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Agonist-antagonist active knee prosthesis: A preliminary study in level-ground walking

Ernesto C. Martinez-Villalpando, SM; Hugh Herr, PhD

Figure. Prosthesis design.

In contrast to traditional purely dissipative prosthetic knees, we propose a biomimetic variable-impedance knee prosthesis with two series-elastic actuators arranged in parallel in an agonist-antagonist architecture. The prosthesis mimics human knee mechanics during level-ground walking, even though the motors of the prosthesis never perform positive work throughout the gait cycle. Because of the variable-impedance nature of the prosthesis, electrical power requirements for walking are modest, allowing for an energetically economical powered knee system. The objective of this adaptive powered knee prosthesis is to improve gait and metabolic energy consumption of transtibial amputees on various terrain conditions.


Volume 46 Number 3, 2009
   Pages 361 — 374


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