Deployable structure of curved profile for space antennas

In the past, deployable structural mechanisms made from pantographic elements of straight struts could form only certain shapes because of restrictions imposed by geometric compatibility conditions, which prohibit the concepts from being used in applications such as antenna reflectors where nodes of the structure usually lie on a parabolic surface. This paper presents a generic solution for construction of deployable structures in any shape of rotational symmetry. The structures have an internal degree of mobility. The key difference between this new concept and the others is the introduction of a novel type of intermediate element consisting of two ordinary pantographic elements, which provides far greater freedom in designing the shape of the structure while structural mobility is intact. Furthermore, the intermediate element can be added into any existing deployable pantographic structure to increase the overall stiffness while retaining its ability of deployment. This paper gives full geometric proof, together with a design for joints. The concept can be extended into other structural forms. This type of structure can be used as the backbone of deployable antennas or shelters in space.