Development and control of a lower extremity assistive device (LEAD) for gait rehabilitation

This research developed a wearable lower extremity assistive device intended to aid stroke patient during rehabilitation. The device specifically aims to assist the patient in sit-to-stand, stand-to-sit, and level-walking tasks in order to promote active gait rehabilitation exercises. The device adopts an anthropomorphic structure with hip and knee joint actuated in sagittal plane. A finite state machine strategy was proposed to control the device. At different states, appropriate assist torque is added to each joint. EMG signals are used to assess the assist performance. Tests on an able-bodied subject show that the device could successfully detect and transit between states. In sit-to-stand tasks, the integrated EMG (iEMG) of the Vastus Medialis for standing up with 11 Nm of assistance torque were found to be significantly less (P = 0.00187) than the iEMG of without assistance for standing up which indicate reduced muscle effort with the device assistance. Results show the device could potentially assist stroke patient in similar tasks.