Project - Magnetically Suspended Reaction Sphere

Magnetically Suspended Reaction Sphere


Lei Zhou


MIT Lincoln Laboratory

Goal of the Project: Small satellite angular attitude control with a suspended sphere of uniform hard steel instead of 3 reaction wheels; Novel hysteresis drive can generate torque, and stabilize translation in three axes without mechanical bearing.

Introduction: Typical attitude control for small satellites are using 3 reaction wheels in 3 axis, which has the limit of pointing stability due to wheel imbalance, friction disturbances and bearing vibration. In this project we are considering to replace 3 reaction wheels with 1 reaction sphere. In the control scheme, the sphere is magnetically suspended therefore there will be no friction drag; and the sphere is driven with hysteresis motor for moment storage. Currently we are taking the initial steps to demonstrate 1-D prototype, which is a solid spherical rotor being levitated in 3 DOFs and rotating about 1 axis.  To see figures, click here.