ABSTRACT
Flexible variable stiffness actuator is divided into four categories including elastic element, pneumatic element, electric-magnetic element and intelligent material. It is gradually applied in rehabilitation robot. It could adapt the change of patient's impedance in the upper and lower limb rehabilitation robots, ensure the safety of the wearer in the exoskeleton, and improve the biomimetics in the prosthesis. Variable stiffness driving mechanism for rehabilitation robot still has some disadvantages. It is proposed to have compact structure, low power consumption, good stiffness characteristics, high response rate and progressive output torque curve, etc.
ABSTRACT
Objective:To propose a new type of lightweight wearable lower extremity exoskeleton assisted robot system, and explore the feasibility of walking and posture change rehabilitation training for patients with gait disorder and with paraplegia under T4 spinal cord injury (exclusion of lower extremity muscle spasm and obvious pain). Methods:The active and passive hybrid wearable lower extremity exoskeleton assisted robot structure of the hip joint with two-motor active drive and the knee joint passive four-link simulating the instantaneous movement of the human body was designed. Based on modular control, the STM32F767IGT6 and peripheral circuits, attitude acquisition, power supply and crutches module control system were proposed. The exoskeleton robot was worn by a normal person to perform the experiment of leveling, slope and posture transformation and analyze hip/knee /ankle joint angles during exercise, and compare the myoelectric signals of the lateral femoral and medial femoral muscles. Results:The wearer could realize the sitting-standing posture change and the flat/slope walking only based on the exoskeleton robot system, and the hip/knee/ankle angles were basically consistent with the normal walking and the electromyographic signals of the lateral femoral, medial femoral muscle significantly decreased when the robot was worn while walking. Conclusion:The active-passive hybrid lower exoskeleton assisted robot system can still achieve the rehabilitation of walking and posture change while reducing the weight. This verified the feasibility of the assisted robot system with the active dual-motor of the hip joint and the passive four-link structure of the knee joint to help the patients with paraplegia and gait disorder to walk and recover.