  There has been increasing awareness of the difficulties in reaching and
extracting people from mass casualty scenarios, such as those arising from
natural disasters. While platforms have been designed to consider reaching
casualties and even carrying them out of harm's way, the challenge of
repositioning a casualty from its found configuration to one suitable for
extraction has not been explicitly explored. Furthermore, this planning problem
needs to incorporate biomechanical safety considerations for the casualty.
Thus, we present a first solution to biomechanically safe trajectory generation
for repositioning limbs of unconscious human casualties. We describe
biomechanical safety as mathematical constraints, mechanical descriptions of
the dynamics for the robot-human coupled system, and the planning and
trajectory optimization process that considers this coupled and constrained
system. We finally evaluate our approach over several variations of the problem
and demonstrate it on a real robot and human subject. This work provides a
crucial part of search and rescue that can be used in conjunction with past and
present works involving robots and vision systems designed for search and
rescue.
