Analysis of the inertially symmetric rigid spacecraft time-optimal three-axis reorientation.

This paper investigates the classical time-optimal rest-to-rest three-axis reorientation of the inertially symmetric rigid spacecraft. First-order necessary optimality conditions are derived from the Pontryagin's maximum principle. Then, control structures (i.e., switching times and control torques) for the time-optimal solution with five, six, and seven switches are given. For any five-switch, six-switch, or seven-switch time-optimal solution, a finite number of control structures exist, and relations among the control structures and their associated time-optimal solutions are analytically derived. By utilizing the control structure, efficient numerical optimization algorithm based on multiple-interval Radau pseudospectral method is proposed. Numerical results show that, after rounding to integer, five-switch and six-switch time-optimal solutions exist for rotation angles on the interval [1,180] deg, and s es on the interval [1,72] deg. Finally, time-optimal solutions for typical rotation angles are given to illustrate and validate the new findings. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]