GENERAL ATTITUDE MANEUVERS OF SPACECRAFT WITH FLEXIBLE STRUCTURES

An efficient composite control strategy is proposed in this paper perm itting simultaneous multi-axis reorientation of a spacecraft with flex ible structures. The proposed control, separating large and small moti ons of the dynamic system, includes three parts that can be independen tly designed and tuned. For each maneuver, an open-loop referencing at titude control trajectory is derived by considering the spacecraft as rigid and executed by part 1. Flexural deformations of the structures are stabilized by part 2. Part 3, encompassing part 1 and part 2 contr ol results and external disturbances, is an optimal guidance that trac ks part 1 reference trajectory and achieves the specified final attitu de in finite time. Three simulation cases are included in which a flex ible model spacecraft is used. Collocated actuators and sensors are pl aced on the hub and on the flexible structures of the spacecraft.