Design Of A Muscle-Powered Walking Exoskeleton For People With Spinal Cord Injury

Abstract

Many people with spinal cord injury (SCI) use a wheelchair for mobility. This leads to prolonged periods of sitting, and over time can cause their muscles to atrophy. While there are several commercial exoskeletons for walking, there remains a need for a solution that allows a user with SCI to stand and walk under the power of their own muscles. Our group is developing a device that combines a single channel of electrical stimulation with a lightweight, passive energy storing exoskeleton to provide short-range walking for a user with SCI. The muscle energy is stored in a gas spring during knee extension and is transferred to the hip and the knee to complete the gait cycle. A control system has been implemented to coordinate the movements of the legs with the stimulation of the quadriceps. The first-generation prototype weighed 17.05 kg, and preliminary testing with a non-impaired person indicated that the walking speed could be around 0.27 m/s when using the device. Preliminary tests indicated that the concept is feasible. The design needs modifications to prevent relative movement between the user’s body and the structure of the exoskeleton so that a stable standing posture can be achieved. Optimizing the device for weight could potentially lead to a system that is significantly lighter than commercial motor-powered exoskeletons.