Development of a prototype powered exoskeleton for spinal cord injury

Abstract

This study describes a powered exoskeleton designed to restore the gait of locomotion in individuals with spinal cord injury, and testing of its operation. The device comprises an adjustable frame to support the patient’s weight, four actuators to motorize the hip and knee joints, and a motion sensor for gait trigger to detect pelvic tilt. It is controlled using a programmable logic controller system. Additionally, it includes crutches with a wireless switch. The length and width of the frame can be adjusted. Moreover, the joint angles for abduction and adduction can be adjusted to fit X- and O-legs. The actuator consists of a reduction gear with a ratio of 1:101 and a brushless DC motor, which generates a maximum torque of 90.9 Nm. A preliminary fitting test for healthy subjects showed that the frame could be adjusted to fit the shape of the human lower limbs, confirming the effectiveness of the adjustment functionalities. The operation test demonstrated that the target motions could be performed normally under unloaded conditions, and then confirmed that a standard-sized healthy male wearing the prototype could safely perform the standing-up, walking, and sitting-down actions. In addition, crutches with wireless switches enabled remote operation, improving usability.