Steering Law of Control Moment Gyros using Optimization of Initial Gimbal Angles for Satellite Attitude Control

Control Moment Gyroscope (CMG) has been expected to be applied to a spacecraft such as an earth observation satellite in recent years. However it is not easy to control it because CMG 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. This paper presents a new but simple CMG steering law using preferred initial gimbal angles and null motion for high accurate attitude control system on an agile spacecraft. The preferred initial gimbal angles are decided by evaluating function considering inner state of CMG. From the simulation results, the effectiveness of the proposed method was verified.