Regular readers might remember the robotic universal gripper that can pick up a wide variety of objects thanks to an elastic membrane filled with coffee grounds. Earlier this year, the developers revealed they had given their versatile gripper the ability to “shoot” objects some distance, and now a team at MIT has “extended” the technology to create a robotic arm that can twist, flex and grip in a way not dissimilar to an elephant’s trunk.

Just like the universal gripper developed collaboratively by researchers at Cornell University, the University of Chicago and iRobot, the robotic arm developed at MIT also uses “jamming granular media” (more commonly known as coffee grounds) that are loose and flexible until the air is pumped out and the coffee grounds jam together to become rigid.

While the gripper uses this process to deform around an object when the coffee grounds are loose and grip it tightly when air is sucked out of the balloon by a vacuum, the MIT team has essentially stuck a bunch of the grippers together so that they form segments in a robotic arm.

The arm – or “trunkbot” – consists of five jamming segments with separate vacuum valves placed in between them. According to IEEE Spectrum, there are also four control cables at 90-degree intervals around the outside of the arm that pull on it to provide movement. When this is combined with the jamming and unjamming of specific segments, the motion of the arm is altered, allowing it to grip objects like an elephant’s trunk.

The MIT researchers presented a paper entitled, Design and Analysis of a Robust, Low-Cost, Highly Articulated Manipulator Enabled by Jamming of Granular Media, at the 2012 IEEE International Conference on Robotics and Automation last week.

Here’s a video showing the trunkbot in action.

Source: IEEE Spectrum