Robust Model Predictive Attitude Control of Large Flexible Spacecraft

Considering the three-axis attitude control problem of a large flexible spacecraft with control input constraints, a robust model predictive attitude controller is designed. The model predictive control is applied to the nominal flexible spacecraft system without considering the disturbance. The predictive control law is derived by solving the optimization problem, and the nominal trajectory of the three-axis attitude is obtained. In order to effectively deal with the disturbance of the central rigid body attitude caused by the vibration of the large flexible appendages, the auxiliary feedback controller composed of the error between the optimal state and the actual attitude control system state is designed for the actual system of the flexible spacecraft with disturbances. The actual system state is maintained within the Tube invariant set centered on the nominal trajectory, and is driven to reach the nominal trajectory, and finally converges to the equilibrium point. The simulation results show that under the action of the robust model predictive control, the rapid and accurate tracking of the attitude angle is realized. The disturbance of the central rigid body attitude caused by the vibration of large flexible appendages is effectively rejected, and the robustness of the system is enhanced. © 2022, Editorial Dept. of JA. All right reserved.