Implementation and Validation of a Data-Driven Variable Impedance Controller on the Össur Power Knee.

Area of Science:

• Biomedical Engineering
• Rehabilitation Robotics
• Prosthetics

Background:

• Commercial robotic prostheses often fail to replicate the clinical benefits seen in research prototypes.
• Limited adoption of robotic prostheses into clinical practice due to performance gaps.

Purpose of the Study:

• To implement and evaluate a phase-based variable impedance controller on a commercial robotic prosthesis (Össur Power Knee™).
• To assess the clinical benefits of the controller for walking and sit/stand tasks in above-knee prosthesis users.

Main Methods:

• Implementation of a phase-based variable impedance controller on the Össur Power Knee™.
• Preliminary experiments with 4 high-mobility above-knee prosthesis users comparing the controller to their prescribed prostheses.

Main Results:

• Users showed increased leg-loading symmetry and speed during sit/stand tasks, indicating easier movements.
• Improved walking gait, including increased toe clearance and early-stance knee flexion, was observed.
• Positive results suggest controller generalization and potential for clinical benefits with commercial prostheses.

Conclusions:

• The phase-based variable impedance controller can yield significant clinical benefits when implemented on a commercial robotic prosthesis.
• This approach demonstrates potential for enhancing the functionality and adoption of commercially available robotic prosthetic devices.
• Further research can lead to robotic prostheses providing concrete clinical advantages for users.