This paper deals with nonlinear feedback stabilization problem of a flexible beam clamped at a rigid body and free at the stabilization problem of a flexible beam clamped at a rigid body and free at the other end. We assume that there is no damping. The feedback law proposed hereother end. We assume that there is no damping. The feedback law proposed here consists of a nonlinear control torque applied to the rigid body and either a consists of a nonlinear control torque applied to the rigid body and either a nonlinear boundary control moment or a nonlinear boundary control force or both nonlinear boundary control moment or a nonlinear boundary control force or both of them applied to the free end of the beam. This nonlinear feedback, which insures the exponential decay of the beam vibrations, extends the which insures the exponential decay of the beam vibrations, extends the linear case studied by Laousy et al. to a more general class of controls. This new class of controls is in particular of the interest to be robust.