Biomechanical Design and Prototyping of a Powered Ankle-Foot Prosthesis.

Area of Science:

• Biomechanical Engineering
• Rehabilitation Technology
• Prosthetics Design

Background:

• Existing powered ankle-foot prostheses exhibit limited range of motion and insufficient push-off power compared to healthy biological limbs.
• These limitations impact gait efficiency and natural movement for individuals using prosthetic devices.

Purpose of the Study:

• To design and develop a novel powered ankle-foot prosthesis with an improved range of motion and adequate push-off power.
• To create a design methodology that integrates kinematic and dynamic modeling for optimized prosthesis performance.

Main Methods:

• Developed a dimensionless kinematic model of the lower limb using experimental gait data from healthy subjects.
• Constructed a multibody inverse dynamic model to calculate forces, torques, and optimize prosthesis component sizing.
• Utilized an iterative design process, refining ankle torque and angle to match physiological parameters.

Main Results:

• The prototype achieved an ankle range of motion of 27.6°, closely approximating the healthy human value of 29°.
• The prosthesis generated a push-off force of 1,000 N, falling short of the target 1,600 N due to component budget constraints.

Conclusions:

• The proposed design methodology effectively guides the development of powered ankle-foot prostheses with near-physiological range of motion.
• Further optimization with higher-performance components is recommended to achieve target push-off power levels.