Simulation of stroke gait impairment correction using cable-driven lower limb rehabilitation exoskeleton (C-LREX)

Cable-driven exoskeletons have recently shown great promise in the rehabilitation of stroke survivors. Numerical modeling/simulation provides a cost- and time-effective approach to fine-tuning design parameters of the exoskeletons, hence reducing the need for expensive and time-consuming experimental trials. This study investigated using a cable-driven lower limb rehabilitation exoskeleton (C-LREX) to correct stroke-impaired gait and track reference healthy trajectories. The impact of different levels of impairment and subject anthropometry variation on the model's performance was studied. The C-LREX model was successful in assisting the impaired limb to track the reference trajectory in all impaired gait patterns, except for higher impairment levels (>20° range of motion deviation at the hip joint). Subject anthropometry variation did not affect trajectory tracking when the cable routing was scaled to fit the user's anthropometry. This study confirmed that the C-LREX model could simulate various impaired lower limb gait patterns in the sagittal plane and determine the cable tension requirements needed to correct the impairment. Future work includes expanding the framework to incorporate frontal plane motion and to validate C-LREX performance in assisting biplanar impaired motion.