Fully-Coupled Dynamical Jitter Modeling Of A Rigid Spacecraft With Imbalanced Double-Gimbal Variable-Speed Control Moment Gyros

摘要

Much attention has been paid to a double-gimbal variable-speed control moment gyro (DGVSCMG) as three-dimensional torque generator. However, since this device typically operate at high wheel speeds, mass imbalances within the wheels act as a primary source of angular jitter. An estimate of jitter amplitude may be found by modeling imbalance torques as external disturbance forces and torques on the spacecraft. In this case, mass imbalances are lumped into static and dynamic imbalance parameters, allowing jitter force and torque to be simply proportional to wheel speed squared. A physically realistic dynamic model may be obtained by defining mass imbalances in terms of a wheel center of mass location and inertia tensor. The fully-coupled dynamic model allows for momentum and energy validation of the system. This paper presents a generalized approach to DGVSCMG imbalance modeling of a rigid spacecraft hub with n DGVSCMGs. Through the numerical simulations, the effectiveness of the proposed dynamic model is demonstrated.