DETUMBLING AND REORIENTATION MANEUVERS AND STABILIZATION OF NASA SCOLE SYSTEM

The question of rotational maneuver and vibration stabilization of the NASA Spacecraft Control Laboratory Experiment (SCOLE) system is considered. The mathematical model of the SCOLE system includes the rigid body dynamics as well as the elastic dynamics representing transverse and torsional deformations of the elastic beam connecting the orbiter and end body (reflector). For the rotational maneuver, a new control law (orbiter control law) is derived using an orbiter input torque vector. Using this control law detumbling and reorientation maneuvers of the SCOLE system are accomplished, however, this excites the elastic modes of the beam. Interestingly the orbiter control law asymptotically linearizes the flexible dynamics. Using the linearized model, a linear feedback control law is designed for vibration suppression. An observer is designed for estimating the state variables using sensor outputs which are also used for the synthesis of the control low. Simulation results are presented to show that in the closed-loop system detumbling and reorientation maneuvers can be accomplished and the effect of control and observation spillover is insignificant.