An international team of Seoul National University and
Harvard researchers looked to water strider insects to develop robots that jump
off water’s surface
(July 31, 2015) The
concept of walking on water might sound supernatural, but in fact it is a quite
natural phenomenon. Many small living creatures leverage water's surface
tension to maneuver themselves around. One of the most complex maneuvers,
jumping on water, is achieved by a species of semi-aquatic insects called water
striders that not only skim along water's surface but also generate enough
upward thrust with their legs to launch themselves airborne from it.
Now, emulating this natural form of water-based locomotion,
an international team of scientists from Seoul National University, Korea
(SNU), Harvard’s Wyss Institute for Biologically Inspired Engineering, and the
Harvard John A. Paulson School of Engineering and Applied Sciences, has
unveiled a novel robotic insect that can jump off of water's surface. In doing
so, they have revealed new insights into the natural mechanics that allow water
striders to jump from rigid ground or fluid water with the same amount of power
and height. The work is reported in the July 31 issue of Science.
"Water's surface needs to be pressed at the right speed
for an adequate amount of time, up to a certain depth, in order to achieve
jumping," said the study's co–senior author Kyu Jin Cho, Associate
Professor in the Department of Mechanical and Aerospace Engineering and
Director of the Biorobotics Laboratory at Seoul National University. "The
water strider is capable of doing all these things flawlessly."
The water strider, whose legs have slightly curved tips, employs a
rotational leg movement to aid it its takeoff from the water’s surface,
discovered co–senior author Ho–Young Kim who is Professor in SNU's Department
of Mechanical and Aerospace Engineering and Director of SNU's Micro Fluid
Mechanics Lab. Kim, a former Wyss Institute Visiting Scholar, worked with the
study’s co–first author Eunjin Yang, a graduate researcher at SNU's Micro Fluid
Mechanics lab, to collect water striders and take extensive videos of their
movements to analyze the mechanics that enable the insects to skim on and jump
off water's surface.