  This paper provides new results for a tracking control of the attitude
dynamics of a rigid body. Both of the attitude dynamics and the proposed
control system are globally expressed on the special orthogonal group, to avoid
complexities and ambiguities associated with other attitude representations
such as Euler angles or quaternions. By selecting an attitude error function
carefully, we show that the proposed control system guarantees a desirable
tracking performance uniformly for nontrivial rotational maneuvers involving a
large initial attitude error. In a special case where the desired attitude
command is fixed, we also show that the attitude dynamics can be stabilized
without the knowledge of an inertia matrix. These are illustrated by numerical
examples.
