Ask a typical robot to pick up a delicate object and it is likely to crush the thing between its clumsy metal mitts. That is why George Whitesides and colleagues at Harvard University have been developing a series of "soft" robots with a lighter touch. Their latest creation is a robotic tentacle that can twist around a flower without damaging it.
The tentacle is made from flexible plastic containing three air channels that run along the entire limb. Selectively pumping air into these channels causes the tentacle to bend, allowing it to curl around objects with a light grip. Splitting the air channels into multiple sections lets separate parts of the tentacle bend in different directions, producing a full 3D range of movement - previous robotic tentacles have been limited to curling in just one direction.
Whitesides's team also experimented with adding a video camera, syringe or suction cup to the end of the tentacle, making it more useful than a simple grabbing arm. The cheap and soft technology behind the tentacle make it ideal for working with fragile objects or manoeuvring in confined and hazardous spaces. The need for air channels makes it difficult to scale the tentacles down, though, limiting them to robots that are at least a few centimetres in size.