Design Optimization of Series Elastic Actuator (SEA) for Lower Limb Rehabilitation Exoskeleton

Wearable robotic exoskeleton devices have seen extensive development across medical rehabilitation applications. By combining advanced robotics and bio-mechanics, rehab exoskeletons aim to restore mobility and functionality to individuals with mobility impairments caused by spinal cord injuries, stroke-related disabilities, and musculoskeletal disorders. The success of lower limb rehabilitation exoskeletons hinges on seamless force transmission across the man-machine interface. To achieve this, various types of actuators are employed, with series elastic actuators (SEAs) playing a pivotal role. While earlier studies have utilized SEAs in exoskeleton designs, authors rarely provided insights into the rationale guiding their choice of elastic component shapes and sizes. This study bridges the gap by presenting a systematic approach to designing and optimizing the elastic element within SEAs. Focusing primarily on the knee joint, this work employs third-degree and fourth-degree Bezier splines to define the contours of the elastic components. Through optimization and finite element analysis, this research seeks to enhance the compliance and efficacy of lower limb rehabilitation exoskeletons, ultimately contributing to the advancement of assistive technologies for individuals with lower limb dysfunction.