Design and Control of a Powered Transfemoral Prosthesis

Abstract

The paper describes the design and control of a transfemoral prosthesis with powered knee and ankle joints. The initial prototype is a pneumatically actuated powered-tethered device, which is intended to serve as a laboratory test bed for a subsequent self-powered version. The prosthesis design is described, including its kinematic optimization and the design of a three-axis socket load cell that measures the forces and moments of interaction between the socket and prosthesis. A gait controller is proposed based on the use of passive impedance functions that coordinates the motion of the prosthesis with the user during level walking. The control approach is implemented on the prosthesis prototype and experimental results are shown that demonstrate the promise of the active prosthesis and control approach in restoring fully powered level walking to the user.

Effects of Prosthesis Mass on Hip Energetics, Prosthetic Knee Torque, and Prosthetic Knee Stiffness and Damping Parameters Required for Transfemoral Amputees to Walk With Normative Kinematics

“…The second conclusion contrasts the approach that a number of previous studies have taken in designing prosthetic knees [17,18]. However, the conclusion may help explain biomechanical and user-based limitations of knees designed in these studies.…”

“…In particular, they have optimized the components to reproduce the knee torques generated by able-bodied humans during walking [17,18]. However, this design approach has a major limitation.…”

Metabolic effects of using a variable impedance prosthetic knee

“…The work of Sup et al has resulted in a combined knee-ankle powered prosthesis that can approximate the kinematics of nondisabled walking over level ground and up-slope ambulation using onboard sensors to control prosthesis gait [21][22]. Commercially, Össur hf is marketing the Power Knee, a direct-drive, servo-controlled device that uses motion of the soundside leg to determine prosthetic knee position [23][24].…”

Conception, design and development of a low-cost intelligent prosthesis for one-sided transfemoral amputees

“…By utilizing specific programs and sensor information, these prostheses may result in a more natural gait (Aaron et al, 2006;Sup et al, 2008;Herr and Wilkenfeld, 2003;Johansson et al, 2005;Kahle et al, 2008;Kapti and Yucenur, 2006;Laferrier and Gailey, 2010). The main differences in the design of these prostheses are in their damping systems because an adequate damping allows for fast transitions in stride velocity, which increases the autonomy of the amputee.…”