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Mathematical Problems in Engineering
Volume 2009, Article ID 750945, 17 pages
Research Article

Optimal On-Off Attitude Control for the Brazilian Multimission Platform Satellite

1Center for Applied Space Technology and Microgravity, (ZARM) Am Fallturm, University of Bremen, 28359 Bremen, Germany
2Center of Engineering, Modelling and Applied Social Sciences, Federal University of ABC, Rua Catequese 242, 09090-400 Santo André, SP, Brazil
3Graduate Program on Information Engineering, Federal University of ABC, Rua Catequese 242, 09090-400 Santo André, SP, Brazil

Received 24 June 2009; Accepted 13 August 2009

Academic Editor: Maria Zanardi

Copyright © 2009 Gilberto Arantes Jr. et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


This work deals with the analysis and design of a reaction thruster attitude control for the Brazilian Multimission platform satellite. The three-axis attitude control systems are activated in pulse mode. Consequently, a modulation of the torque command is compelling in order to avoid high nonlinear control action. This work considers the Pulse-Width Pulse-Frequency (PWPF) modulator which is composed of a Schmidt trigger, a first-order filter, and a feedback loop. PWPF modulator holds several advantages over classical bang-bang controllers such as close to linear operation, high accuracy, and reduced propellant consumption. The Linear Gaussian Quadratic (LQG) technique is used to synthesize the control law during stabilization mode and the modulator is used to modulate the continuous control signal to discrete one. Numerical simulations are used to analyze the performance of the attitude control. The LQG/PWPF approach achieves good stabilization-mode requirements as disturbances rejection and regulation performance.