Observer Modal Control of Dual-Spin Flexible Spacecraft

A procedure is presented for the control of a dual-spin spacecraft consisting of a spinning rigid rotor and a flexible despun section. Such a system exhibits gyroscopic effects. The system equations of motion are uncoupled by using gyroscopic modal analysis and the active control of the spacecraft is accomplished by synthesizing the control on the independent spacecraft modes. A deterministic (Luenberger-type) observer is designed by using decoupled dynamics and inserted in the control loop, where the control operates on an on-off scheme. Proportional control representing classical linear feedback approach is also discussed. Finally, the relation between spatially distributed actuators and modal control is discussed.