Soft Robotic Manipulators Inspired by the Fin Ray Effect
Abstract: As robots
become increasingly ingrained in our lives, we need to find ways to ensure that these
robots are safe for human interaction. In this dissertation, I present two soft robotic
manipulators: The Tufts Active Gripper (TAG) and the Tufts Passive Gripper (TPG). Both
grippers are predominantly soft and inspired by the Fin Ray Effect, a structure based on
the deformation of fish ... read morefins. It was discovered that modifying the angle of the
crossbeams of the Fin Ray geometry with respect to the base resulted in a preferred
bending direction. This angle was optimized through FEA analysis and a set of equations
to describe the Fin Ray Effect were developed. This optimization was used in the final
designs of TAG, an active gripper that requires power to maintain grip on an object, and
TPG, a passive gripper inspired by the Manduca sexta that requires power to open and
close but not to maintain grip. TAG and TPG are both 3D printed as one part, require
under 5 steps to attach their motor/tendon actuation systems, and can both be produced
and outfitted with electronics for under $200. The load capacity of TAG and TPG were
tested. Both can hold approximately 550 g in a vertical orientation, but TAG can hold
twice as much as TPG in the horizontal orientation (390 g vs 240 g, respectively). This
discrepancy is likely due to differences in the designs that were necessary to make a
passive gripper, for example a smaller number of supports in the TPG that were meant to
prevent unwanted deformation. The TAG and TPG also exerted normal forces differently,
with the highest normal forces for TAG at the tip and base and the highest for TPG in
the middle. TAG and TPG were both capable of holding a wide range of objects, but it was
easiest to hold cylindrical objects and hardest to hold long, thin objects. Future
versions of both grippers should improve load capacity and reduce
Thesis (Ph.D.)--Tufts University, 2017.
Submitted to the Dept. of Mechanical Engineering.
Advisor: Chris Rogers.
Committee: William Messner, Barry Trimmer, and Andy Levine.
Keywords: Robotics, and Mechanical engineering.read less