An Ankle-Foot Prosthesis for Rock Climbing Augmentation.

Area of Science:

• Biomedical Engineering
• Robotics
• Rehabilitation Technology

Background:

• Transtibial amputation presents challenges for activities requiring complex foot and ankle movements, such as rock climbing.
• Existing passive prostheses offer limited functionality, restricting the biomechanical capabilities of amputees during dynamic activities.
• Enhancing ankle-foot complex function is crucial for improving mobility and performance in individuals with lower limb loss.

Purpose of the Study:

• To design and evaluate a 2-degree-of-freedom (DOF) robotic ankle-foot prosthesis.
• To enable electromyography (EMG) control for volitional movement of the prosthesis.
• To assess the potential of the robotic prosthesis to improve rock climbing ability in individuals with transtibial amputation.

Main Methods:

• Developed a 2-DOF robotic ankle-foot prosthesis with motorized ankle and subtalar joints.
• Integrated EMG surface electrodes for volitional control of prosthesis motion.
• Conducted preliminary evaluations of system parameters (mass, height, velocity, settling time, steady-state error).
• Performed a clinical evaluation with one subject, comparing the robotic prosthesis to a traditional passive prosthesis during rock climbing.

Main Results:

• The robotic prosthesis demonstrated a system mass of 1292g and build height of 250mm.
• Achieved joint velocities of 2.18 rad/s, settling time of 120ms, and steady-state error of 0.008 rad.
• Clinical evaluation showed increased ankle and subtalar range of motion compared to a passive prosthesis.
• Observed decreased maximum knee and hip flexion angles during climbing with the robotic prosthesis.

Conclusions:

• A lightweight, EMG-controlled, 2-DOF robotic ankle-foot prosthesis was successfully designed and evaluated.
• The robotic prosthesis significantly increases ankle and subtalar range of motion.
• The device shows promise for improving biomechanical function and rock climbing performance in individuals with transtibial amputation.