Desert creatures inspire ‘SandBot’
by David Catchpoole
Published: 23 June 2009(GMT+10)
Photo stock.xchng
Traversing loose terrain quickly is not easy—even specialty vehicles such
as dune buggies can sometimes end up hopelessly mired in sand. What happens is that
the loose, soft-packed structure of sand grains collapses under the weight of a
vehicle’s wheels and provide too little traction for the wheels to roll back
out.
Robots, such as NASA’s Mars rovers, face a similar problem. If their limbs
move too fast over loose sand, they can become mired. Going more slowly lessens
that risk, but of course that increases travel times.
Researchers led by Daniel Goldman of the Georgia Institute of Technology in Atlanta,
USA, noticed that when desert creatures such as lizards and cockroaches move across
sand, their limbs do not move at a steady rate. Instead, they tread slowly when
in contact with the sand, but rapidly through the air to touch the sand again.
So Goldman and his colleagues applied the same principle to a six-limbed robot dubbed
“SandBot”.1,2 While three of its feet—i.e. those
in contact with the sandy terrain—move slowly, the other three rotate quickly
through the air to position themselves for the next step.3 SandBot is the smallest (2.3 kg) in a series of
biologically inspired hexapedal robots. These robots incorporate the “pogo
stick-like dynamics” observed in many organisms when running on hard ground.
The researchers are hopeful that deeper analysis will further ‘inform locomotion
biology in understanding how animals appear to move effortlessly across a diversity
of complex substrates.’
SandBot has demonstrated it can traverse loose terrain at a speed of about 30 cm
per second—15 times faster than the Mars rovers.
However, the researchers acknowledge there is substantial room for improvement yet.
While SandBot moved “nimbly and rapidly” on some of the prepared substrates,
its less than stellar performance on other surfaces “points to both the need
for a more sophisticated understanding of the physics of motion within granular
media and the possibility of better robotic design and control paradigms for locomotion
on complex terrains”.2
Note also, its top speed above is only about 1 km per hour (⅔ mph), much slower than lizards zooming
across the hot desert sand.
Engineers being inspired by, and seeking to copy, God’s designs is not new.
We have reported many such examples in recent years. For example,
car makers emulating the boxfish, and computer manufacturers installing
quieter cooling fans
inspired by owl wings, and the other articles linked below. Also note that
NASA engineers have
already had a go at a frogbot with the Martian terrain in mind.
The effort put into making SandBot so far has not only given both engineers and
biologists increased admiration for the capacities of organisms. It has also provided
further insight into just how amazingly complex the design of those creatures really
is. And the researchers are hopeful that deeper analysis will further “inform
locomotion biology in understanding how animals appear to move effortlessly
across a diversity of complex substrates.” (Emphasis added.)
Man’s efforts to engineer robots that can emulate what animals do “effortlessly”
surely speaks volumes about the Master Engineer who engineered them to function
so efficiently in the first place. And this Engineer told Isaiah around 700 BC, “As the heavens are higher than the earth,
so are my ways higher than your ways and my thoughts than your thoughts” (Isaiah 55:9).
Related articles
Further reading
References
- Berardelli, P., One Giant Leap for Robot-Kind, ScienceNOW
Daily News, <sciencenow.sciencemag.org/cgi/content/full/2009/209/2>, 9 February
2009. Return to text.
- Li, C., Umbanhowar, P., Komsuoglu, H., Koditschek, D., and
Goldman, D., Sensitive dependence of the motion of a legged robot on granular media,
Proceedings of the National Academy of Sciences USA 106(9):3029–3034,
3 March 2009. Return to text.
- As the research paper (Ref. 2) described it, “SandBot
moves using an alternating tripod gait in which 2 sets of 3 approximately c-shaped
legs rotate synchronously and π out of phase.” Return to text.
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