肌电信号的功率谱分析方法

当用传统的检测方法对肌电信号(EMG)进行处理时,会出现较大的个体差异,针对这一不足,我们对其在频域中作具体的分析,提出了一种新的表面肌电信号特征提取方法--功率谱比值法.并在非特定人的条件下,经过多次实验确定实际所用肌电信号的主要频率范围和功率谱的各项参数,将功率谱比值法应用于前臂肌群的表面EMG特征提取,减小了个体差异,进而实现非特定人的动作模式识别.     

多模式人手动作分类识别方法

为了满足手部运动功能康复器的主动康复训练对多种人手动作模式识别的需求,分析了表面肌电信号采样通道设置布局、训练样本制作、特征提取方式、模式分类器结构参数等因素对手部动作识别的影响,设计了针对前臂的表面肌电信号采集方案,分别基于时域统计量、自回归模型系数、小波包分解系数特征设计了BP神经网络分类器。实验结果表明：对6种单指动作、13种多指动作、20种手部动作的最佳平均识别率分别为98.5%、92.4%、90.9%,计算时间小于190 ms,验证了所提出方法的有效性和实用性。     

Phosphorus content of muscle tissue and muscle function in dairy cows fed a phosphorus-deficient diet during the transition period

Phosphorus (P) deficiency and hypophosphatemia are believed to be associated with muscle function disturbances in dairy cows, particularly around parturition. The objective of this study was to determine the effect of dietary P deprivation during late gestation and early lactation on muscle P homeostasis and muscle function in periparturient dairy cows. Thirty-six multiparous dairy cows in late gestation were randomly assigned either to undergo dietary P depletion or to be offered a diet with adequate P content from 4 wk before to 4 wk after parturition. Phosphorus-deficient rations for dry and lactating cows contained 0.15 and 0.20% P on a dry matter basis, respectively. Blood and muscle tissue for biopsy were obtained and electromyographic examinations were conducted on biceps femoris and intercostal muscles in regular intervals throughout the study. Muscle tissue was analyzed for the total P, adenosine triphosphate, adenosine diphosphate, adenosine monophosphate, creatine phosphate, and tissue water content. Dietary P deprivation resulted in a pronounced and sustained decline of the plasma phosphate concentration, reaching a nadir at calving with mean values below 1.5 mg/dL and remaining below 2.0 mg/dL during the first 4 wk of lactation. Hypophosphatemia was not associated with signs of clinically apparent muscle weakness or disturbed muscle function and was not associated with a decline in the content of any of the studied P-containing compounds in muscle tissue. Accordingly, no association between plasma phosphate concentration and muscle tissue P content was found. Electromyographic examination identified subclinical effects on motor unit action potentials that are indicative of disturbed neuromuscular functionality. Increasing occurrence of pathologic spontaneous activity possibly resulting from membrane instability of nerve or muscle cells and suggestive of myopathy was also recorded as P deprivation progressed. These effects were predominantly observed in intercostal and to a lesser degree biceps femoris muscles. Electromyographic parameters affected by P deprivation were found to be associated primarily with the plasma phosphate and to a lesser extent with the amounts of energy storing P-containing compounds contained in muscle tissue. These results indicate that prolonged and pronounced dietary P deprivation in transition dairy cows leads to marked sustained hypophosphatemia without altering the muscle tissue P homeostasis or causing clinically apparent muscle function disturbances.     

基于表面肌电的肌肉舒适度评价准则

为了避免操作人员长期处于较差的姿势工作,选取人体上身5个关节进行动作试验,对每个动作变化起主要作用的肌肉块进行了肌电信号测试。通过最大主动收缩法消除不同受试者的肌电信号差异,对肌电百分比值进行归一化和加权平均法处理,根据每个动作变化涉及肌肉的平均生理横断面积,给出复合动作肌肉舒适度指数的计算方法;提出了一套基于表面肌电的肌肉舒适度评价准则,与DELMIA人机仿真软件中的RULA分析结果对比显示,该评价准则具有可行性,适合对操作人员的作业姿势进行评价。     

Electromyographic evidence for age-related differences in the mimicry of anger.

