Beanbag-like robotic hand may simplify gripping
When researchers need a robot to perform gripping tasks, they generally rely on the human-like, multifingered hand. But this approach is computationally complex, requiring controllable joints, force sensors, and visual feedback systems. To design a simpler universal gripper, Eric Brown et al. (pp. 18809–18814) replaced individual fingers with a rubber bag filled with small particles that molds around objects and then contracts and hardens when a weak vacuum is applied. The design eliminates the need for active control systems and allows the device to seamlessly switch between dissimilar objects, such as light bulbs, candies, small metal pieces, or raw eggs. The gripper’s versatility, the authors report, derives from the behavior of the granular material inside the bag, which inherently sits at the threshold between flowing and rigid states, and quickly transitions when the vacuum induces small changes in the bag’s volume. While the concept of a moldable gripper had been previously proposed, researchers did not understand the mechanism of the underlying jamming transition, according to the authors. The authors suggest that the device may outperform robotic fingers when confronted with unfamiliar objects or complex shapes, and that the gripper’s airtight construction should make it useful in volatile environments.
PNAS journal summary for “Universal robotic gripper based on the jamming of granular material,” by Eric Brown et al.
PNAS November 2, 2010 vol. 107 no. 44 18809-18814 doi: 10.1073/pnas.1003250107