The Optimized Mechanical Structure Design of the Exoskeleton’s Lower Limb Knee Joint Based on Sitting Posture Knee Rehabilitation

College of Mechanical and Automotive Engineering, Ningbo University of Technology, Ningbo, China

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Abstract

This study aims to develop an exoskeleton device optimized for seated knee joint rehabilitation, designed in a modular manner, and it is divided into four key components: motion sensors, motor-worm gear units, thigh/shank fixation modules, and connecting pins. SolidWorks is utilized to construct a 3D model for verifying structural rationality, integrating worm gear transmission dynamics analysis, kinematic simulation, structural strength testing, and multi-condition adaptability research. The device incorporates self-centering mechanical structures, adaptive admittance control, and elastic joint stabilization technology. Moreover, the adaptive admittance control algorithm can dynamically adjust output torque based on real-time sensor feedback. Results indicate that the exoskeleton can be assembled and disassembled within 5 minutes, achieving a 60% volume reduction after disassembly. With a motion range of 0°~120° matching human physiological trajectories and a 40: 1 transmission ratio meeting driving force requirements, it is adaptable to patients with heights ranging from 150~185cm and at different rehabilitation stages, enabling precise flexion-extension training and safety protection.