Attitude Maneuver and Stability Control of Hyper-Agile Satellite Using Reconfigurable Control Moment Gyros

Addressing the problems of insurmountable unknown frictional disturbance and balancing the trade-off between high maneuverability and stability during attitude maneuver are important in low-cost miniaturized single control moment gyro clusters (SGCMGs) for hyper-agile satellite. This paper proposes a new concept of reconfigurable octagonal cone-type SGCMGs by considering practical engineering requirements of hyper-agile satellites. Firstly, the momentum characteristics of typical configurations are quantitatively explained, and the evaluation metrics for SGCMGs based on norm $L_{\infty }$ and norm $L_2$ are defined, respectively. Secondly, a reconfiguration design of SGCMGs from octagonal cone-type into pyramid-type is proposed by analyzing the unknown disturbance mechanism based on SGCMGs. When the hyper-agile satellite is supported to perform fast attitude maneuvers, all units of SGCMGs can work together to output rough and large torque. On the other hand, when the maneuvering ends with stable pointing control, gimbles of one pyramid-type SGCMGs are locked down and fine torque is outputted using another pyramid-type SGCMGs. This will greatly reduce the difficulty of controller design and improve the satellite attitude performance indices. The superiority of the control strategy and selection of the proposed actuator is verified by experiments.