Skip to main content

Who Says Hands Need Five Fingers?

Human fingers are pretty cool: They grip, they pinch, they squeeze. They can crush bugs and hold delicate crystal. They're amazing! Because of all the wonderful things fingers can do, it makes sense that we try to replicate them on our human analogues. But recreating robotic fingers is difficult and can get rather costly. To overcome the challenges that come with creating a robotic hand, one group of scientists ditched human digits altogether and developed something far simpler but just as effective.


Creating robotic replicas of human hands is troublesome. It's difficult to get the tension right to grip an object without crushing it. Computers can be strained when controlling multiple joints with umpteen degrees of motion. Instead of trying to replicate our dexterous little fingers, scientists at the University of Chicago and Cornell University opted for another approach, creating a robotic gripper.

The team developed what they called a "universal jamming gripper" out of a latex party balloon filled with ground coffee and a vacuum pump. To operate the robotic appendage, the slack balloon is placed on an object which it surrounds with the loose coffee grinds. Then, the vacuum pump is turned on, sucking out the air inside the balloon. The fluid-like coffee grinds 'jam' into a rigid solid with a fixed grip around the object. Once the pump is turned off, the grains loosen up again and the object is released.

Several types of granular materials were tried in early grippers including sand, couscous, rice and ground up tires. Sand worked the best, but was ruled out for being too heavy. Coffee grinds which jam nearly as well as sand but weigh far less were ultimately chosen.

The gripper can pick up things that have stumped robotic hands in the past like coins and raw eggs. It does have some limitations, struggling with porous objects like cotton balls and failing to lift more than half its own weight.
Even so, the four-inch diameter gripper that was created in the lab could pick up an eight-pound jug of water and the scientists speculate that a gripper with a four-foot diameter could lift a car.

Though it doesn't much resemble a human hand, the gripper could be developed into a new type of prosthetic limb. Since it has only two modes - on and off - it would be easy for users to operate. It could also be used to clean up debris after a catastrophic event, such as the earthquake in Haiti.

To learn more about this cool little gripper, listen to the podcast from PhysicsCentral below:


Comments

  1. Very cool! The most elegant solution is often the simplest!

    ReplyDelete

Post a Comment

Popular Posts

How 4,000 Physicists Gave a Vegas Casino its Worst Week Ever

What happens when several thousand distinguished physicists, researchers, and students descend on the nation’s gambling capital for a conference? The answer is "a bad week for the casino"—but you'd never guess why.

Ask a Physicist: Phone Flash Sharpie Shock!

Lexie and Xavier, from Orlando, FL want to know:
"What's going on in this video? Our science teacher claims that the pain comes from a small electrical shock, but we believe that this is due to the absorption of light. Please help us resolve this dispute!"

The Science of Ice Cream: Part One

Even though it's been a warm couple of months already, it's officially summer. A delicious, science-filled way to beat the heat? Making homemade ice cream.

Over at Physics@Home there's an easy recipe for homemade ice cream. But what kind of milk should you use to make ice cream? And do you really need to chill the ice cream base before making it? Why do ice cream recipes always call for salt on ice?