An Investigation into a Gear-Based Knee Joint Designed for Lower Limb Prosthesis

Area of Science:

• Biomedical Engineering
• Mechanical Engineering
• Prosthetics Design

Background:

• Mechanical-type above-knee prostheses often lack the natural gait dynamics of biological limbs.
• Improving the performance and adaptability of prosthetic knee joints is crucial for user mobility.

Purpose of the Study:

• To design and assess a novel gear-based knee joint for above-knee prostheses.
• To enable the prosthesis to follow residual limb movements for more natural ambulation.

Main Methods:

• Design and integration of a gear set with bracing and bracket arrangement.
• Conducting motion analysis and finite-element analysis (FEA) on knee joint components.
• Comparing FEA results with existing literature data for validation.

Main Results:

• FEA revealed maximum stress of 29.74 MPa and strain of 2.393e-004 in the gear.
• Maximum displacement of 7.975 mm observed in the knee arrangement stopper.
• A factor of safety of 3.5 indicates no risk of design failure.

Conclusions:

• The gear-based knee joint design is feasible and safe for above-knee prostheses.
• Motion analysis results closely resemble the gait cycle of a healthy biological limb.
• This design offers potential for enhanced prosthetic performance and natural movement.