Non-linear Momentum and Attitude Control of a Space Station Accommodating Periodic Aerodynamic Disturbance

This paper considers non-linear regulation and angular momenta management of a Space Station in the presence of a disturbance torque. The sinusoidal aerodynamic disturbance torque is treated as the output of an exosystem. An output zeroing submanifold for the regulation of pitch angle and roll and yaw axis control moment gyro (CMG) angular momenta is obtained. A control law is derived such that in the closed-loop system the trajectories converge to this manifold and the desired equilibrium state is attained. For the synthesis of the controller, the states associated with the exosystem are generated using measurements of the attitude angles and angular rates. Simulation results are presented to show that in the closed-loop system, pitch attitude regulation and CMG momenta management are accomplished in spite of the presence of the aerodynamic disturbance inputs and parameter uncertainty