KITAKYUSHU, Japan Robots have transformed production lines, but they have an Achilles' heel -- er, hand, to be more precise. Their inability to grip a variety of objects creates a lot of extra work. Often, robotic hands must be designed to deal with specific parts, and when the parts change, the hands must be swapped with new ones.
Now, a Japanese industrial machinery trading company says it has hit on a solution.
The company, Maeda Kiko, developed a robotic grip filled with something called MRalpha -- a magnetic fluid honed by the Kyushu Institute of Technology. The fluid, which hardens when close to a magnet, is enclosed in two hemispheres of specialty rubber. When these hemispheres make contact with a part, they deform to match its shape. A permanent magnet is then brought near, causing the fluid to solidify. This way, the hand can grip the part with just the right amount of force, preventing damage.
This technology will obviate the need to swap hands or reset a robot's programming each time parts are changed. The company, based in the southwestern city of Shimonoseki, aims to commercialize the hand in the near future.
IRON FIST Magnetic fluids are a mixture of ultrafine iron particles in oil. Proximity to a magnet causes the iron particles to solidify. Still, while this sounds relatively simple, there are some complications.
For starters, using iron makes the device heavy. It also leads to high costs. And the magnet must be powerful enough to create a strong, stable grip.
The Kyushu Institute of Technology sought to tackle these challenges by developing a better fluid. The result was MRalpha, a mixture improved by the addition of nonmagnetic particles to the fluid.
When used in a robotic hand, the quantity of iron is roughly half that of conventional magnetic fluids. This reduces both the weight and the expense.
Researchers say the strength of the grip has roughly doubled, enabling two hemispheres 40cm in diameter to hold up 5kg of weight.
Since the technology ensures that parts will not be damaged even if the hand is not precisely controlled, there is no need to program robots to handle specific objects. This could significantly reduce production downtime.
The new hand "will help boost production efficiency at plants that use robots," Maeda Kiko President Kenichi Kunimoto said.
"It can even grab dirty vegetables or fish without damaging them," he added. "In the future, it thus could play a role in automating primary industry."
