听
A vine-like robot can steer itself towards a source of heat without sensors, batteries or motors. The technology could be used to create smart hosepipes that approach a burning building or forest fire and steer themselves towards the flames.
at the University of California, Santa Barbara, and his colleagues have created a device about 2 metres long with dozens of segments. The team鈥檚 robot mimics the way that vines and roots use localised sensing to grow towards a source of moisture.
Advertisement
It is made from two long, thin Mylar plastic bags filled with a refrigerant fluid called Novec 7000, which has a boiling point of 34掳C (93掳F). Every 4.5 centimetres, the bags are sealed to form segments. The robot also has a spine of low-density polyethylene that insulates segments on either side of it from each other.
When segments on one side of the robot are exposed to heat, the liquid inside warms and, once it reaches its boiling point, it begins to evaporate and these segments expand, getting fatter, but shrinking in length. Because of the spine, when a segment exposed to warmth contracts, its equivalent on the other side is protected and retains its length, causing the vine to bend towards the source of the heat.
The researchers say using liquids with different boiling points could adjust the temperature at which the robot begins to steer.
In experiments, the robot was able to find a heat source even if it was initially pointing away from it and could navigate around simple obstacles. The researchers say that eversion 鈥� a process by which a soft robot can uncoil from within itself, like an inside-out sleeve being pushed out by an arm 鈥� enables the vine robot to grow from the front, lengthening and steering towards a heat source automatically.
Xiao says the device could eventually be fitted with a hose to carry water or inert gases to heat sources and put out fires or smouldering patches. The robots could operate in dangerous environments, saving humans from the job, and be deployed in huge numbers because of their low cost. Xiao estimates that they could cost as little as $1 per 3 metres.
鈥淵ou can imagine a forest fire. After a lot of the fire has been put out, there are tons of hotspots around. You could have a whole bunch of these out looking for heat sources and putting them out,鈥� he says. 鈥淚t鈥檚 slow. For these applications it鈥檚 OK if it鈥檚 slow, but obviously we would like it to be faster.鈥�
Reference:
