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摘要: 传统基于肌电(Electromyography,EMG)的运动识别方法多是利用训练后的固定参数模型,分类已预先定义的有限个目标动作,但对肌肉疲劳导致的肌电变化,以及未定义的外部动作等干扰因素无能为力.针对这一问题,提出一种自更新混合分类模型(Self-update hybrid classification model,SUHC),该模型融合了用于排除外部动作干扰的一类支持向量机(Support vector machine,SVM),以及用于分类目标动作数据的多类线性判别分析(Linear discriminant analysis,LDA),并引入自更新机制以对抗肌电时变性干扰.通过手部动作识别实验验证提出方法的效果,在肌电大幅变化干扰下,SUHC的目标动作识别精度达到89%,对比传统的支持向量机、多层感知器(Multiple layer perceptron,MLP)和核线性判别分析(Kernel LDA,KLDA),提高了约18%,并且SUHC具备排除外部动作干扰能力,排除精度高达93%.Abstract: The traditional electromyography (EMG)-based motion recognition methods always classify a limited number of pre-defined target motions by using a trained parameter-fixed model. However, those methods have no ability to handle the interference factors, including changes of EMG signals caused by muscle fatigue and outlier motions undefined beforehand. For this problem, a self-update hybrid classification model (SUHC) is proposed. In the SUHC, the one-class support vector machine (SVM) that can reject outlier motions is combined to a multi-class linear discriminant analysis (LDA) that is used to recognize target motions; furthermore, a self-update mechanism is adopted to reduce the influence caused by EMG changes. The performance of the proposed method is verified by the experiment of EMG-based hand motion recognition. Under the interference that EMG signals vary greatly, the recognition accuracy of SUHC on target motions is about 89%, which is 18% higher than those of the normal SVM, multiple layer perceptron (MLP) and kernel LDA (KLDA); moreover, the SUHC has the ability to reject outlier motions with a 93% of rejection accuracy.1) 本文责任编委 李鸿一
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表 1 使用所有测试者的10组测试样本计算的平均分类精度与标准差(%)
Table 1 The mean classification accuracies and standard deviations calculated by using the ten sessions of test data of all subjects (%)
SUHC SVM MLP KLDA 1 ${\bf{91.5\pm4.3}}$ $89.3\pm5.1$ $90.4\pm2.9$ $89.8\pm5.9$ 2 ${\bf{89.1\pm2.6}}$ $85.1\pm7.5$ $81.7\pm6.4$ $83.4\pm8.1$ 3 ${\bf{88.7\pm6.6}}$ $75.3\pm10.4$ $74.3\pm8.8$ $77.1\pm10.7$ 4 ${\bf{86.2\pm4.1}}$ $70.8\pm14.4$ $71.2\pm10.7$ $72.7\pm11.2$ 5 ${\bf{93.4\pm3.8}}$ $73.0\pm9.1$ $70.7\pm13.5$ $71.5\pm14.6$ 6 ${\bf{88.5\pm6.2}}$ $69.8\pm12.9$ $64.2\pm11.2$ $67.3\pm11.9$ 7 ${\bf{86.0\pm5.7}}$ $59.9\pm12.3$ $59.5\pm12.1$ $62.1\pm13.4$ 8 ${\bf{88.1\pm8.4}}$ $61.7\pm10.2$ $57.8\pm13.0$ $59.4\pm14.7$ 9 ${\bf{91.4\pm4.9}}$ $58.4\pm9.7$ $60.1\pm10.6$ $61.6\pm9.2$ 10 ${\bf{87.9\pm4.3}}$ $62.8\pm10.3$ $57.0\pm15.6$ $58.1\pm13.9$ $m\pm st$ ${\bf{89.1\pm5.1}}$ $70.6\pm10.2$ $68.7\pm10.5$ $70.3\pm11.4$ 表 2 使用所有测试者的测试数据计算的分类精度与排除精度的均值和标准差(%)
Table 2 The means and standard deviations of classification and rejection accuracies computed by using the test data of all subjects (%)
目标动作分类精度 外部动作排除精度 SUHC $90.4\pm4.4$ $93.5\pm3.0$ SVDD $82.1\pm8.7$ $91.9\pm5.2$ SVM $62.5\pm16.1$ $-$ MLP $60.8\pm18.4$ $-$ KLDA $60.1\pm15.7$ $-$ -
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