摘要
目的依据人体运动学分析,设计一套模仿人体下肢生理结构和运动特点的外骨骼机械结构,研究外骨骼在步行过程中两个不同时相下的生物力学特性,为外骨骼的设计与优化提供研究基础。方法首先根据下肢步态分析,应用三维建模软件进行外骨骼机械结构的设计,在生成实体模型后利用有限元软件进行装配、网格划分以及单元属性赋值,并建立各个构建之间的面-面接触关系,模拟分析外骨骼的应力分布情况。结果在1 k N载荷下,双腿站立(工况1)的最大应力为91.45 MPa,胫骨竖直(工况2)最大应力为154.55 MPa,分别发生在后背支架和髋部,与设计前的传力机制分析结果一致。结论外骨骼在不同工况下应力分布有明显不同。由于在计算中没有考虑到步行过程中可能产生的冲击等不确定因素,在设计优化外骨骼时需要考虑并乘以一定的安全系数。
Objective To design mechanical structure of exoskeleton which simulates physiological structure and kinematic characteristics of lower limbs according to kinematics analysis of human body, and investigate biome- chanical properties of exoskeleton under two different phases of human gait period, so as to provide references for such exoskeleton design and optimization. Methods Based on clinical gait analysis of lower limbs, the me- chanical structure of exoskeleton was first established by using 3D modeling software. Then the physical model was assembled, meshed and materialized by 3D modeling software, and surface to surface contact relationship between each component was also constructed to simulate and analyze the stress distributions of exoskeleton. Results Under the load of 1 kN, the maximum stress of double stance （calculating condition I） was 91.45 MPa and the maximum stress of vertical tibia （calculating condition II） was 154.55 MPa, occurring at the back support and hip, respectively, and such results were in accordance with the analysis results of force transmission mecha- nism got before design. Conclusions The stress distributions of exoskeleton under different calculating conditions were obviously different. Some uncertain factors such as some shock caused during the walking period, which have not been taken into account in the calculation, should be considered for the design and optimization of exo- skeleton and multiplied by a certain safety coefficient.
出处
《医用生物力学》
EI
CAS
CSCD
北大核心
2014年第6期504-510,共7页
Journal of Medical Biomechanics
基金
国家大学生创新训练计划项目(1500-107-050)
关键词
外骨骼
步态
有限元分析
力学特性
Exoskeleton
Gait
Finite element analysis
Mechanical properties
