Orientation control using oscillating momentum wheels

This paper addresses the problem of controlling a rigid body's orientation by actuating sinusoidal oscillations of internal momentum wheels. We consider the rotational dynamics of a rigid body having three momentum wheels (one for each bodyfixed axis) that are attached to the body by springs. Each wheel is actuated by an internal sinusoidal torque of fixed frequency. The frequency of all sinusoidal torques is equal, but the amplitudes and phases can be varied independently. We analyze the inverse-dynamics problem of determining the amplitudes and phases for each sinusoidal torque such that a desired orientation is achieved. We then present two closed-loop orientation controllers based on this analysis. Numerical simulations demonstrate the effectiveness of the control techniques.