When we think of robots, for most of us what springs to mind is a ‘mechanical creation’ made from metal and plastic. But there is an alternative which seeks to better mimic biological systems, and that’s the soft robot.
Soft robots are made from materials such as silicone, which is what scientists at Harvard University have used to mould their particular version of the soft robot. But far from looking like R2-D2 out of Star Wars or a ‘Transformer’, their robot looks like a white, floppy three-legged jellyfish.
It also has one other interesting characteristic - it’s a robot that jumps.
This isn’t the first time that robots have been able to leap upwards. Previously this has been done using pneumatic systems with tubes being used to control the robot’s actuating systems with appropriately timed ‘puffs of air’.
The Harvard soft robot, on the other hand, uses tubes that feed precise quantities of a mixture of methane and oxygen into the robot’s legs.
A spark from high-voltage wires that are embedded within the robot’s legs then ignites this gaseous combination, causing an explosion. It’s the expansion of the gases that generates the jump.
Using this approach, researchers have been able to produce leaps of over 30 cm, at speeds of four metres per second. This is faster than was previously possible with ‘pneumatic jumpers’.
While using explosions for propulsion does put stress on the soft robot, their duration is minimal. This means that the energies created can be absorbed by the soft robot, with its temperature rising on average by less than one Kelvin as a result. This and the ability of the silicone itself to twist and flex helps the robot remain remarkably resilient to the blasts it is subjected to.
This robustness is to be welcomed, as researchers believe that soft robots could be used in a wide range of applications, not just industrial, but also in search and rescue operations. That however is some way down the line, as considerable technical challenges will need to be overcome.
First, the current robot is tethered by its tubes and wires, and for many industrial robots of the future that may always be the case. However, if later generations of soft robots are to be able to avoid and negotiate obstacles and withstand the hostile conditions they will encounter on rescue missions, they will need to be freed from such constraints. That will mean creating some form of internal combustion engine, and that in turn will require some way to store the energy that’s needed to power it.
Before then there is the more practical challenge of finding ways to control a sequence of explosions so precise that robots can be created to walk and even run, and do so at speed. The prospect of a robot, no matter how soft, out of control and careering around, is not a happy one.
However, this jumping jellyfish represents a significant step towards a very interesting robotic future.
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