【作者】 杨丹丹；

【导师】 侯文生；

【作者基本信息】 重庆大学 ， 生物医学工程， 2010， 硕士

【摘要】 人手是最神秘、最复杂的生物运动系统之一,其复杂的生理机能和神经结构是认识神经肌肉系统调控多指协同动作和力量共同执行一系列的行为任务机理的一个巨大的挑战。人手的力量动作依赖前臂肌肉的收缩完成,因此sEMG信号可用于评价手指的生物力学特性。本课题以表面肌电为技术手段研究神经肌肉系统对人手的运动控制策略在康复医学、人体工效学、运动医学、神经生理学和运动机能学领域有重要的学术和应用意义。由于传统的两电极记录结构不能检测单个运动单位水平的活动,高密度sEMG信号在基础研究和诊断医学中具有重要价值,但却没得以广泛应用。而限制其应用的部分原因在于sEMG电极系统的加工技术。针对以上问题,本文首先基于柔性电路板加工工艺设计了一种具有较高柔韧性的线性、栅格电极阵列装置。采用的电极载体材料聚酰亚胺(厚50μm)具有较高的机械柔性和易裁切性,表面镀金(厚度2μm)的电极具有较低的阻抗,特制的聚酯双面胶带用于可重复使用的电极阵列装置的固定。电学性能测试表明该电极系统具有较低的阻抗和良好的重复性;稳定的基线、良好的sEMG信号、较低的噪声水平保证了此低成本电极系统的实际可用性。本文采用JHBM型号的电阻应变式压力传感器将指力信息转换成微伏级的电压信号,然后由仪表放大器AD620和运算放大器OP07构成的两级放大电路转换成毫伏级信号,最后经NI公司USB 6008数据采集卡实现指力数据采集。本文利用以上设计的实验装置对多指肌调控手指运动功能的机理进行了初步的探索研究。设计了食指(I)、中指(M)、食指中指(IM)组合三种手指活动模式,其中,单指输出力量由6N、8N、10N、12N四个力量水平组成,组合模式的由8N、12N、16N组成。在任务手指匹配目标力量的过程中,6通道指浅屈肌的sEMG信号利用两维电极阵列被同步采集。根据有效的力量输出段提取相应通道的sEMG信号,对提取的肌电信号进行20-500Hz的带通滤波,然后计算各通道sEMG信号的RMS,Ptotal,Pmax,并构建了Ptotal和Pmax彩色地形图用于指浅屈肌空间激活特性的研究。通过分析,得到以下三点结果:①指浅屈肌激活区域和激活强度随手指输出力量的增加而增加,从8N到12N增加的过程中最高的RMS的位置向桡侧转移;②不同电极位置处RMS对力量变化的灵敏度存在差异;③在相同的力量水平下,FDS的激活模式显著地受手指活动模式的影响,FDS的激活强度和区域要显著的高于本文设计的其他两种手指活动模式。这些初步的实验结果表明,sEMG信号特征值的特性取决于手指力量输出的水平,电极位置和手指活动模式。目前的工作提示手指力量输出水平和手指活动模式影响指浅屈肌运动单位的空间-时域募集特性;sEMG的特征参数,如RMS,Ptotal及Pmax,可用于反映肌肉活动水平,估计手指的活动模式及肌肉的空间激活特性。更多还原

【Abstract】 The hand is one of the most fascinating and sophisticated biological motor systems,and its complex biomechanical and neural architecture of hand poses challenging questions for understanding the control strategies that underlie the coordination of finger movements and forces required for a wide variety of behavioral tasks. Movements and forces of human hand depend on muscle contractions, thus surface electromyography (sEMG) can be utilized to evaluate fingers’biomechanical characteristics. This paper which study the control strategies of neuromuscular system to finger movement is of great importance in the field of rehabilitation medicine, ergonomics, sport medicine, neurophysiology and kinesiology.Because of the inability of the traditional (2 electrode) recording configuration to detect activity at the level of single motor units, and the value of high-density sEMG has been proven in fundamental research and specific diagnostic questions. However, its applications are no broad partly due to limitations of construction principles of conventional electrode array systems. On this basis then, we developed a type of thin, highly flexible, linear and 2-D multi-electrode sEMG grid device, which is manufactured using flexprint techniques. The material (Polyimide, 50μm thick) used as electrode carrier allows this new sensor to own higher mechanical flexibility;electrodes with gold-coated (2μm thick) surface have a lower resistance;And adhesive electrode array is attached to the skin using specially prepared double sided adhesive tape whose was made of acrylic polymer. Test of electrical characteristic shows this electrode device has lower impedance and well repeatability; high baseline stablility, best sEMG signals and a low signal noise level guarantee its practical application.Strain gauges modelled JHBM convert fingertip force signals into microvolt-level voltage signals, these voltage signals were amplified by means of the two-stage amplifiers which consist of instrumentation amplifier AD620 and operational amplifier OP07, and then complete analog-digital conversion of the fingertip force information using a data acquisition card USB6008 of NI company.This paper conduct the preliminary exploration for control mechanism that multi-digit muscle regulate finger’s motor function utilizing designed devices. The experimental task consist of the four force levels (6N, 8N, 10N, 12N) of separate index finger (I) and middle finger (M), as well as the three force levels (8N, 12N, 16N) of the combination of index finger and middle finger (IM). Five healthy volunteers were required to produce a certain force to match the target force for 5s, and 6-channel sEMG was recorded using a two-deminsion electrode array over FDS simultaneously. sEMG of each channel was extracted based on the effective force segment, and these sEMG were band-pass filtered with frequency range of 20-500Hz respectively, then RMS, Ptotal and Pmax of sEMG for each channel was calculated and colorful topographical maps were constructed for the study of spatial activity. Our experimental results reveal three findings: (1) the spatial distribution region and activation intensity increase with the finger’s force production, and the position of highest RMS was shifted towards radial while finger’s force production changed; (2) the sensitivity of sEMG, defined as the slope of RMS v.s. force strength, differed from the electrode locations; (3) the activation patterns of FDS are markedly affected by the finger’s active patterns under the same force level,and FDS’s activation intensity and region of index finger is observably larger than other patterns designed in our study. These preliminary experimental results indicate that the characteristic distribution of sEMG depends on the finger’s force production level, electrode location and finger’s active pattern. The current work suggests that spatial-temporal recruitment of FDS’s motor units is affected by force production levels and finger’s active pattern, and sEMG’s characteristic parameters such as RMS,Ptotal as well as Pmax can be used as key parameters to reflect muscle activation level and describe finger’s actions and spatial activity of multi-digit muscles.更多还原