Attitude maneuver control of a two-wheeled spacecraft with bounded wheel speeds

The attitude control problem of a spacecraft using two reaction wheels is revisited. Controllability analysis shows that the reduced dynamics of a two-wheeled spacecraft are locally controllable at any equilibrium if the total angular momentum of the system is zero, and all the possible equilibrium attitudes form the whole attitude configuration manifold. Under zero-momentum restriction, a singular quaternion feedback controller is first derived based on the generalized dynamic inverse method to stabilize the attitude kinematics. By introducing a novel saturated function, this controller is developed into a switching control logic to account for the singularities as well as yielding bounded inputs. Then a full-state feedback with bounded wheel speeds is synthesized to globally reorientate the spacecraft to any desired orientation. Numerical simulation results demonstrate the effectiveness of the proposed control algorithm.