Shape Adjustment of a Flexible Space Antenna Reflector

Abstract

A recursive shape adjustment algorithm is proposed, which will be used for flexible antenna reflectors for space application. The antenna reflector is composed of flexible mesh surface, cable networks, and support structures. Length adjustment mechanisms are attached to the suspension wire between the surface cable and the backup network, and the shape of the mesh surface is controlled by the adjustment mechanisms. For the purpose of effective adjustment, the matrix of influence coefficients (sensitivity matrix) of the adjustment length to the surface displacements is needed, and the matrix is usually calculated by analytical model. But some modeling errors, such as prediction error of material properties or error due to model simplification, are unavoidable in the preliminary analysis. Besides, the sensitivity matrix may change during the process of adjustment because of nonlinearity of the structure in some cases. To avoid the above problems, a recursive shape adjustment algorithm is proposed. The major characteristic of the algorithm is the recursive modification of the sensitivity matrix based on the be havior of the system in the iterative adjustment. Using this algorithm, the modeling error is automatically corrected in the adjustment process and the procedure will converge efficiently. The effectiveness of the algorithm is confirmed by numerical simulations and an experiment using a model of a large antenna reflector. Since this algorithm allows the change or modeling error of structural sensitivity, it shall also be useful for the on-board shape control of flexible reflectors.