Miniature BLDC Motor in Nano Reaction Wheel for Small Satellites and Space Robots/Free-Flyers

Nanosatellites become popular due to the fast-growing satellite industry and the demand for clustered space elements. The scope and applications of nanosatellites have increased with the advancements in Space Robots. The optimum sizing and minimal footprints are its major highlights. A three-phase, 12-pole BLDC motor is being used for the high-speed rotation of the flywheel. The drive motor configuration is thoroughly studied, and an enclosed type double rotor configuration has been selected to reduce the magnetic losses and, hence, the steady state power demand of the wheel. FE simulation analysis is carried out in detail to optimize the magnetic circuit of the motor so that the torque to rotor volume and power density of the motor is increased. The realized motor is tested for the Back EMF and developed torque, and the required torque constant is established. Design improvements and modifications to the existing BLDC motor are projected to cater to the requirements of Space Robot. Hermetic sealing of the wheel is required to avoid the loss of lubrication due to moisture contamination. Instead of the traditional way, the adhesive bonding-based process is implemented for the hermetic sealing of casing assembly. The major challenges in achieving an optimized BLDC to satisfy the mission/project requirements are also addressed.