A Low-Profile Hip Exoskeleton for Pathological Gait Assistance: Design and Pilot Testing

Hip exoskeletons may hold potential to augment walking performance and mobility in individuals with disabilities. The purpose of this study was to design and validate a novel autonomous hip exoskeleton with a user-adaptive control strategy capable of reducing the energy cost of level and incline walking in individuals with and without walking impairment. First, in a small cohort of three unimpaired individuals, we validated the ability of our control strategy to provide hip flexion-extension torque that was proportional to the biological hip moment and reduce the energy cost of level and incline walking (24 +/- 5% and 13 +/- 5% reductions, respectively). Next, in a clinical feasibility experiment with an individual with significant walking impairment from cerebral palsy, we demonstrated that our untethered device and adaptive control scheme improved hip extension by 14 degrees across the gait cycle, reduced average rectus femoris and semitendinosus muscle activity by 23% and 46%, respectively, and resulted in a 15% improvement in metabolic cost relative to walking without wearing the device.