Balancing of NARO Reaction Wheel SRF-361

Balancing of NARO Reaction Wheel SRF-361

Momentum type wheels-Reaction Wheels or Control Moment Gyros- have been used as primary actuators for satellite attitude control. Rotation of wheel, however, induces torque and force disturbances, which degrade the attitude control qualities. The disturbances are generated from the static and dynamic imbalances of the wheel which are mainly due to the irregular mass distribution and the axis misalignment. These imbalances shall be minimized by balancing on the stage of wheel manufacturing and assembly. Disturbances of the first flight model reaction wheel developed in Korea for NARO STSAT-2C are measured on the torque/force measurement table. The magnitude and phase of the imbalances are identified with the Power Spectrum Density plot and z-phase detection method. The imbalances have been remarkably reduced after following two counter-weighing steps:static and dynamic balancing.