Optimization of an unpowered energy-stored exoskeleton for patients with spinal cord injury.

The paper describes a novel unpowered energy-stored exoskeleton (ES-EXO) for spinal cord injured patients in consideration of patients' characteristics and injured levels. It proposed a method to optimize the energy-stored element to decrease the hip joint moment in walking. EMG patterns, ground reaction force and motion data from one participant with complete spinal cord injury at T10 were recorded. A combined human-ES-EXO model was built and the stored-energy element including locations and stiffness of springs were optimized in AnyBody Modeling System. Significant correlations between experimental and simulated muscle activations in without springs condition proved that the model was feasible. With optimized energy-stored elements, the hip flexion moment decreased by 37.2%, activations in abdominal muscles decreased and low back muscles slightly increased. The results suggest that ES-EXO could provide specific walking assistance for SCI patients through adjusting energy-stored elements according to patients' characteristics.