Although older adults have difficulty recognizing all facial emotions, they have particular difficulty decoding expressions of anger. Since disruption of facial mimicry impairs emotion recognition, electromyography of the corrugator supercilii (i.e., brow) muscle region was used to test whether there are age differences in anger mimicry. Associations between mimicry and emotion recognition were also assessed. The results indicated that although there were no age differences in anger mimicry, older (but not young) adults' corrugator responses to angry expressions were associated with reduced anger recognition. Implications for understanding emotion recognition difficulties in older adulthood are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

基于Bayes决策理论的表面肌电信号模式分类的研究

通过对采集的四通道表面肌电信号进行分析,对其建立AR（Autoregressive）参数模型,提取AR模型参数构建特征矢量。根据实际表面肌电（SEMG）信号的随机性特征,提出了一种采用Bayes决策理论对肌电信号的AR模型参数特征进行分类的新方法,并运用最小错误率Bayes分类器,很好地实现了对前臂八种动作表面肌电信号的模式分类。平均识别率为99．125％。此外,还提出采用动态聚类中心的方法对其进行了改进,使其平均识别率提高到99．5％。研究表明,采用Bayes分类器对肌电信号的AR模型参数特征进行分类,是一种有效的处理手段,并可直接应用到其它具有随机性特征的生理电信号的模式分类中。     

一种表面肌电信号测试电路设计

表面肌电信号(SEMG)是一种伴随肌肉活动在皮肤表面产生的生物电信号,它蕴涵了许多肢体运动的信息,对其进行模式信息处理可以获得人-机仿生系统的控制信号.SEMG的特点是内阻高,影响因素多,并极易受到干扰.本文在分析肌电信号产生机理的基础上,给出了一种SEMG的采集、放大和滤波电路.对信号处理电路的特性分析表明,所设计的处理电路可以有效提取(10～500)Hz的肌电信号,并能对50 Hz的工频干扰起到很好的抑制作用,该电路在实际应用时取得了理想的实验结果,信号的采集能力和信噪比达到或接近美国kistler公司的肌电采集仪水平.     

步态分析研究综述

目的 梳理步态分析的发展脉络,介绍步态分析中常用的实验和仿真方法,了解步态分析的主要应用领域,预测步态分析未来的发展方向。方法 收集步态分析领域的国内外主要文献,梳理该领域的主要研究内容、研究方法、研究现状和主要应用领域。结果 步态分析的主要研究内容是对运动学、动力学参数及其变化规律的定量研究,多数学者将研究集中在临床诊断与康复评价、穿戴式机器人及康复辅具研发与竞技体育科学训练方式探索上;步态分析的研究方法包括实验研究和仿真分析法;步态分析的研究成果可以为医疗领域中相关疾病的临床诊断、疗效评估和康复训练提供指导意见,为工程领域中双足机器人、助行器及康复辅具、人工关节的设计开发提供数据支撑。结论 未来步态分析手段将更精准、应用领域将更广泛,步态分析的应用也将扩展到更多领域,工业设计也将持续引入步态分析的方法与成果,为用户带来更好的产品和更舒适的体验。     

基于表面肌电信号形态特征的多模式识别研究

为提高肢体运动模式识别率,基于肌电信号的产生机理提出了选用信号的形态特征实现肌电信号模式识别的新方案。方案以分形理论中关联维及分维数的概念分别表征肌电信号的复杂度及自相似性,其中关联维的计算采用了一种改进的G-P算法、即G-P关联维逼近法;在手部动作模式识别中,以关联维和分维数作为表面肌电信号的特征向量,分类器采用由对支持向量机构造的二叉树结构多类分类器。针对手部张开、合拢及腕伸、腕屈4种运动模式的识别实验,该方法的正确识别率达到了91.0%,已具备一定的实用性。     

改进的P SO-SVM在表面肌电信号模式识别中的研究

为了提高表面肌电信号的遥操作机械手运动模式识别率,设优化支持向量机(IPSO-SVM).该方法首先简化PSO的位置和速度公式,然后提出ESE状态估计策略判断算法的"早熟"收敛,最后对6类手臂运动模式(握拳、展拳、内旋、外旋、屈腕、伸腕)进行分类并与另外4个测试算法的分类结果进行比较.实验结果表明:IPSO-SVM算法的平均准确率为93.75%,而传统SVM算法的平均准确率为70.21%;算法的训练时间和泛化时间都有明显的提高;具有较强的鲁棒性和抗干扰能力.因此IPSO-SVM算法可以很好的解决表面肌电信号的动作模式分类问题,具有很好的应用价值.