使用可穿戴惯性传感器测量膝关节屈曲角度的重复性

Repeatability of measuring knee flexion angles with wearable inertial sensors.

作者信息

Fennema M C, Bloomfield R A, Lanting B A, Birmingham T B, Teeter M G

机构信息

Lawson Health Research Institute, Robarts Research Institute, Department of Medical Biophysics, Western University, London, ON, Canada.

Lawson Health Research Institute, Robarts Research Institute, Department of Electrical and Computer Engineering, Western University, London, ON, Canada.

出版信息

Knee. 2019 Jan;26(1):97-105. doi: 10.1016/j.knee.2018.11.002. Epub 2018 Dec 13.

DOI:10.1016/j.knee.2018.11.002

PMID:30554906

Abstract

BACKGROUND

As assessment with inertial-measurement-units (IMUs) increases in research and in clinics, it is important to be aware of the repeatability of these sensors. The objectives of this experiment were to evaluate the measurement repeatability of IMU joint angles using a repeatable robot controller and an anthropomorphic leg phantom and to determine effects of joint speed and sensor positioning on the angles collected by these sensors. Comparisons to an electro-goniometer and three-dimensional (3D) motion capture cameras were also completed.

METHODS

Two dual-IMU setups (posterior and lateral) were tested concurrently with an electro-goniometer and 3D motion capture cameras using a repeatable robot controller and a leg phantom. All modalities were attached to the phantom, which was flexed 10 times using a pre-programmed motion pathway during each test. Mean angles were compared across tests. Effects of joint speed, sensor re-positioning, and anatomical placement of the sensors on repeatability were assessed.

RESULTS

Re-positioning caused greater deviation to the maximum and minimum angles than differences in speed. Overall, the means ± standard deviations, and 95% confidence intervals of the maximum angles across all tests for the 3D camera markers, electro-goniometer, posterior IMUs, and lateral IMUs were 119.4 ± 0.3° (119.4, 119.5), 112.4 ± 0.5° (112.3, 112.5), 116.2 ± 2.4° (115.7, 116.7), and 118.3 ± 1.1° (118.1, 118.6).

CONCLUSIONS

Both posterior and lateral IMU setups demonstrated acceptable repeatability in measurement of range of motion that was advantageous to manual goniometer methods. Posterior and lateral IMU setups demonstrated overlapping standard deviations about their means.

摘要

背景

随着惯性测量单元（IMU）在研究和临床中的应用日益增加，了解这些传感器的可重复性非常重要。本实验的目的是使用可重复的机器人控制器和拟人化腿部模型评估IMU关节角度的测量可重复性，并确定关节速度和传感器位置对这些传感器采集角度的影响。还完成了与电子测角仪和三维（3D）运动捕捉相机的比较。

方法

使用可重复的机器人控制器和腿部模型，将两个双IMU设置（后侧和外侧）与电子测角仪和3D运动捕捉相机同时进行测试。所有模态均连接到模型上，在每次测试期间，模型使用预编程的运动路径弯曲10次。比较各测试之间的平均角度。评估关节速度、传感器重新定位以及传感器在解剖学位置上的放置对可重复性的影响。

结果

重新定位导致的最大和最小角度偏差大于速度差异导致的偏差。总体而言，3D相机标记、电子测角仪、后侧IMU和外侧IMU在所有测试中最大角度的均值±标准差以及95%置信区间分别为119.4±0.3°（119.4，119.5）、112.4±0.5°（112.3，112.5）、116.2±2.4°（115.7，116.7）和118.3±1.1°（118.1，118.6）。