Push-Pull Pair of Single Action Mechanisms to Preload Strut and Node Joints in the Robotic Assembly of Structures in Space

Abstract

Abstract When strut and node components are used for truss construction or repair, an assembly problem occurs if a strut must fit between nodes whose separation distance is either more or less than the design specification. In such circumstances two actions would permit continued assembly: 1. Change strut length 2. Move the nodes. Variable length struts fit between nodes and (or) move them. They are preloaded at the joint against a reference length in an attempt to maintain the desired dimension. As a by-product they either pull the nodes together or push them apart. Most cannot do both, and are therefore characterized as “single action”; those that can do both are “double action”. Double action mechanisms are currently being used for robotic truss assembly because they solve the above stated crucial problem in both directions. Single action mechanisms tend to exhibit superior performance in all other categories. They benefit from the attributes that accompany their simplicity. The titled concept combines the major advantage of double action with the simplicity of single action. This is demonstrated with an example.