  Lower-limb prosthesis wearers are more prone to falling than non-amputees.
Powered prostheses can reduce this instability of passive prostheses. While
shown to be more stable in practice, powered prostheses generally use
model-independent control methods that lack formal guarantees of stability and
rely on heuristic tuning. Recent work overcame one of the limitations of
model-based prosthesis control by developing a class of provably stable
prosthesis controllers that only require the human interaction forces with the
prosthesis, yet these controllers have not been realized with sensing of these
forces in the control loop. Our work realizes the first model-dependent
prosthesis knee controller that uses in-the-loop on-board real-time force
sensing at the interface between the human and prosthesis and at the ground.
The result is an optimization-based control methodology that formally
guarantees stability while enabling human-prosthesis walking on a variety of
terrain types. Experimental results demonstrate this force-based controller
outperforms similar controllers not using force sensors, improving tracking
across 4 terrain types.
