Development of a cost-effective terrain-adaptive prosthetic ankle

Abstract

Prosthetic ankles with the capacity of adapting to terrain and walking speed are found commercially, but are too expensive for the majority of South Africans to afford. This dissertation covers the development of a terrain-adaptive prosthetic ankle to improve accessibility to users and promote user safety. To achieve this, commercially available mechanical components were used to create a DC motor actuated linkage mechanism that interacts with the terrain using carbon foot blades, allowing for real-time terrain adaptation. Additional focus was placed on increasing the minimum toe clearance and stance phase stability to reduce the risk of falling and thereby prioritising user safety.

The system was tested on a test bench that was designed to emulate human walking biomechanics. It was found that the toe clearance was improved at the beginning of the swing phase by 6 mm, which corresponds to a more natural knee motion when compared to a commercial ESAR prosthetic foot at a level incline and 0.5 m/s walking speed. This demonstrates the system’s potential for improving user mobility and safety in comparison to ESAR prosthetic feet. The system achieved significant cost reductions by utilising commercially available mechanical components, while maintaining comparable performance to state-of-the-art systems. Future work will focus on testing the prosthetic ankle on a real amputee, evaluating the durability and terrain adaptiveness of the system in different environments