Nonlinear Modeling and Surface Mounting Optimization for Extremely Large Deployable Mesh Antenna Reflectors

Abstract

Adaptive Surface Control (ASC) technologies are being developed to enable extremely large deployable high RF mesh antenna reflectors for future NASA missions. This paper presents the results that are obtained from an initial study on the ASC technologies for the mesh reflector. A three-dimensional nonlinear truss model is developed to describe large deformation of the reflector during deployment. The deployment process of the reflector involves mounting a network of truss elements on a rigid frame through use of tension ties. An initial profile of the undeformed truss structure is to be determined to achieve required surface accuracy after deployment. The mathematical description of this surface mounting leads to a nonlinear optimization problem. An iterative algorithm is devised to obtain the initial profile of the undeformed reflector. The proposed model and surface optimization algorithm are applied to an 835-node reflector. Numerical simulation shows that the algorithm converges fast at low computational costs, and that the solutions obtained are accurate to computer’s digits. The reflector model and surface optimization algorithm are readily applicable to adaptive surface control of the antenna reflector under thermal loads.