Spacecraft Attitude Control Compensating Internal Payload Motion Using Disturbance Observer Technique

Abstract

Spacecraft attitude motion compensation approach to deal with internal slewing payload motion is addressed in this study. The internal payload motion is generated by a steering mechanism such as steerable gimbals for image acquisition as well as error correction due to orbital and attitude errors. Disturbance caused by payload motion in general cannot be measured using sensing devices. The disturbance effect can be estimated by using the so-called disturbance observer technique. The estimated disturbance can be compensated by a feedforward control law. The new control law can accommodate internal disturbance by a combined conventional feedback and feedforward control for estimated disturbance.