用单对肌电传感器实现精准握力预测,助力康复机器人实时调节输出。
Koopman-driven grip force prediction through EMG sensing
- 基于科普曼算子理论和数据提升技术,从肌电信号推断握力。
- 预测误差仅5.5%(0.5秒预测窗口下为17.9%),精度高。
- 对电极位置不敏感,处理速度快,适合实时康复应用。
因中风或多发性硬化等疾病导致的手部功能丧失严重影响日常生活。机器人康复可帮助恢复手功能,而基于表面肌电(sEMG)的新方法能根据用户状态动态调整设备输出力,从而提升康复效果。本研究旨在仅用一对sEMG传感器实现中等包裹抓握时的精准力估计,解决高精度预测所需传感器数量增加的问题。在13名受试者上于两个前臂位置采集了sEMG数据,并通过手力计验证结果。通过灵活的信号处理流程,使处理后的sEMG信号与握力间的峰值互相关性显著提高。经敏感性分析识别出关键参数。采用基于数据驱动的科普曼算子理论与特定问题的数据提升技术,构建了从处理后sEMG信号估计并短期预测握力的方法。对估计握力的加权平均绝对百分比误差(wMAPE)约为5.5%,0.5秒预测窗口下的wMAPE约为17.9%。该方法对电极精确定位不敏感,定位误差对误差指标无显著影响。算法执行极快,约30毫秒内完成0.5秒信号批次的处理、估计与预测,支持实时部署。
原文摘要 · Abstract (English)
Loss of hand function due to conditions like stroke or multiple sclerosis significantly impacts daily activities. Robotic rehabilitation provides tools to restore hand function, while novel methods based on surface electromyography (sEMG) enable the adaptation of the device's force output according to the user's condition, thereby improving rehabilitation outcomes. This study aims to achieve accurate force estimations during medium wrap grasps using a single sEMG sensor pair, thereby addressing the challenge of escalating sensor requirements for precise predictions. We conducted sEMG measurements on 13 subjects at two forearm positions, validating results with a hand dynamometer. We established flexible signal-processing steps, yielding high peak cross-correlations between the processed sEMG signal (representing meaningful muscle activity) and grip force. Influential parameters were subsequently identified through sensitivity analysis. Leveraging a novel data-driven Koopman operator theory-based approach and problem-specific data lifting techniques, we devised a methodology for the estimation and short-term prediction of grip force from processed sEMG signals. A weighted mean absolute percentage error (wMAPE) of approx. 5.5% was achieved for the estimated grip force, whereas predictions with a 0.5-second prediction horizon resulted in a wMAPE of approx. 17.9%. The methodology proved robust regarding precise electrode positioning, as the effect of sensing position on error metrics was non-significant. The algorithm executes exceptionally fast, processing, estimating, and predicting a 0.5-second sEMG signal batch in just approx. 30 ms, facilitating real-time implementation.
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