Time-Optimal Attitude Reorientation at Constant Angular Velocity Magnitude with Bounded Angular Acceleration

This paper considers the problem of steering the orientation of an inertially symmetric rigid body of unit moment of inertia from an initial attitude and nonzero angular velocity to a specified terminal attitude in minimum time under an upper limit on the magnitude of angular acceleration with the magnitude of the angular velocity constrained to remain constant. Optimal control theory is used to show that singular optimal arcs are uniform eigenaxis rotations in which the body rotates at a uniform rate about a body-fixed axis, while nonsingular arcs are coning motions in which the body angular velocity vector rotates at a uniform rate about a body-fixed axis. Symmetries of the problem are exploited to further show that every optimal trajectory consists of at most one coning motion followed either by one uniform eigenaxis rotation or several coning motions of equal duration