  Truss robots, or robots that consist of extensible links connected at
universal joints, are often designed with modular physical components but
require centralized control techniques. This paper presents a distributed
control technique for truss robots. The truss robot is viewed as a collective,
where each individual node of the robot is capable of measuring the lengths of
the neighboring edges, communicating with a subset of the other nodes, and
computing and executing its own control actions with its connected edges.
Through an iterative distributed optimization, the individual members utilize
local information to converge on a global estimate of the robot's state, and
then coordinate their planned motion to achieve desired global behavior. This
distributed optimization is based on a consensus alternating direction method
of multipliers framework. This distributed algorithm is then adapted to control
an isoperimetric truss robot, and the distributed algorithm is used in an
experimental demonstration. The demonstration allows a user to broadcast
commands to a single node of the robot, which then ensures the coordinated
motion of all other nodes to achieve the desired global motion.
