environment.

ASSUNTO(S)

attitude control systems - mathematical models sistemas de controle de atitude - modelos matematicos processador digital de sinais satélites artificiais engenharia aeroespacial artificial satellites, digital signal processor

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