A giant robotic worm has slithered out of a 3D printer in the north of England 鈥� and one day its inventor hopes it could head for earthquake-hit cities in search of people trapped in collapsed buildings.
Many engineers have tried to make robots that can worm their way into rubble, but few have taken a real worm for a model. Now at the University of Leeds, UK, has done just that: he has closely studied the nematode worm Caenorhabditis elegans and written control software that mimics its unique motion.
The nematode can vary its wiggling frequency fourfold, giving it a wide range of speeds and undulating motions 鈥� and yet it has almost no easily detectable neural centre controlling this motion, Boyle says.
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鈥淚t has an unusually small nervous system, comprising just over 300 neurons. Rather than using a central neural subcircuit as a pattern generator, it seems to generate its undulatory motion using around 100 neurons in a way largely driven by feedback from stretch sensors along its body,鈥� he says.
So he has created a 2-metre-long, 16-centimetre-wide robot that moves similarly 鈥� thanks to sensors that control motion in the same way as the worm鈥檚. The robot has 12 articulated segments, each of which can swing from side to side using a geared motor in its centre.
Robot seeks human
Instead of the nematode鈥檚 stretch sensors, the robot senses the angle each segment describes with respect to its spine and control software uses this information to calculate the robot鈥檚 overall undulation pattern and orientation. Microphones, carbon-dioxide sensors (sensing breath) and infrared cameras on its 鈥渉ead鈥� would allow the robot to wriggle its way to people in trouble, says Boyle.
Instead of constructing the 12 segments from aluminium, the worm-snake robot was made from tough nylon-based plastic in a 鈥� cutting the cost to around 拢2000, against the 拢5000 aluminium would have cost.
Boyle hopes to refine the design further. It certainly needs shrinking down, says Julie Ryan of International Rescue Corps, a UK-based group that rushes experienced rescuers to earthquake zones.
Ryan says they currently push 3-metre-long hoses just 4聽centimetres wide into rubble so that cameras or breath sensors on the end of them can see, or sense, trapped people.
鈥淭his robot invention sounds like it鈥檚 on the big side 鈥� you need something relatively small. Maybe they鈥檒l need to make these in a variety of sizes,鈥� she says.
