Feedforward and feedback control for flexible spacecraft based on perturbation estimation

A feedforward and feedback control method for rest-to-rest maneuvers of flexible spacecraft is presented, with the objective insensitivity to modeling errors, parameter uncertainty, and minimizing the residual energy of the flexible modes. The feedforward control law is based on perturbation estimation, input-shaping design, and the use of basic conditions of the rigid-body modes with additional final conditions, i.e. zero-coupling moment and zero-coupling moment-derivative, which lead to forming of a boundary-value problem, and solved using an update algorithm. The feedback control law was proposed to gain the desired attitude, which designed for the rigid body modes. The capability of this design is demonstrated through a numerical example in which with the proposed method, there is able to eliminate the residual energy and robust to modeling errors.