  Truss robots are highly redundant parallel robotic systems that can be
applied in a variety of scenarios. The variable topology truss (VTT) is a class
of modular truss robots. As self-reconfigurable modular robots, a VTT is
composed of many edge modules that can be rearranged into various structures
depending on the task. These robots change their shape by not only controlling
joint positions as with fixed morphology robots, but also reconfiguring the
connectivity between truss members in order to change their topology. The
motion planning problem for VTT robots is difficult due to their varying
morphology, high dimensionality, the high likelihood for self-collision, and
complex motion constraints. In this paper, a new motion planning framework to
dramatically alter the structure of a VTT is presented. It can also be used to
solve locomotion tasks that are much more efficient compared with previous
work. Several test scenarios are used to show its effectiveness. Supplementary
materials are available at https://www.modlabupenn.org/vtt-motion-planning/.
