Universal Robotic Gripper

Coffee, Balloons Help Robotic Arm Grip Items

A team of researchers from Cornell University, the University of Chicago, and iRobot have discovered that a balloon filled with granular matter, like coffee grinds, can grip just about any hard, dry object. According to an explanation provided by the scientists, the "universal gripper" passed the notoriously difficult raw egg-coin test.

Balloon filled with ground coffee makes ideal robotic gripper

Graduate student John Amend, left, and associate professor Hod Lipson with the universal robotic gripper.

The robotic gripper conforms to the shape of the item it is lifting.

University of Chicago physicist Heinrich Jaeger uses a soft gripper to hold up a vial. The gripper consists of a rubber membrane around a granular material that can form around objects, then grab them when a vacuum pump is used to harden the material.

Universal robotic gripper based on the jamming of granular material  

Gripping and holding of objects are key tasks for robotic manipulators. The development of universal grippers able to pick up unfamiliar objects of widely varying shape and surface properties remains, however, challenging. Most current designs are based on the multifingered hand, but this approach introduces hardware and software complexities. These include large numbers of controllable joints, the need for force sensing if objects are to be handled securely without crushing them, and the computational overhead to decide how much stress each finger should apply and where. Here we demonstrate a completely different approach to a universal gripper. Individual fingers are replaced by a single mass of granular material that, when pressed onto a target object, flows around it and conforms to its shape.  [...]

Here is a brief diagram explaining how this method works, directly from the PNAS article.