Robust H-infinity control design for spacecrafts with large flexible netted antennas

To deal with the flexible structure uncertainty of the spacecrafts with a large flexible netted antenna, we propose a robust H-infinity double feedback controller based on a typical proportional and derivative (PD) controller with structure filters. The first layer of the controller is built with a typical PD controller with structure filters to ensure the stability of the second-order integral system of the rigid part of the spacecraft. Based on the normal model obtained from the closed system with the first layer control, we give the general form of weight functions and construct the incremental model for designing the robust H-infinity controller which is called the second layer controller. The proposed robust controller is suitable for spacecrafts with momentum wheels. It is shown by simulations that the given method provides rapid stabilization for three-axis attitude control, and is more robust than the typical PID controller in performing the center-pointing task of the flexible antenna.