Abstract:

For a spacecraft using single gimbal control moment gyros (SGCMGs) as actuators, taking the spacecraft and SGCMGs as a whole system, the model of the attitude control system is constructed in the gravitational field by using Lagrangian and Hamilton equations. In the case of largeangle maneuvers of the spacecraft in short time, the state equation of the system in Lagrangian form is simplified as an affine nonlinear equation, with the angular velocity of SGCMG gimbals as an input variables, which avoids the singularity problem arising in conventional treatment. Finally, the controllability of the system is analyzed by using the preservation of the system volume in Hamiltonian form. The controllability property holds in spite of the number of the SGCMGs, their configuration and the presence of singularity. The model and the controllability of the attitude control system provide a theoretical basis of the further investigation on the control and stability analysis of the spacecraft system.