  In the field of soft robotics, flexibility, adaptability, and functionality
define a new era of robotic systems that can safely deform, reach, and grasp.
To optimize the design of soft robotic systems, it is critical to understand
their configuration space and full range of motion across a wide variety of
design parameters. Here we integrate extreme mechanics and soft robotics to
provide quantitative insights into the design of bio-inspired soft slender
manipulators using the concept of reachability clouds. For a minimal
three-actuator design inspired by the elephant trunk, we establish an efficient
and robust reduced-order method to generate reachability clouds of almost half
a million points each to visualize the accessible workspace of a wide variety
of manipulator designs. We generate an atlas of 256 reachability clouds by
systematically varying the key design parameters including the fiber count,
revolution, tapering angle, and activation magnitude. Our results demonstrate
that reachability clouds not only offer an immediately clear perspective into
the inverse problem of control, but also introduce powerful metrics to
characterize reachable volumes, unreachable regions, and actuator redundancy to
quantify the performance of soft slender robots. Our study provides new
insights into the design of soft robotic systems with minimal activation and
maximal reach with potential applications in medical robotics, flexible
manufacturing, and the autonomous exploration of space.
