External Sensors for Detecting the Activation and Deactivation Times of the Major Muscles Used in Walking
External Sensors for Detecting the Activation and Deactivation Times of the Major Muscles Used in Walking
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DOI：
10.1109/tnsre.2012.2203338
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发表时间：
2012-07-01
影响因子：
4.9
通讯作者：
Stein, Richard B.
中科院分区：
文献类型：
--
作者：
Lovse, Lisa;Bobet, Jacques;Stein, Richard B.
功能性电刺激（FES）可以改善行动不便者的行走。我们评估了加速度计、力敏电阻器、节段角度和节段角速度，以确定哪种传感器最能确定步行过程中使用的主要肌肉的激活和失活时间。这种传感器将来可以与FES系统结合使用，以改善行走。身体健全的受试者以不同的速度行走。为每个传感器设置阈值水平，使激活和停用六块肌肉的肌电图（EMG）的时间与传感器阈值交叉的时间之间的差异最小化，以步进周期的百分比表示。行动不便的受试者以他们喜欢的速度行走，有和没有FES纠正足下垂。为这些受试者设置了交叉点，以便传感器信号在与身体健全的受试者相匹配的时间交叉。节段角度通常是最有效的传感器信号。利用大腿、小腿和足部的节段角度，可以确定六块肌肉的激活和失活时间在步周期的6%以内。小腿节段角度产生的总体误差最低，并且在12个事件中的10个事件（六个肌肉群的激活和失活）中是前三名传感器之一。使用互补滤波器（加速度计/陀螺仪组合）实现了分段角度传感器。与单独使用加速度计相比，使用该传感器改善了足下垂受试者基于规则的FES计时。
Functional electrical stimulation (FES) can improve walking in individuals with mobility impairments. We evaluated accelerometers, force sensitive resistors, segment angles, and segment angular velocities to identify which sensor best determines the activation and deactivation times of the main muscles used during walking. This sensor(s) can be used in the future in conjunction with FES systems to improve walking. Able-bodied subjects walked at various speeds. Threshold levels were set for each sensor that minimized the difference between the times of activating and deactivating the electromyogram (EMG) of six muscles and the times of sensor threshold crossings as a percent of the step cycle. Mobility-impaired subjects walked at their preferred speed with and without FES to correct foot drop. Thresholds were set for these subjects so that sensor signals would cross at times that matched those of able-bodied subjects. Segment angles were generally the most effective sensor signals. Using segment angles of the thigh, shank, and foot, activation and deactivation times of the six muscles could be determined to within 6% of the step cycle. The shank segment angle produced the lowest overall error and was among the top three sensors for 10 of the 12 events (activation and deactivation of six muscle groups). A segment angle sensor was implemented using a complementary filter (accelerometer/gyroscope combination). Using this sensor improved rule-based timing of FES in subjects with foot drop as compared to accelerometers alone.