Time-Optimal Reorientation of a Spacecraft Using an Inverse Dynamics Optimization Method

This paper proposes a rapid attitude trajectory generation method for satellite reorientation, which is suitable for both rest-to-rest and track-to-track maneuvers. The problem is first formulated and solved using academic software readily used for generating optimal guidance trajectories offline. Then, the problem is reformulated using a Bezier polynomial parametrization of the quaternion trajectory, which naturally satisfies the unit quaternion norm constraint. The parameters of the quaternion trajectory polynomial and of the speed profile are varied to arrive at a quasi-optimal solution that is both feasible and exactly matches the endpoint conditions specified in the problem. The reduction in the number of varied parameters due to the predetermined structure of the trajectory leads to a fast computational speed as well as a solution that satisfies the end constraints at each iteration. The paper includes numerical simulation results obtained for several cases.