Large light-weight deployable cable net reflectors are widely used in communication satellites. These are much larger than satellite and need stowing into a relatively small volume to fit into launch vehicle and are deployed in orbit. The cable net reflectors use deployable support structure along with pretensioned cable net. Due to its large dimensions, the deployed natural frequency will be quite low and may not be acceptable from controls point of view. In such cases, the deployed frequency needs to be enhanced to ensure that the same meets the minimum requirements. This article presents a study of the different parameters, which have been varied in order to assess the sensitivity of the same with respect to the deployed frequency. The effect of the flexibility of each sub-assembly has been assumed and this has helped to identify the sub-assembly, which has to be stiffened in order to enhance the overall frequency. Also, the results from this study have provided the design inputs for modifications to be carried out in order to realize a large cable net antenna.
The equations of motion of a deploying solar array are derived using Lagrange's method and solved numerically. With increase in the number of panels, the mathematical modelling becomes complicated, invo1ving the derivation of lengthy equations which can be error prone. A matrix approach has been adopted for automatic derivation of lengthy equations of motion. This facilitates the accommodation of n panel formulation by increasing the number of rows and columns. The complexity in derivation of the air drag and damper are discussed here. NOTATION A p projected area (m 2 ) B r width of the panel (m) c prerotation angle of the torsion springs (rad) C d drag coef cient i, j subscripts de ning the yoke and the panels 1 4 …i; j † 4 n I mass moment of inertia (kg m 2 ) K stiffness of the spring (N m/rad) K c stiffness of the Closed Control Loop (CCL) springs (N/m) ‰KŠ generalized stiffness matrix K T stiffness of the torsion spring at each hinge line (N m/rad) l length of the yoke and panels (m) L Lagrangian …T ¡ U † m mass of the yoke and panels (kg) ‰M Š generalized inertia matrix n number of panels ‰N Š Coriolis/centripetal acceleration matrix q generalized coordinates (rad) _ q q rst derivative of q with respect to time (rad/s) q q second derivative of q with respect to time (rad/s 2 ) fQ i g generalized force vector (N m) R p radius of the CCL pulley (m) t time (s) T total kinetic energy of the system (N m) U total potential energy of the system (N m) U c potential energy of the CCL pulley (N m) v system velocities (m/s) x distance from the hinge line to the elemental strip (m) dW total virtual work (N m) r density of air (kg/m 3 )
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.