Steering law of control moment gyros using optimization of initial gimbal angles for satellite attitude control

Control Moment Gyros (CMGs) has been expected to be applied to an earth observing satellite in recent years. However it is not easy to control it because CMGs has a singularity condition and a major source of disturbance. Although there are many singularity avoidance logics, these optimal methods from the viewpoint of singularity avoidance may cause inner disturbance by fast and furious motion of gimbals in avoiding singularity. From the previous background, this paper presents a new but simple CMGs steering law using preferred initial gimbal angles and null motion for high accurate attitude control system on an agile satellite. Preferred initial gimbal angles are decided by evaluating function considering inner state of CMGs.