Abstract: Spatial polyhedral linkages mechanism along radial axes is one of special kinds of deployable and foldable mechanism. The shape of this kind of mechanism is usually sphere or polyhedron and highly symmetrical. It can be deployed or folded through the joints rotating. Based on the structural and movement characteristics of this kind of radial mechanism, a new hexahedron mechanism is proposed. This mechanism is assembled by 4 four-legged platforms and 1 cross slider. Its mobility and singularity are analyzed on the basis of screw theory. By using this novel hexahedron mechanism, a new synchronously deployable mast is developed, whose mobility is single. The kinematics and dynamics are studied and their equations are derived. It is helpful for the analysis and design of this mast. At last, the correctness of the equations are verified by comparison between the results of derived equations and ADAMS simulation. This kind of mast has good prospects of application in space field.

Key words: Deployable mechanism, Dynamics, Kinematics, Mast, Radial mechanism, Screw theory