Energy-recycling steps eyed for post-surgical recovery, aging in place

Missouri S&T News and Events

A Missouri University of Science and Technology researcher wants to make walking up and down stairs easier through the creation of a device that recycles the energy we use to climb and descend.Yun Seong Song, an assistant professor of mechanical and aerospace engineering at Missouri S&T, built the spring-loaded stairs as a postdoctoral researcher at Georgia Tech. He is lead author of a new research paper in the journal Public Library of Science (PLOS ONE)
“When walking down, the spring in the stairs acts as a cushion and brake,” says Song. “The gentle downward movement alleviates work by the trailing ankle, which is what keeps you balanced and prevents you from falling too fast on normal stairs. When going up, these springs help you by giving back the energy that was stored.”
The initial idea was to use energy-recycling prosthetic shoes to help people going up stairs, says co-author Karen Liu, an associate professor at Georgia Institute of Technology’s School of Interactive Computing. Also contributing to the paper is Lena Ting, a professor of biomedical engineering in the Wallace H. Coulter Department of Biomedical Engineering at Emory University and Georgia Tech.
“Unlike normal walking, where each heel-strike dissipates energy that can be potentially restored, stair ascent is actually very energy-efficient; most energy you put in goes into potential energy to lift you up,” says Liu. “But then I realized that going downstairs is quite wasteful. You dissipate energy to stop yourself from falling, and I thought it would be great if we could store the energy wasted during descent and return it to the user during ascent.”
The spring-loaded stairs compress when someone comes down the stairs, saving energy otherwise dissipated through impact and braking forces at the ankle by 26 percent. When going up, the stairs give people a boost by releasing the stored energy, making it 37 ...

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