On the joint design and hydraulic actuation of octahedron VGT robot manipulators

In this paper, the design for variable geometry truss manipulators, with 3-DOF octahedron-shaped modules and hydraulic actuation is introduced. The main features of the concept are the optimized multiple collocated spherical joints and a structure-integrated supply of the drive fluid for the hydraulic actuators. Based upon the known Spherical Joint Mechanism, design rules are deduced and modified joint elements are presented to provide a larger workspace for a single module. The potential of the resulting module design is demonstrated by the calculation of the workspace, as well as the payload-to-mass ratio. Based upon the presented results, a family of highly maneuverable light-weight hyper-redundant manipulators can be derived.