Design, Development, and Evaluation of a Bionic Knee-Ankle-Foot Orthosis Retrofit for Walking Gait Normalization

Abstract

A smart bionic leg orthosis (SBLO) was created by engineering an electromechanical retrofit to a conventional, fixed knee-ankle-foot orthosis (KAFO). The SBLO detects the wearer's walking motion and intelligently bends the brace at the proper time during the walking cycle, replicating healthy knee function. Whole-body walking gait data was collected, analyzed, and statistically modeled to evaluate the SBLO and assess control algorithm robustness. Kinetic and kinematic analyses show the SBLO meets critical human leg motion parameters, indicating a partial restoration of limb functionality, and biomechanical simulations suggest the SBLO can reduce patient energy expenditure by more than 30%. Test results from a limb affected by post-polio syndrome show up to 99.84% normalization of eight walking gait characteristics across multiple mobility scenarios when using the SBLO rather than a fixed KAFO, including >75% reductions in gait pathologies. The SBLO is inexpensive yet offers more functionality than state-of-the-art solutions, by providing dynamic motion assistance to aid the wearer during walking.