Design and Optimisation of a Passive Polycentric Knee Mechanism for Incline Walking

Abstract

The study introduces the design and analysis of a passive mechanical knee prosthesis aimed at improving stability and functional mobility for lower limb amputees. The proposed system includes a dual four bar linkage system that can replicate the natural flexion and extension of the human knee to facilitate both level and incline walking. The mechanism generates a moving instantaneous centre of rotation, posterior to the ground reaction force during the stance phase to produce a stabilizing extension moment, while allowing adequate flexibility during the swing phase. A kinematic model of the knee mechanism was used to analyze the motion characteristics and ensure smooth operation throughout the gait cycle. The fabricated prototype was tested on an able bodied human for both level and incline walking. The experimental results demonstrated the ability of the proposed mechanism in providing stable, controlled motion with a functional range suitable for assistive applications such as prosthetic devices.