Kinematic Performance of a Customizable Single Degree-of-Freedom Gait Trainer for Cost-Effective Therapy Aimed at Neuromuscular Impairments

A majority of robotic gait trainers to facilitate physical therapy for gait rehabilitation in humans are based on multidegree-of-freedom exoskeleton-based systems with sophisticated electro-mechanical hardware and software, and consequently remain inaccessible to vast sections of the populations around the world. This study seeks to advance the development of a single degree-of-freedom (DOF) gait trainer for gait therapy for individuals with neuromuscular impairments. The goal is to offer a cost-effective, accessible solution to cater to the global need for gait rehabilitation. We build upon the previous gait trainer design based on Jansen mechanism and provide an in-depth analysis and experimental validation of its kinematic performance. The device's performance is also tested and successfully demonstrated through trials involving two healthy individuals to examine its kinematic behavior under human-induced load conditions. The gait trainer demonstrates satisfactory performance under both no load conditions and a 2 kg load, exhibiting an area difference of 1% and 7%, respectively. However, when subjected to a 5 kg loading condition, a significant area difference of 27% is observed, primarily attributed to the cantilever loading at the driving shaft. A method to adjust link lengths based on specific human gait trajectories is proposed and validated. Additionally, a cost-effective tool for ankle trajectory measurement is introduced to establish a ground truth. The study demonstrates the potential of an affordable, single DOF gait trainer in facilitating high-volume therapy for those with walking disorders. This research represents a step toward making gait therapy more accessible worldwide.