Page 9 - ASME SMASIS 2016 Program

Symposia

SYMPOSIUM 1 SYMPOSIUM 2

SOFT ROBOTICS: DESIGN AND FABRICATION OF INTELLIGENT BIOINSPIRED ADAPTIVELY RECONFIGURABLE MATERIALS FOR
MATERIAL SYSTEMS ARTIFICIAL HOMEOSTASIS AND ARTIFICIAL PHOTOTROPISM

Rebecca Kramer Ximin He
Purdue University Materials Science and Engineering
West Lafayette, IN Arizona State University
Phoenix, AZ

Abstract Abstract
As advanced as modern machines are, the building blocks have changed Living organisms exhibit unique homeostatic abilities, maintaining tight
little since the Industrial Revolution: structures, motors and gears are control of their local environment. These functions all rely on cascade
typically rigid, bulky and heavy. In contrast, soft robots offer the compli- chemical and mechanical energy transduction. Inspired by this we
ance and low-weight necessary to make them safe for working in close developed the first artificial homeostatic material systems which can
proximity to humans, as well as allowing them to squeeze into tight spaces, autonomously self-regulate local condition via a built-in chemo-mechani-
handle fragile objects, and be robust in collisions. The combination of cal feedback loop. The system uniquely couples chemo-mechanical
elastically deformable substrates with soft actuators and sensors will allow energy transduction with the re-configuration of the attached reactive
a robot to be folded or compressed and placed into a volume much species, mechanically switching between chemically distinct media in a
smaller than its deployed size, making transportation easier. During this smoothly concerted action. Based on this platform, recently we developed
talk, I will describe my group’s progress towards soft active materials for a novel artificial phototropic soft material which exhibits unique pho-
actuation, sensing, and stiffness control. I will emphasize our work on to-thermo-mechanical behaviors. phototropism is the ability of living plants
flexible, stretchable sensors embedded with liquid metals and manufactur- to track the sun across the sky, to naturally optimize the leaf or flower
ability of liquid metal-elastomer composites. Finally, I will show several orientation with respect to the incident sunlight. Such superior adaptive
prototype soft-bodied systems that incorporate these sensors and light tracking arises from photo-mechanical responsive behaviors of the
variable stiffness actuators to achieve distributed intelligence and plant stems, which mechanically bend toward sunlight dictated by the
functionality. contained photoreceptors. If such biological feature can be realized in
manmade materials it would provide unprecedented capability of adaptive
light tracking, maximizing photon harvesting, and optical beam directing.
Such passive phototropic systems are more energy efficient but remain
Biography
challenging to create, as they do not use external power but the solar
Rebecca Kramer is an Assistant Professor of Mechanical Engineering at
energy or the heat from the solar radiation. To innovate a passively
Purdue University. She holds the degrees of B.S. from Johns Hopkins
phototropic system, we have developed a photo-thermal-responsive
University, M.S. from the University of California at Berkeley, and Ph.D.
material, which couples the thermos-responsiveness of smart hydrogel
from Harvard University. At Purdue, she founded The Faboratory, which
and the photo-responsiveness of nanomaterials. Upon irradiation the
contains a leading facility for the rapid design, fabrication, and analysis of
volume of the soft material can shrink to ~50% of its original size. When
materially soft and multifunctional systems. Her research expertise is in
illuminated by a light beam from an arbitrary incident angle, the high-as-
stretchable electronics, responsive material actuators, soft material
pect-ratio stem-like pillar made of the homogeneous materials precisely
manufacturing, and soft-bodied control. Dr. Kramer currently serves as an
bent towards the light with high alignment rate of up to 98%. The mecha-
Associate Editor and Editorial Board member of Frontiers in Robotics and
nism has been investigated by computer simulation of the photothermal
AI: Soft Robotics. She has delivered over 40 international presentations
and mechanical behaviors. It has been found the well-controlled local
including an interactive presentation at NASA’s Technology Day on Capitol
heating cause temperature gradient and the instant asymmetric shrinkage
Hill. She has authored over 30 technical publications in journals, proceed-
of the responsive material along the light path provides the unique
ings and books, and currently holds three US patents. She is the recipient
bending angle self-correcting mechanism. The rapid and precise incident
of the NSF CAREER Award, the NASA Early Career Faculty Award, the
light tracking of our system brings a wealth of interesting dynamic control
AFOSR Young Investigator Award, and was named to the 2015 Forbes 30
mechanics fundamental questions to further explore and has shown the
under 30 list.
promise in wide applications in optics and optoelectronics devices such
as solar cells, waveguide, and photonics.

Biography
Ximin He is an assistant professor of Materials Science and Engineering
and the Biodesign Institute at Arizona State University since 2014. Dr. He
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was postdoctoral research fellow in Wyss Institute of Bioinspired Engineer-
ing and School of Engineering and Applied Science with Professor Joanna