A reduced-effort control law for underactuated rigid bodies

Previous results show that a nonsmooth, time-invariant feedback control law can be used to stabilize an axisymmetric rigid body using only two control torques to the zero equilibrium. This method, however, may require a significant amount of control effort, especially for initial conditions close to an equilibrium manifold. In this paper we propose a modification of the previous control law which reduces the control effort required. A rigid spacecraft is considered