Dynamics and control of a large deployable reflector

The problem of passively controlling structural deformations in a large deployable reflector by adding damping to the system is reviewed. The results of modeling a large deployable reflector with PATRAN-G and analysing it with EASE2 and MSC/NASTRAN finite element codes are reported. The first ten asymmetric and symmetric mode shapes and natural frequencies are determined. The application of symmetry and the replacement of the mirror reflectors with lumped masses enables a substantial reduction in the amount of computer time to be achieved without loss of accuracy. Following identification of the dynamic characteristics of the structure, sensitivity analyses enable determination to be made of the optimal placement of passive damping elements to decrease the structural deformations of the reflector structure.