Soft robotic gripper uses vacuum pressure and a beanbag to move objects

[Reefa]

Robots are getting faster and stronger all the time, but for the power and cunning engineered behind all those servos and actuators, the subtle elegance of picking up an object is still a tricky thing in robotics. Designing a conventional grasper that pinches together and lifts items is the traditional approach, but it might not be the best. A new type of vacuum-powered gripper called the Versaball is now commercially available.

This device was originally devised a few years ago as part of a collaboration between researchers at Cornell, University of Chicago, and iRobot (with funding from DARPA). The Versaball is able to grab hold of things using a property called jamming transition. The Versaball is a serious piece of robotics gear, but the concept can be illustrated with regular household items.

Small granular materials that are packed into a rubber housing like the one at the end of the Versaball have an almost fluid consistency. If you press the bulbous shape down on something, the material flows around it. Jamming transition is applied when the air is evacuated from the rubber membrane. This causes the granular particles to be pulled closer together and act more like a solid, thus locking the object into place. It’s the same phenomenon you might have experienced with vacuum-packed goods like coffee grounds — they’re hard as a rock until you open the package. In fact, an early version of the Versaball used coffee grounds in a regular balloon.

The Versaball, sold by Empire Robotics, is much more advanced than a party balloon filled with coffee, but the principal is the same as it ever was. The super-durable rubbery bulb is pressed into an object, allowing the granular material to fill in around it and solidify when the air is pulled out (in under 0.5 seconds). The business end of the Versaball has a beanbag-like consistency and comes in three-inch and six-inch varieties. Assuming a solid grip, the Versaball can lift up to 20 pounds.

This approach is appealing because it has what roboticists call high error-tolerance. When dealing with a mechanical grasper, the operator has to very carefully align the device to pick something up. Jamming transition is just more forgiving — the head doesn’t have to be right on the money to attach firmly to something, and the surface doesn’t have to be smooth or regular. For systems relying on robot vision, this is even more desirable.

Empire Robotics sees the Versaball having applications in robots, of course, but also in assisted living, prosthetics, and handling hazardous material. The first batches of Versaball kits are expected to ship later this month.

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