Disturbance observer-based attitude control of spacecraft with single-gimbal control moment gyros

This paper investigates the attitude control problem of spacecraft with single-gimbal control moment gyro (SGCMG). Firstly, a disturbance observer is given. Then, a control law, integrated disturbance observer with backstepping integral sliding mode control (ISMC), is developed to achieve spacecraft attitude stabilization. System uncertainties and external disturbances are compensated by the disturbance observer. The Lyapunov stability approach has been applied to the analysis of the disturbance observer and the control law for the concerned system. Simulation results for the spacecraft show that a fairly good control performance is achieved in the presence of system uncertainties and external disturbances.