National Geographic : 2014 Nov
Science EXPLORE Spring Motor Screw Belt COMPUTER MOTOR Floor forces Body forces GRAPHIC: SAMANTHA WELKER. SOURCE: HUGH HERR, MIT Less than a year after losing her left leg below the knee in the April 2013 Boston Marathon bombing, professional ballroom dancer Adrianne Haslet-Davis was performing the rumba again. She was aided by a prototype of a bionic leg designed specifically for dancing by Hugh Herr—a double amputee himself— and his biomechatronics team at the Massachusetts Institute of Technology Media Lab. The biggest advantage of the robotic leg over the conventional prosthetic Haslet-Davis usually dances in is its bendable, motorized ankle. The leg has a dozen sensors that react to changing speed, torque, and position by stiffen- ing or relaxing the ankle joint. Herr, who has also designed bionic prosthetics optimized for walking and running, hopes his research will lead to bionic limbs that are so intelligent that “the world can be continuously changing underneath one’s bionic limb” and it will always respond as needed. “I’m more fearless than I was before,” says Haslet-Davis, who notes that by learning to dance with a prosthetic leg, she’s also gained valuable perspective on her life. “I felt victorious before I even walked out onstage.” — Heidi Schultz Dancing Machine REFLEXIVE CONTROL The bionic leg senses informa- tion from the body and the floor, and the computer calculates the correct mechanical response. BATTERY Integrated inside the prosthetic structure to avoid interfering with dancing. BLUETOOTH TECHNOLOGY Allows the bionic leg to be wirelessly fine-tuned using an Android tablet application. MOTORIZED ANKLE JOINT Simulates the work of ankle muscles during specific, subtle movements of dance.