Department of Automatic Control and Systems Engineering, The University of Sheffield, Mappin Street, Sheffield S1 3JD, UK.
INSIGNEO Institute for in Silico Medicine, The University of Sheffield, Mappin Street, Sheffield S1 3JD, UK.
Sensors (Basel). 2017 Sep 22;17(10):2181. doi: 10.3390/s17102181.
Measurement of the ground reaction forces (GRF) during walking is typically limited to laboratory settings, and only short observations using wearable pressure insoles have been reported so far. In this study, a new proxy measurement method is proposed to estimate the vertical component of the GRF (vGRF) from wearable accelerometer signals. The accelerations are used as the proxy variable. An orthogonal forward regression algorithm (OFR) is employed to identify the dynamic relationships between the proxy variables and the measured vGRF using pressure-sensing insoles. The obtained model, which represents the connection between the proxy variable and the vGRF, is then used to predict the latter. The results have been validated using pressure insoles data collected from nine healthy individuals under two outdoor walking tasks in non-laboratory settings. The results show that the vGRFs can be reconstructed with high accuracy (with an average prediction error of less than 5.0%) using only one wearable sensor mounted at the waist (L5, fifth lumbar vertebra). Proxy measures with different sensor positions are also discussed. Results show that the waist acceleration-based proxy measurement is more stable with less inter-task and inter-subject variability than the proxy measures based on forehead level accelerations. The proposed proxy measure provides a promising low-cost method for monitoring ground reaction forces in real-life settings and introduces a novel generic approach for replacing the direct determination of difficult to measure variables in many applications.
测量行走时的地面反作用力（GRF）通常仅限于实验室环境，迄今为止，仅报道了使用可穿戴压力鞋垫进行的短期观察。在这项研究中，提出了一种新的代理测量方法，从可穿戴加速度计信号中估计垂直分量的 GRF（vGRF）。加速度用作代理变量。使用正交前向回归算法（OFR）来识别代理变量与使用压力感应鞋垫测量的 vGRF 之间的动态关系。然后，使用所获得的模型（表示代理变量与 vGRF 之间的连接）来预测后者。使用在非实验室环境下在两个户外行走任务下从九名健康个体收集的压力鞋垫数据验证了结果。结果表明，仅使用安装在腰部（L5，第五腰椎）的一个可穿戴传感器即可高度准确地重建 vGRF（平均预测误差小于 5.0％）。还讨论了具有不同传感器位置的代理措施。结果表明，与基于前额水平加速度的代理测量相比，基于腰部加速度的代理测量更稳定，任务间和个体间的可变性更小。所提出的代理测量方法为在实际环境中监测地面反作用力提供了一种很有前途的低成本方法，并为在许多应用中替代难以测量的变量的直接确定提供了一种新颖的通用方法。
