Influence of adjustable frictional moments on gait patterns of a prosthetic knee with controllable moment

A dynamic model of a human-prosthesis system for above-knee disabilities is established. Using computer simulation we investigate the effect of the frictional moment on the gait pattern in the swing phase. It is shown that good performance can be obtained when the frictional moment is adjustable over time. The authors have implemented a prototype prosthesis capable of achieving variable damping using an electrorheological (ER) fluid damper controlled by a microprocessor. This device has the ability to actively control the frictional moment thereby greatly improving the function of the prosthesis