In the future, you may be less likely to ask a friend to lend a hand. That’s because you may have a mechanical one attached to your shoulder. Researchers have developed a roughly meter-long robotic arm for use in the workplace. Previous extra limbs have been complex and heavy, but the new one is more practical in several ways. For one, engineers reduced the number of joints from six to three with the use of a “granular jamming gripper.” Instead of a hand or clasp, the gripper is a balloon filled with styrofoam pellets and coffee grounds that conforms to objects and holds them tight when air is suctioned out. What’s more, the arm itself is made with lightweight carbon fiber and aluminum. And the body support resembles an external rib cage with hard and soft components providing both comfort and the ability to sense the arm’s load through pressure on the torso. Funded by Boeing, the arm was developed in part to help airplane assemblers install overhead bins and do other work above their heads, one of the leading causes of workplace strain and injury. The prototype arm, called Aucto, can support more than 20 kilograms, hold tools, and act as a third leg to free a worker’s arms when kneeling and leaning forward, the researcher reported last week at the Robotics: Science and Systems conference in Cambridge, Massachusetts. Further, once the user positions the arm, it uses force sensors, an algorithm, and motors to keep applying the same pressure to the same spot even as a worker moves around. The entire rig, including body support and battery, weighs 5.5 kilograms, carried mostly on the hips. Add three more arms and you can star in your own comic book as the real-life Doctor Aucto.