Lower Limb Exoskeleton With Energy-Storing Mechanism for Spinal Cord Injury Rehabilitation

Abstract

Statistics from the National Office for Empowerment of Persons with Disabilities (NEP) indicate that Spinal Cord Injury (SCI) is a major cause of disability in the Thai population. Various rehabilitation methods are available to support SCI patients. Assistive robots, such as exoskeletons and prosthetics, are very useful for improving quality of life. Robotic exoskeletons have evolved as rehabilitation methods that can overcome some of the current health-related effects of SCI. In the current study, a lower-limb exoskeleton was developed to assist or rehabilitate a physically challenged person who has lost mobility owing to SCI. To overcome energy storage issues related to existing designs, the device uses a spring and camshaft system that is integrated with the robot structure to reduce the required energy by absorbing the body weight into spring potential energy and released by the cam design. Hence, the spring cam system significantly reduced torque on the joints, with approximately $17-30\%$ reduction in the angle joint and $40-48\%$ reduction in the knee joint. Control of the exoskeleton is carried out by analyzing brain signals (EEG) and eye movement signals (EOG), which are combined with the control system to perform daily activities, such as walking, turning, and standing. This exoskeleton boasts a maximum walking speed of 0.5 m/s and a remarkable two-hour full-load operation, making it a promising solution for enhancing the mobility and quality of life of individuals with SCI. The effectiveness of the developed exoskeleton in assisting individuals with mobility impairments was validated through comprehensive laboratory-level experimental analysis.

Keywords

• Spinal cord injury (SCI)
• robotic rehabilitation
• lower limb exoskeleton
• medical robotics
• brain-computer interface
• gait analysis