一种基于最大Lyapunov指数的平衡站立能力评价方法  

A Standing Balance Evaluation Method Based on Largest Lyapunov Exponent

作　　者：刘琨[1] 王洪瑞[1,2] 肖金壮[2] 赵青[3] 

机构地区：[1]燕山大学电气工程学院,秦皇岛066004 [2]河北大学电子信息工程学院,保定071000 [3]保定市第一中心医院中医骨科,保定071000

出　　处：《生物医学工程学杂志》2015年第6期1212-1216,共5页Journal of Biomedical Engineering

基　　金：国家自然科学基金资助项目(61074175)

摘　　要：为了科学评价人体站立平衡能力,本文基于混沌系统非线性分析理论,提出了一种新的评价方法。该方法利用运动平台对受试者足底施加前后方向正弦式运动刺激,采用三个加速度传感器固定于受试者肩、髋、膝,采集人体平衡调节的动态数据。通过重构系统的相空间,计算得到受试者不同体段动态数据的最大Lyapunov指数(LLE),用LLE的差值平方和(SSDLLE)作为平衡能力的评价指标。最后用该方法计算了20位受试者的平衡指标,并与传统评价方法的结果进行对比,结果表明SSDLLE较为符合受试者的平衡表现,可以在一定程度上用于评测人体的平衡能力。此外,结果还表明人体各个关节的协调能力决定了平衡能力的优劣;各体段的混沌特性的差异与个体的站立平衡能力是存在相关性的。In order to evaluate the ability of human standing balance scientifically, we in this study proposed a new e- valuation method based on the chaos nonlinear analysis theory. In this method, a sinusoidal acceleration stimulus in forward/backward direction was forced under the subjects~ feet, which was supplied by a motion platform. In addi- tion, three acceleration sensors, which were fixed to the shoulder, hip and knee of each subject, were applied to capture the balance adjustment dynamic data. Through reconstructing the system phase space, we calculated the largest Lyapunov exponent （LLE） of the dynamic data of subjects＇ different segments, then used the sum of the squares of the difference between each LLE （SSDLLE） as the balance capabilities evaluation index. Finally, 20 subjects＇ inde- xes were calculated, and compared with evaluation results of existing methods. The results showed that the SSDLLE were more in line with the subjects＇ performance during the experiment, and it could measure the body＇s balance a bility to some extent. Moreover, the results also illustrated that balance level was determined by the coordinate abili ty of various joints, and there might be more balance control strategy in the process of maintaining balance.

关 键 词：站立平衡 最大LYAPUNOV指数 评价指标 混沌 加速度传感器 

分 类 号：R33[医药卫生—人体生理学] TP212[医药卫生—基础医学]