An actuated platform FEA model used for precision pointing control

A large, segmented space telescope requires high precision and accuracy in its mirror shape to obtain clear images. The Structures, Propulsion, and Control Engineering (SPACE) telescope testbed at the NASA sponsored University Research Center must maintain a pointing control accuracy of 2 arc seconds. A Peripheral Pointing Architecture (PPA) has been designed to demonstrate the testbed pointing accuracy. A finite element model of the PPA is developed. Normal mode analysis is performed to establish the PPA's natural frequencies, mode shapes, mass and stiffness matrices. Utilizing H-infinity controllers developed for figure maintenance, the pointing control of the testbed structure is achieved.