Dynamic modeling and attitude control of flexible solar sail spacecraft for deep space exploration

The solar radiation pressure is used by solar sail to provide the necessary power for space navigation. Because of its infinite speed and no consumption of any fuel theoretically, it is considered as one of the most effective ways for future deep space exploration missions. The dynamics model of flexible solar sail spacecraft including multi-body dynamics, rigidflexible coupling dynamics and solar radiation pressure makes the attitude control design very challenging. In this paper, for a flexible solar sail spacecraft with a control boom, a control-oriented analytical model is derived by the Lagrange equation and finite element method. The deduced rigid-flexible coupling dynamics model characterizes the essential dynamics properties of the short-term motion of a two-axis gimbaled control boom, the coupling properties between attitude and flexible sail, and the long-term movement of statically stable attitude under solar pressure restoring torque. Based on the dual-time-scale property of the solar sail spacecraft with a control boom, a dual-loop control structure is proposed to change the pitch-axis and yaw-axis attitudes of the spacecraft by employing a gimbaled control boom. The inner-loop is designed as a proportional-derivative (PD) controller to realize the regulation of the center of mass. The outer-loop is intended to be a proportional-integral-derivative (PID) controller to damp the oscillating motion and maintain the desired attitude under balanced solar radiation pressure torque. Consequently, the full control problem is decomposed into two lowerorder subproblems, which are solved at different frequency bands. Finally, simulation results are presented to validate the dynamic modeling and attitude control approach. © 2019, Editorial Department of Control Theory & Applications. All right reserved.