Heliogyro Attitude Control Moment Authority via Blade Pitch Maneuvers

Heliogyros generate attitude control moments by pitching their sail membrane blades collectively or cyclically, similar to a helicopter. Past work has focused on simple blade pitch profiles with the heliogyro normal to the sun; however, most solar sail missions will require sun angles of at least 35°. Furthermore, combination pitch profiles (e.g. cyclic plus collective) are needed for attitude control during all mission segments. The control moments for such situations vary in an unintuitive, nonlinear fashion. This paper explores heliogyro control moment authority with varying sun angle and combinations of pitch profiles, providing critical insight for future development of heliogyro attitude control schemes. Three strategies for generating control moments using various profile combinations are investigated for three-axis attitude control. These strategies indicate that the heliogyro can generate control moments while edge-on to the sun, allowing for recovery from any orientation. A control algorithm is presented that determines the required blade pitch profile combination to generate the desired attitude control torques. This algorithm could be employed for closed-loop control in attitude dynamics simulations.