Attitude Control of a Micro Satellite Using Magnetic Bearing Momentum Wheel.

An attitude controller for a 50 kg-class micro satellite which could be launched by H-II rocket as a piggyback payload of a main satellite is considered. One of the candidate configurations for such an attitude controller is bias momentum control using a magnetically suspended momentum wheel with gimballing capability. Magnetic bearings can generate internal torques and tilt the axis of the momentum wheel relative to the despun mainbody, and this function can be used for the active stabilization of the attitude motion of the satellite. The disturbance torque acting on the satellite caused by the release of a tethered subsatellite from it is estimated for the controller design. The attitude controller for estimated disturbance is designed based on the linearized equations of motion of it applying the H∞ control theory. The performance of the controller is evaluated through numerical simulation.