Design of an attitude control system by multi objective optimization considering practical operation of spacecraft equipped with control moment gyros

Recent years have seen a growing requirement for accurate and agile attitude control of spacecraft. To both quickly and accurately control the attitude of a spacecraft, Control Moment Gyros (CMGs) which can generate much higher torque than conventional spacecraft actuators are used as actuators of the spacecraft. Rapid maneuverability is needed for spacecraft with CMGs, which requires the drive from motors. Given the drive from motors negatively affects their lifetime, the attitude control system should ensure a long operating life for CMGs by reducing the drive from the motors. Thus, the conflicting requirements of rapid maneuverability and a long operating life for CMGs are needed. In this study, multi-objective optimization of the Skew angle and parameters of the control system considering conflicting requirements is proposed. The Pareto solutions are obtained using optimization of the parameters. As a specific design method, the settling time and motion of gimbal axes are evaluation criteria when considering rapid maneuverability and the life time of CMGs. Using numerical analysis, it is shown that the settling time and drive on the gimbal can be shorter by optimizing the Skew angle, and the appropriate Skew angle can be designed to meet the requirements of the mission. The changes in parameters as a function of the drive on the gimbal, in addition to settling time, are established.