Inverse optimal and robust nonlinear attitude control of rigid spacecraft

This paper presents a novel inverse optimal and robust nonlinear attitude control law using the attitude quaternion feedback for regulation of rigid spacecraft. The attitude control law proposed in this paper has optimality with respect to a performance index incorporating a positive penalty on both the angular position and velocity and the control torque. Also, it has robustness with respect to control input uncertainties described as the output of a state strictly passive system and belonging to a sector. The result of the paper is illustrated by numerical simulations.