Variable geometry truss and its application to deployable truss and space crane arm

Abstract

The purpose of this paper is to describe the variable-geometry-truss concept and to discuss its applications to deployable linear and curvilinear trusses and a manipulator arm. The variable geometry truss consists of the repetition of an octahedral truss module longitudinally. The geometrical transformation of an octahedron is the basis of the present concept. The principal mechanical feature of the truss is that the lateral members of the truss are variable length beams, while the diagonal members are fixed length beams. Through such mechanisms, the truss can be transformed to varieties of configurations. Both simultaneous and sequential modes for transformation, that is, deployment are shown. An application of the concept to a manipulator arm having multiple degrees of freedom is discussed. The resulting VGT-manipulator can be programmed to retreat and deploy and take a position in any desired configuration. The basic kinematic geometry of the VGT manipulator is established.