Development and Assessment of Powered and Passive Prostheses to Improve Functionality and Mobility for Individuals with Transtibial Limb Loss

Abstract

One of the major goals for individuals with lower-limb loss is retaining their mobility and independence to stay engaged in community and employment activities. However, mobility-related challenges make physical activity more difficult and fatiguing for this population. The first major contribution of this work is the design and study of an artificial gastrocnemius and its effects on transtibial prosthesis user gait. This thrust saw the development and validation of a prosthesis emulator that couples a powered prosthetic ankle with an artificial gastrocnemius exosuit to restore the mono- and multi-articular functionality of the impaired soleus and gastrocnemius muscles. Transtibial prosthesis users then walked with the prosthesis emulator under a variety of powered ankle and gastrocnemius behaviors. The users’ prosthesis-side hip and knee joint kinetics were analyzed to assess the artificial gastrocnemius’s effects when coupled with different powered ankle behaviors. The second major contribution of this work is the design and study of a bimodal lower limb prosthesis that can switch between walking and running modes. This thrust saw the design of a device that users can quickly reconfigure to suit the locomotive task without the burden of swapping prostheses. Transtibial prosthesis users walked and ran with the bimodal prosthesis prototype and their own walking and running prostheses. Device dynamics and user surveys were analyzed to assess the prototype’s functionality in each task.