Desert creatures inspire ‘SandBot’


This is the pre-publication version which was subsequently revised to appear in Creation 33(2):53.
Photo stock.xchng Desert lizard

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.

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).

Published: 23 June 2009


  1. Berardelli, P., One Giant Leap for Robot-Kind, ScienceNOW Daily News, , 9 February 2009. Return to text.
  2. 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.
  3. 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.