How a humble 1mm worm inspired robotics that could one day be used for search and rescue...
No eyes, no legs and no skin, yet this worm bot could one day be helping out the victims of natural disasters.
The supersized worm bot has been built by University of Leeds engineering fellow Dr Jordan Boyle, to show how biology can inform the development of robotics.
Boyle designed the robot after his PhD research into how the nervous system of the C elegans nematode worm works to propel the 1mm-long creature along.
Boyle's research developed to the point where he decided to design and build a robot that could replicate the locomotion of a real-life worm on a much larger scale after securing funding from the Engineering and Physical Sciences Research Council.
"I found the simple model was able to explain the whole range of locomotion behaviours you see from the worm and it was quite near the end of my PhD that I thought maybe this could actually be useful in a robotics context," he told silicon.com.
The real nematode worm has no skeleton but its robot equivalent has a rigid backbone - much like a snake's - with a series of springs that provide flexibility along the body.
While other snake robots use a central pattern generator to produce a normal motor behaviour - or ideal wave - which a separate control system alters in response to information gathered by sensors, Boyle determined that the nematode worm robot should operate in a different way.
Rather than have a separate control system to calculate how the worm bot should adapt its movements when it meets an obstacle, as snake bots typically do, the worm's locomotion system works in such a way that it's able to adapt to objects in its path as it goes along.
"We completely get rid of pattern generator circuit and instead rely entirely on the sensory feedback, so it's kind of like a reflexive mechanism," Boyle said.
"The key difference is nowhere in the control system is the idealised wave expressed directly. Instead of saying, 'I want the robot to have an S shape with a wavelength of this and an amplitude of that', the nature of the control system [means] as soon as some sort of external force interferes with the idealised wave, the controller doesn't need to actively plan around it - it just tweaks the shape a little bit. But the basic principle of bending from side to side and propagating the wave from head to tail continues regardless," he added.
In simple terms, Boyle designed the robot to respond to its own shape and position rather than react to the obstacles around it. Twelve sensors located along the robot's body - which replicate the stretch receptors on the neurons of the real worm - work out the average angles of three sensors in front and three behind and adjust accordingly.
When a sensor receives the averaged data it then works out how to move in conjunction with the sections in front of and behind it to move it around objects.
No one part of the robot knows its precise shape and this actually helps maintain forward progress. "The brain only has a very rough guess as to its shape but it seems it doesn't need to know its exact shape and it makes it much harder for it to get stuck," Boyle said.
Among future adaptations mooted for the worm bot are a skin, enabling it to move through water, snow or mud, and the intelligence to allow it to react to stimuli in its environment, such as light and sound.
Aside from being a fascinating robotics project, the worm bot could one day have practical real-world uses.
According to Leeds University, the technology could potentially be put to work in scenarios such as searching for survivors in collapsed buildings or delivering aid to trapped individuals in natural disaster zones by navigating irregular gaps and holes in damaged buildings. On a far smaller scale, the worm bot could also be used to access parts of the human body for medical treatment.