For robots and rehabilitation devices alike, leg control often
relies on matching motion patterns that have been recorded from
human subjects performing the target tasks. While sufficient
for these tasks, such a control approach denies artificial legs
the agility and adaptiveness that human legs display in normal
The understanding of the interaction between legged dynamics and
motor control could trigger more human-like artificial leg
behavior. The strength of the neuromuscular human model
introduced in the section on
motor control is its reflexive control which auto-adapts to
environmental changes by taking advantage of principles underlying
legged system dynamics. Applying this control to artificial
legs that interact with amputees or patients should allow these
persons a greater agility and adaptiveness in locomotion than
current artificial legs provide.
Control of a powered ankle-foot prosthesis that inherits
auto-adaptiveness of neuromuscular model
We found in clinical trials with a transtibial amputee walking on
level ground, ramp ascent and ramp descent, that an adaptation in
prosthetic ankle work occurred in response to the ground slope, in
a manner comparable to intact subjects, without the difficulty of
explicit terrain sensing.
The results demonstrate the potential that applying neuromuscular control strategies has to the control of legs in rehabilitation robotics. But the actuated ankle presents just a first step in that direction. Future prosthetic and orthotic devices, as well as the legs of spinal cord injured patients, will have to be controlled concerting several joints. I am interested in developing such articulated leg controls based on neuromuscular control strategies.
More details about this research can be found in