Robotic tentacles get to grips with tricky objects
posted 2006-05-08 17:33:50 latest updated 2006-05-08 17:40:43
robotics Robotic "tentacles" that can grasp and grapple with a wide variety of objects have been developed by US researchers. Most robots rely on mechanical gripping jaws that have difficulty grabbing large or irregularly shaped objects. Replacing these with tentacle-like manipulators could make robots more nimble and flexible, say the scientists.

The tentacle-like manipulators, known as "Octarms", resemble an octopus's limb or an elephant's trunk. They were developed through a project called OCTOR (sOft robotiC manipulaTORs), which involves several US universities and is funded by the US Defense Advanced Research Projects Agency (DARPA).

"An elephant's trunk can pick up a peanut or a tree trunk," says Ian Walker, a member of the project team from Clemson University in South Carolina. "This ability, inherent in the OCTOR robots, gives OCTOR arms a huge advantage over conventional industrial robots."

Just like a real tentacle, an Octarm simply wraps itself around an object in order to manoeuvre it. This allows it to grasp objects of various sizes and shapes and could let robots deal with unpredictable real-world situations, the researchers say.

Narrow spaces

Each Octarm is powered by compressed air and has surface pressure sensors, positional sensors and a camera mounted at its tip. This allows the limb to nimbly investigate pipes, tunnels and other narrow spaces.

The Octarms developed so far are each around a metre long, although the design could easily be scaled up or down, the researchers say. Only one has been attached to a robot at a time, but the researchers say several could work together in future.

"Coordinated control of multiple arms would be a real challenge," says Chris Rahn, another project member from Pennsylvania State University. But it is by no means impossible, he adds. He believes the robotic tentacles could perhaps one day be used to create a robotic octopus or even a backpack with extra limbs.

Heavy and fragile

Tests involving an Octarm attached to an industrial robot showed that it can just as easily grapple with a heavy box as a small fragile object. Several videos created by the researchers show an Octarm moving irregular objects, lifting fragile ones and even exploring a pipe. The manipulators have even been successfully tested underwater.

It is not clear what military purposes the Octarms will be used for, but the limbs have also been attached to Talon robots, which are typically employed for reconnaissance and bomb disposal tasks.

Like DARPA's robotic "pack mule", BigDog, the robotic tentacles are part of DARPA's Biologically Inspired Multifunctional Dynamic Robots (BIODYNOTICS) programme.

New Scientist, May 2006

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