A Power-Capable Knee Prosthesis With Ballistic Swing-Phase

This paper proposes a new approach to the design of a power-capable prosthesis; namely, one that expands the behavioral capability of a knee prosthesis into the powered quadrants of the power plane, without sacrificing the range of capable behaviors in the passive quadrants, relative to existing passive microprocessor-controlled knee prostheses (MPKs). It is well-known that swing-phase knee motion during walking in healthy human gait results from the combination of inertial coupling between the thigh and shank, gravitational effects, and passive behavior at the knee. Motor-actuated prostheses with powered stance and swing capabilities have recently emerged, but none have been shown to provide a strictly-passive biomimetic swing-phase. This paper describes an approach that enables expansion of knee behavior into the powered quadrants of the power plane, without sacrificing the ability to provide a strictly-passive biomimetic swing-phase, or the passive stance-phase behaviors provided by passive MPKs.