A compact and cost-effective gait simulator to advance prosthesis development with reduced reliance on human subject...

Area of Science:

• Biomedical Engineering
• Biomechanics
• Prosthetics and Orthotics

Background:

• Gait simulators are vital for prosthetic knee development, but high costs and limited degrees of freedom (DOF) hinder their use.
• Current simulators face a trade-off between sophisticated, expensive systems and those with insufficient DOF for accurate testing.

Purpose of the Study:

• To determine the minimum required DOF for a cost-effective gait simulator for prosthetic knee testing.
• To reduce the dependency on extensive user trials in the prosthesis development cycle.

Main Methods:

• Numerical simulations of prosthetic leg swing phase with varying arrested DOF of the thigh segment.
• Comparison of different DOF configurations against a six-DOF ideal case using 3D gait data.
• Development and hardware-in-loop simulation testing of a compact, modular gait simulator.

Main Results:

• Only sagittal plane movements (flexion-extension, vertical and horizontal translation) are essential for prosthetic knee testing.
• The developed compact gait simulator effectively assessed prosthetic knee performance.
• The IITM polycentric knee (IPK) was found to fully extend before heel contact, indicating a need for redesign of its extension stop.

Conclusions:

• A cost-effective gait simulator with minimal DOF (sagittal plane movements) is feasible for prosthetic knee testing.
• This approach can significantly reduce development costs and the need for user trials.
• The study highlights critical design insights for prosthetic knee performance and safety, such as the IPK's extension stop functionality.