Robust Attitude Tracking Control Based on Adaptive Dynamic Programming for Flexible Dumbbell-Shaped Spacecraft

In this paper, a robust attitude tracking controller is designed for a dumbbell-shaped flexible spacecraft (D-SFS) subject to actuator saturation and the velocity constraint of attitude maneuver, based on adaptive dynamic programming (ADP). The proposed method can effectively solve the attitude tracking control problem in the process of low-thrust orbit transfer (LTOT) with guaranteeing a nearly optimal cost. Firstly, by constructing a nonlinear sliding mode (SM) structure involving the angular velocity constraint, the dynamic model of the D-SFS can be transformed into a nonlinear affine system. Secondly, a non-quadratic cost function based on the nonlinear SM structure is proposed, taking into account the actuator saturation. The ADP technique is then employed, along with an adaptive robust term, to ensure nearly optimal cost and suppress the effect of input disturbance. Thirdly, the Lyapunov method is utilized to analyze the stability of the D-SFS. Finally, numerical simulations are provided to verify the effectiveness of the proposed theoretical results.