Design of a Low Micro Vibration High Precision CubeSat Reaction Wheel

Missions involving payloads such as laser communications or astronomical objectives often have high pointing requirements. Arcsec is developing a CubeSat reaction wheel, dubbed "Zyra", in cooperation with the KU Leuven University and ESA under the GSTP program, to serve such demanding missions. The reaction wheel is a 160g wheel of 40x40x23mm³ with a momentum capacity of 27.5mNm. The wheel has its own integrated power electronics which are tuned to the motor's low inductance and allowing full four quadrant control. It houses its own microprocessor and integrated control algorithms, allowing the reaction wheel assembly to function as a standalone unit with just a torque demand input from the ADCS controller. The ultimate goal of the project is to make a high-precision, low micro-vibration reaction wheel. To achieve this goal, the design of the wheels are balanced to ISO grade G0.4 and a preloaded suspension system is used while keeping the housing rigid and stiff to avoid resonances at low frequencies. To further improve the micro-vibration performance, the rotor structure is damped using constrained layer damping. Such a system allows to damp the rotor resonance frequencies while keeping the advantages of a single piece rotor and leaving the stiffness, mass and dimensions virtually unaffected.