A team of researchers from the University of Chicago and Cornell University have developed a new type of robotic arm that can lend an iron hand to humans in need.

The arm, capable of gripping and throwing objects normally challenging for similar robots, uses technology developed at the U of C, which allows an object to be vacuum-packed into a gripping mechanism. Heinrich Jaeger, a U of C physics professor and a researcher on the project, said that this was the first time researchers were able to artificially reproduce the natural phenomenon of “jamming phase transition,” which describes the “transition of material from a malleable to a locked-up, rigid state.”

“This is one of the very first times the concept of a jamming phase transition, developed here at Chicago, has been used to create a thing, an actual machine or an outcome,” Jaeger said.

Although the arm’s shooting capability is not accurate enough for high-precision tasks, the gripper is able to grasp and rapidly project a variety of objects with 85 percent accuracy. The gripper’s ability to pick up fragile and unconventional shapes, Jaeger says, could be applied to emergency situations too dangerous for humans, such as retrieving objects in a fire, and could be used by the military to help develop technology to dismantle roadside bombs.

Jaeger noted that the gripper is different from other more expensive and complex human-inspired robot arms.

“Most grippers out there are using the human hand or animal hand as some sort of ideal inspiration,” he said. “[In contrast,] it is some sort of blob that conforms to any old shape as opposed to something that has two or three fingers,” he said, referring to the jamming phase transition technology.

The gripper molds to the shape of the target object, which is then grasped tightly by a vacuum using negative pressure. To release the object, the gripper uses positive pressure, reversing its tight hold and allowing the object to be shot forward. Researchers call this a “simple universal passive gripper.”

Jaeger emphasized the gripper’s adaptability over its speed.

“You can make a gripper that picks up a soda can really well, but if you have to switch from soda cans to raw eggs, you need something that maybe optimizes not speed but versatility,” he said.

Jaeger was joined by U of C colleagues Eric Brown, a postdoctoral fellow, and researcher Nicholas Rodenberg. Moving forward, Jaeger said that the team would seek to optimize the accuracy and performance of the arm’s jamming force.