Simulation of Actively Controlled Spacecraft with Flexible Appendages

Complex interplanetary spacecraft and newly proposed satellites for reconnaissance and strategic defense are being designed with increasingly light and flexible appendages despite ever more demanding requirements for accurate pointing and tracking. The onboard control systems required to satisfy these strict requirements during reasonably quiescent conditions must also act effectively to limit deformation and maintain stability of motion in the face of significant disturbances to flexible appendage motion resulting from spin-up, spin-down, orbital, and deployment maneuvers of various types. This paper incorporates a recently proposed theory for modeling flexible bodies into a framework for studying the effects of beamlike appendage deformation on overall system performance. Illustrative examples involving use of the theory hi practical applications are presented, and relative merits of this model theory vs nonlinear finite-element techniques are discussed.