Cockroaches Inspire Robots

Anyone who has tried to traverse a sand dune on foot knows it’s a far more difficult task than walking on asphalt. Even driving across soft-packed sand presents problems because, as ScienceNOW writer correspondent Phil Berardelli explains, “the loose agglomeration of sand grains often collapses into a hole under the weight of a vehicle’s wheels and provides too little traction for those wheels to roll back out.”

Robots are not exempt from the travails of sandy travel, and the mechanical rovers on Mars have encountered the problem as well. But researchers inspired by nature may have the solution. A team led by Georgia Tech physicist Daniel Goldman realized that the limbs of desert animals solve this sandy problem: they do not move across the sand at a steady rate. Instead, each limb moves slowly when in contact with the sand, then rapidly moves through the air until it makes contact with the sand again. Thus, the animals—such as lizards and cockroaches—can move quickly without getting trapped in the sand.

The team constructed the six-limbed SandBot to demonstrate the principle. An axis at its center allows one side (three legs) to move very slowly through sand while the other side (three legs) rotates rapidly forward. Once that side has touched ground, the roles reverse.

In trials, SandBot sped through a sand-like track at a rate of 30 centimeters per second (or about a foot per second), at least 15 times faster than the Mars rovers can move. Of course, the rovers have wheels, which is why the team now wants to created a wheeled version of SandBot.

Yet again, scientists are taking a cue from God by mimicking this design, which seems so obvious once understood to make one wonder, “why didn’t I think of that?”