The Inverse Kinematic Solution of the Tetrahedron Based Variable-Geometry Truss Manipulator

The Tetrahedron Based Variable Geometry Truss Manipulator is comprised of a series of tetrahedrons stacked upon one another in a spiraling manner. When one link of each “cell” is made variable in length, the system can be effectively used as a remote manipulator. The manipulator is kinematically equivalent to a serial link manipulator consisting only of revolute joints where the angle between successive axes is 120°. In this paper, a closed-form analytic solution for the six-celled (6R series) variable geometry truss manipulator is obtained. It is shown that a sixteenth order polynomial in one of the joint angles is found which leads to at most sixteen solutions.