This month’s nominee for the Least
Likely Design for Practical Implementation
award is Thermobot, designed by Takeru
Nemoto and Akio Yamamoto of the
University of Tokyo ( www.u-tokyo.ac.jp).
The device operates purely on the basis of
temperature differential using bimetal
deformation for propulsion. In earlier
studies, the professors noted that thermal
deformation of a bimetal eccentric cylinder
caused it to oscillate incessantly.
Thermobot is based on that
phenomenon, with the top half of the
cylinder removed and the remaining
semicircle split vertically into two swinging
We could find no serious suggestions for practical applications, but we’ll go out on a limb and propose that it
might be used in a frying pan to stir gravy ... if you can figure out a way to steer it ... and if the gravy doesn’t
Operation of Thermobot, turning heat into motion.
Attack of the Killer COTSBots
One of the nastiest creatures in the sea is the crown-of-thorns sea star (COTSS) — a multiple-armed starfish with
tube feet and highly toxic spines that can poke into your skin, break off, and require surgical removal. These guys
range in size from about 10 to 14 inches ( 25 to 35 cm) and can have up to 21 prehensile arms. Their danger to
humans is overshadowed, however, by the damage they are
doing to coral reefs.
The COTSS can extrude its huge stomach out through its
mouth and spread it to an area almost equal to its own
diameter. It then secretes digestive enzymes and sucks out the
liquefied coral. Observers have reported as many as 100,000 of
them per square kilometer, so it’s not surprising that recent
population explosions of COTSS have devastated large reefs;
most commonly in Australia but also in the Indian and Pacific
Oceans. In the past, divers have attempted to control the
population by manually injecting them with poison, but they
can inject only about 120 of them per hour.
To improve the kill rate, a group of researchers at
Australia’s Queensland University of Technology
( www.qut.edu.au) have developed the completely
autonomous COTSBot, designed specifically to “seek out and
murder crown-of-thorns sea stars as mercilessly and efficiently
as possible.” The killer bot is basically a 30 kg yellow torpedo with a maximum speed of over two meters per second
and an endurance of over six hours.
It injects each starfish with a recently developed poison that kills it within 24 hours, causing “discolored and
necrotic skin, ulcerations, loss of body turgor, accumulation of colorless mucus, loss of spines [and] large, open sores
that expose the internal organs.” Yum!
Researchers envision a fleet of the subs that can “murderize” most of the starfish on a reef within days or weeks.
COTSBots are said to pose no threat to humans but — just to be safe — you probably should avoid swim trunks with a
picture of a COTSS on them.
Concept of the COTSBot sea star killer.
8 SERVO 01.2016