Origami Arms Extend The Reach Of Drones (VIDEO)

A robotic arm that is stiff when it needs to be but soft enough to fold up on demand could make drones even more useful.

AsianScientist (Mar. 23, 2018) – Researchers at Seoul National University (SNU) in South Korea have developed an origami-inspired robotic arm that is foldable, self-folding and also highly-rigid. Their results have been published in Science Robotics.

Drones equipped with cameras have given us an easy way to take aerial shots and footage of places inaccessible to camera on the ground. Drones would be even more useful, however, if they also had the ability to manipulate objects around them. However, robotic arms are typically too bulky or heavy for mounting on drones.

Flexible, origami-inspired structures could be a lightweight solution. However, the main limitation with foldable structures is that they are typically too soft and not strong enough to pick up objects.

In the present study, a team of researchers at the SNU Robotics Research Center led by Professor Cho Kyu-Jin have developed a robotic arm that has variable stiffness, starting out soft so that it can be folded into a compact structure but becoming stiff when deployed.

The key idea behind the robotic arm is the origami principle of perpendicular folding, where two perpendicular fold lines constrain each other’s movement. Using this principle, the researchers were able to design a hexagonal structure which weighs less than 30 g but can withstand more than 12 kg of compressive load. The structure can easily be unlocked and folded flat by pulling a single wire.

“This wire-driven actuation has a great advantage in scalability,” the researchers said. “When the wire is unwound, the module is extended by rubber bands installed inside and the lockers are installed by the magnets.”

Using a series of collapsible locking units, the team was able to build a robotic arm that could pick up objects and hold on to a camera. When not in use, the arm folds flat for improved manoeuvring, easy take-off and landing.

“Soft robots have great advantages in their flexible movement, but they have a limitation in that they cannot support high load without deformation. This robotic arm uses the variable stiffness technology which gains merits of both rigid and soft robots. In addition, the arm is made of composite of tough ripstop fabric and specially handled strong PET film for the practical use,” Cho added.

The researchers say that their proposed variable stiffness mechanism can be applied to other types of robots and structures in extreme environments such as polar areas, desert, underwater and space.

The article can be found at: Kim et al. (2018) An Origami-inspired, Self-locking Robotic Arm that can be Folded Flat.

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Source: Seoul National University; Photo: Shutterstock.
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