Development of an Active Biomimetic-Controlled Transfemoral Knee Prosthesis

Abstract

Commercial available knee prostheses are still limited because most of them comprise passive elements that store and deliver energy during the gait cycle, but without providing additional energy. This inability to provide additional energy affects the performance of passive prostheses, which in some cases demands up to 60% of additional metabolic energy to perform a gait cycle. Recent research works have focused on the design of active knee prostheses, including the development and implementation of control strategies such as electromyographic (EMG) signals. However, the results of such implementations reveal that these control strategies are still limited because of the relatively long time response and inaccurate movements. This paper presents the design of a new biomimetic-controlled knee prosthesis for transfemoral amputation. The aim is to contribute to the development of simple and effective active knee prostheses. The proposed prosthesis consists of a polycentric mechanism obtained from the body-guidance kinematics synthesis of a four bar linkage. This synthesis is based on the natural movements of the human knee, taking into account the shortening effect of the leg during the walking process to avoid trips. The prosthetic knee mimics the human motion of the healthy leg by means of an echo-control strategy. An experimental prototype has been implemented and tested on a workbench. The experimental results have demonstrated the usability of the proposed biomimetic active knee prosthesis.

Relying on more sense for enhancing lower limb prostheses control: a review

“…Instead of using a monocentric knee prototype, Bernal-Torres et al [11,12] proposed a concept of an active polycentric knee prosthesis using the echo-control schema. An inertial measurement unit fixated on the contralateral thigh estimates the trajectory of the unimpaired knee.…”

“…Typically, kinematic sensors like IMUs or GONIOs are used. Using contralateral leg information seems to be a common concept [10][11][12][13]. However, simple echo-control strategies caused errors, especially at the beginning and the end of an activity, when the limbs are not required to "echo" each other.…”

Design and Control of a New Biomimetic Transfemoral Knee Prosthesis Using an Echo-Control Scheme

“…It is believed that the development of such prostheses would enhance the rehabilitation process and daily living performance of amputees. To overcome these limitations, the authors have proposed a new concept based on the combination of a polycentric knee prosthesis and an echo-control strategy [ 35 ].…”