Faculty of Electrical Engineering, Mathematics and Computer Science, University of Twente, Enschede, The Netherlands.
Department of Rehabilitation Medicine, Amsterdam Movement Sciences, VU University Medical Center, Amsterdam, The Netherlands.
J Neuroeng Rehabil. 2021 Feb 17;18(1):37. doi: 10.1186/s12984-021-00816-4.
The foot progression angle is an important measure used to help patients reduce their knee adduction moment. Current measurement systems are either lab-bounded or do not function in all environments (e.g., magnetically distorted). This work proposes a novel approach to estimate foot progression angle using a single foot-worn inertial sensor (accelerometer and gyroscope).
The approach uses a dynamic step frame that is recalculated for the stance phase of each step to calculate the foot trajectory relative to that frame, to minimize effects of drift and to eliminate the need for a magnetometer. The foot progression angle (FPA) is then calculated as the angle between walking direction and the dynamic step frame. This approach was validated by gait measurements with five subjects walking with three gait types (normal, toe-in and toe-out).
The FPA was estimated with a maximum mean error of ~ 2.6° over all gait conditions. Additionally, the proposed inertial approach can significantly differentiate between the three different gait types.
The proposed approach can effectively estimate differences in FPA without requiring a heading reference (magnetometer). This work enables feedback applications on FPA for patients with gait disorders that function in any environment, i.e. outside of a gait lab or in magnetically distorted environments.
足进角是一种重要的测量方法,可帮助患者减少膝关节内收力矩。目前的测量系统要么是实验室限制的,要么不能在所有环境下工作(例如,受磁场干扰)。本研究提出了一种使用单足穿戴惯性传感器(加速度计和陀螺仪)来估计足进角的新方法。
该方法使用动态步幅框架,为每个步幅的站立阶段重新计算该框架,以计算足轨迹相对于该框架的位置,从而最小化漂移的影响,并消除对磁力计的需求。然后,将足进角(FPA)计算为行走方向与动态步幅框架之间的角度。该方法通过 5 名受试者以三种步态类型(正常、内八字和外八字)行走时的步态测量进行验证。
在所有步态条件下,FPA 的最大平均误差约为 2.6°。此外,所提出的惯性方法可以显著区分三种不同的步态类型。
该方法无需航向参考(磁力计)即可有效估计 FPA 的差异。这项工作为步态障碍患者提供了在任何环境下(即不在步态实验室或受磁场干扰的环境下)工作的 FPA 反馈应用。