【作者】 杨建坤；

【导师】 金德闻；

【作者基本信息】 清华大学 ， 机械工程， 2006， 博士

【摘要】 人体平衡策略研究是人体运动分析的重要分支,在康复工程、功能损伤诊断、仿人机械以及体育科学等领域都有重要的实用价值。本文通过试验与理论分析相结合的方法,利用人体表面肌电信号作为研究手段,研究了在行走过程中脚跟触地时刻发生意外滑动时健康受试者和单侧大腿假肢穿戴者所采取的应急反应平衡策略及其在假肢设计中的应用。论文工作主要包括以下几个方面:1.利用所需最大摩擦系数等步态参数,对健康受试者和假肢穿戴者在正常路面上行走时所面临的滑动危险性进行了对比分析,结果表明:1)后者比前者面临更大的滑动危险性;2)步态对称性差以及身体侧摆幅度增大是假肢穿戴者面临更大滑动危险的主要原因;3)假肢穿戴者的健康侧和假肢侧的滑动方向截然不同,这是他们滑倒步态的一个主要特征。2.利用主元分析方法,对下肢及腰腹部位主要肌肉的肌电信号进行了特征提取。利用第一主元——“肌肉功率”,分别对健康受试者和假肢穿戴者在滑倒过程中采取的平衡策略进行了分析,提出了基于“防滑策略”和“防倒策略”的人体两阶段平衡策略的原理,指出滑倒过程中健康受试者将连续采用两个阶段的平衡策略,而假肢穿戴者通常只采用其中一种策略。此外,当滑动分别发生在健康侧或假肢侧时,假肢穿戴者采取的平衡策略是完全不同的。3.基于两阶段平衡策略的原理,建立了反映滑倒特征的二维多刚体人体动力学模型,结合从步态试验中得到的运动学参数和肌电信号,计算分析了健康受试者滑倒过程中的关节力矩,得到了力矩幅值增大、波动明显以及关节阻尼增大的结论。4.从两阶段平衡策略原理的角度出发,探讨了提高单侧大腿假肢穿戴者在湿滑路面上的行走安全性问题,并将平衡策略应用于具有力矩控制功能的新型多杆机构膝关节的设计之中,开发了大腿假肢样机,基本实现了改善步态、降低滑动危险性的预定设计目标。本文的研究工作得到了国家自然科学基金(NO. 30170242)和高技术研究发展计划(“863”)基金(NO. 2001AA320601)的资助。更多还原

【Abstract】 The study on human balance strategy is a major branch of human motion analysis. It is practically important in many fields, such as rehabilitation engineering, functional impairment diagnose, humanoid machine, sport science and so on. Using surface electromyography (sEMG) signals and via the method of combining experiment and theory analysis, the reaction strategy of human balance employed by both healthy persons and unilateral trans-femoral prosthesis (UTFP) users when they encounter an unexpected slip incident at the heel-contact moment during walking is investigated in this dissertation. The work was also extended to the application of the strategies to prosthesis design. The research work finished in this dissertation is divided into the following four aspects:1. Based on the analysis of gait parameters, e.g. the peak value of required coefficient of friction, the slip potential faced by UTFP users when walking on the normal surface, was compared with that of the healthy persons. It is found that 1) the UTFP users face greater slip potential than healthy persons; 2) the main reason for UTFP users to face greater slip potential is that both the unsymmetry of their gait and the body swing in the frontal plane are more serious than that of the control group; 3) the slip direction is entirely different when the slip occurred on the intact side and the prosthetic side, which is a main character in the slip gait of UTFP users.2. Via principal component analysis, feature extraction was performed on the sEMG signals which had been recorded from the muscles on legs and around waist of both healthy persons and UTFP users during slip events. Using the first principal component—“muscle power”, the balance strategies which both healthy persons and UTFP users employed in slips were investigated in details. It is found that there are two steps of balance strategies in the slip events including“anti-slip”and“anti-fall”, which is defined as two-step balance strategy. And the healthy persons can adopt both strategies in time during slips, while usually only one strategy can be performed for UTFP users. Besides, when slips occurr on the prosthetic side or the intact siderespectively, UTFP users would adopt entirely different strategies.3. Based on the principle of two-step balance strategy, the 2-D multi-rigid dynamical mathematical model of human body for slip gait was developed. With the assist of kinematical data and sEMG signals from gait experiments, the joint moments of healthy people were calculated and analyzed. The results indicate that the amplitudes of joint moments, the fluctuation of joint moments and the friction moments on joints increase significantly in slips.4. From the point of view that the amputee and the prosthesis constitute a man-machine system, the ways to improve the safety of UTFP users during walking on slippery condition are discussed preliminarily. Moreover, the principle of two-step balance strategy is applied to the design of new artificial knee joint with moment control function. The specimen prosthesis has achieved the original goal of improving gait performance and reducing the slip potential during the UTFP users walking on normal path.This work was financially supported by the National Natural Science Fund (NO. 30170242) and National Hi-Tech Research and Development (863) Program (NO. 2001AA320601).更多还原