  Soft robots are capable of inherently safer interactions with their
environment than rigid robots since they can mechanically deform in response to
unanticipated stimuli. However, their complex mechanics can make planning and
control difficult, particularly with tasks such as locomotion. In this work, we
present a mobile and untethered underwater crawling soft robot, PATRICK, paired
with a testbed that demonstrates closed-loop locomotion planning. PATRICK is
inspired by the brittle star, with five flexible legs actuated by a total of 20
shape-memory alloy (SMA) wires, providing a rich variety of possible motions
via its large input space. We propose a motion planning infrastructure based on
a simple set of PATRICK's motion primitives, and provide experiments showing
that the planner can command the robot to locomote to a goal state. These
experiments contribute the first examples of closed-loop, state-space goal
seeking of an underwater, untethered, soft crawling robot, and make progress
towards full autonomy of soft mobile robotic systems.
