The Folding Course for the Tensegrity Basic Unit

The tensegrity structure with characteristics of light weight and little compression volume is a hot spot for research in architecture and spaceflight. The tensegrity basic unit is the foundation of other tensegrity structure. The tensegrity basic unit is analyzed in the text in order to provide methods for research on other tensegrity structure. At first, node coordinates of the nodes and connectivity matrix are adopted to set up the math expressions of vectors of all the bars and strings. After structural characteristics of the tensegrity basic unit are analyzed, the two folding methods are presented. The driving method where lengths of all the bars are constant and the level strings are shortened to fold the structure is analyzed in detail. Changes of length, velocity and acceleration of every member are researched in the course of folding the structure. Geometrical relationships among the members are adopted to set up the equilibrium equations of the nodes. With the equations, changes for the internal forces of all members are computed in the folding course of the structure. Applications of the folding methods to a tensegrity mast are researched. Through analysis in the text, methods for setting up math model of the tensegrity basic unit and folding it are obtained. The methods obtained in the text can be applied as a reference to research on other tensegrity structures.