Actively variable transmission for robotic knee prostheses

Abstract

We present a novel powered knee prosthesis with an active variable transmission (AVT) that adapts motor torque and speed output based on the requirements of different ambulation activities. The AVT works in combination with a spring/damper system to allow for both active and passive operation modes. Preliminary tests performed by an able-bodied subject wearing a bypass orthosis show that the proposed knee can support walking on level ground in passive mode, as well as ambulating on stairs with a reciprocal gait pattern in active mode.