BME faculty Dr. Gregory Sawicki’s co-authored paper, “Reducing the energy cost of human walking using an unpowered exoskeleton,” was published online in Nature on April 1, 2015. The published results show that humans can get better gas mileage using an unpowered exoskeleton to modify the structure of their ankles, thereby reducing metabolic energy consumption by 7 percent below walking in normal athletic shoes. The lightweight lower-leg device uses a spring and clutch system working in tandem with calf muscles and the Achilles’ tendon while people walk. It weighs approximately the same as a normal shoe and does not require battery power or other external fuel source. “The unpowered exoskeleton is like a catapult. It has a spring that mimics the action of your Achilles’ tendon, and works in parallel with your calf muscles to reduce the load placed upon them,” said Dr. Gregory Sawicki, an NC State biomedical engineer and locomotion physiologist who co-authored the paper. “The clutch is essential to engage the spring only while the foot is on the ground, allowing it to store and then release elastic energy. Later it automatically disengages to allow free motion while the foot is in the air.”
Dr. Sawicki co-authored the paper with Dr. Bruce Wiggin, a former NC State graduate student, along with Dr. Steven Collins from Carnegie-Melllon University. More information is available from NC State’s press release. Congratulations to the research team for their achievements and recognition!