SPACECRAFT ATTITUDE CONTROL SYSTEM DESIGN CONSIDERING FUEL SLOSH DYNAMICS AND PARAMETERS ESTIMATION

Resumo

The design of the satellite Attitude Control System (ACS) becomes more complex when the
satellite structure has great number of components like, flexible solar panels and antennas, mechanical
manipulators and tanks with fuel. Besides, the ACS performance and robustness depend on the effects
of dynamics interaction between these components being considered in the satellite controller design.
When the satellite is performing a translational and/or rotational maneuver the fuel slosh motion can
change the center of mass position damaging the ACS accuracy. Therefore, controller performance and
robustness depend not only on a good control technique but also on the knowledge of the system
interactions characteristics. In this paper one apply the Linear Quadratic Regulator (LQR) technique to
designs the ACS for a rigid satellite with a partially filled fuel tank taking into account the slosh
dynamics using mechanical analogies type pendulum. During the LQR controller design some physical
parameters of the system are estimated using the Kalman filter technique. The focus of the estimation is
the length of the pendulum which represents the sloshing dynamics. The investigation is performed
considering planar maneuver of the satellite caused by fixed thruster.