Gregory S. Sawicki, Ph.D.
T. Richard Nichols, Ph.D. (Georgia Institute of Technology)
Lena H. Ting, Ph.D. (Georgia Institute of Technology, Emory University)
Young-Hui Chang, Ph.D. (Georgia Institute of Technology)
Keith E. Gordon, Ph.D. (Northwestern University)
Tuning biomechanical energetics with an exoskeleton to improve stability during walking
Wearable robots such as exoskeletons can be powerful tools for helping an individual accomplish different objectives during locomotion, such as improving economy (“gas mileage”), increasing strength, or enhancing stability. The latter objective remains a major unmet public health challenge – falls during walking account for 68% of injuries in the workplace, and 1 in 4 older adults fall each year. Most falls occur because of a destabilizing exchange of mechanical energy between a person and their environment, such as a trip or slip. In terrestrial vertebrates, distal joints and muscles, such as the ankle and plantarflexors, act as dampers to dissipate energy injected by perturbations such as unexpected drops in terrain height. While the hip joint and associated muscles are considered the “motors” of the lower limb during steady locomotion, the role of proximal joints and muscles in responding to perturbations that demand energy generation is unknown. The first aim of the proposed work is to determine the hip’s response, from joint to muscle levels, in responding to destabilizing mechanical energy demands. Elastic exoskeletons could improve stability by tuning biological structures to better perform their energetic roles. Since elastic hip exoskeletons have demonstrated an ability to increase biological mechanical work output at the hip, for perturbations that demand mechanical energy generation elastic exoskeletons may provide a physiology-based approach to improving stability. Thus, the second aim of the proposed work is to evaluate the influence of an elastic hip exoskeleton on stability following transient mechanical energy demands. Together, the completion of the proposed aims will improve our understanding of the role of proximal joints and muscles in the unstable contexts of daily life and can provide the basis for the development of a new generation of bioinspired stability-enhancing exoskeletons.