Transfemoral Quasipassive Prostheses

The quasipassive transfemoral prostheses developed in this lab have onboard computation and control, but require minimal electrical power to operate. These devices provide biomechanial functionality without requiring large batteries and actuators.

User-adaptive control of a magnetorheological prosthetic knee -- A magnetorheological knee prosthesis is presented that automatically adapts knee damping to the gait of the amputee using only local sensing of knee force, torque, and position. To assess the clinical effects of the user-adaptive knee prosthesis, kinematic gait data were collected on four unilateral trans-femoral amputees. Using the user-adaptive knee and a conventional, non-adaptive knee, gait kinematics were evaluated on both affected and unaffected sides. Results were compared to the kinematics of 12 age, weight and height matched normals. We find that the user-adaptive knee successfully controls early stance damping, enabling amputee to undergo biologically-realistic, early stance knee flexion. These results indicate that a user-adaptive control scheme and local mechanical sensing are all that is required for amputees to walk with an increased level of biological realism compared to mechanically passive prosthetic systems.

A clinical comparison of variable-damping and mechanically passive prosthetic knee devices -- Although variable-damping knee prostheses offer some improvements over mechanically passive prostheses to transfemoral amputees, there is insufficient evidence that such prostheses provide advantages at self-selected walking speeds. In this investigation, we address this question by comparing two variable-damping knees, the hydraulic-based Otto Bock C-leg and the magnetorheological-based Ossur Rheo, with the mechanically passive, hydraulic-based Mauch SNS.