Fold Process for Precise Retraction of Deployable Space Membrane

Abstract

A fold process of a deployable space membrane with retraction mechanisms is examined to reduce wrinkles and to improve the fold precision of the membrane retracted repeatedly. The properties of the fold process are investigated experimentally with experimental retraction mechanisms which wrap and fold the membrane with tensile forces and rotation of the center hub. To reduce wrinkles, and to improve the fold precision, hinge mechanisms which are stiffened elements attached on the membrane are proposed. To examine the effects of the hinge mechanisms, fold patterns, and configuration of the center hub on the properties of the fold process, the retraction experiments are performed. The experimental results indicate that the distribution of the tensile forces and the hinge mechanisms mainly determine the fold process. Introducing the mixed spiral fold which consists of Z-folds and spiral folds, the membrane is successfully folded with fewer wrinkles and higher precision than the rotationally skew fold.