Accuracy of Base of Support Using an Inertial Sensor Based Motion Capture System.

Liangjie Guo,Shuping Xiong

doi:10.3390/s17092091

Abstract

The potential of miniature inertial sensors for human balance and gait analysis appears promising. Base of support (BOS), together with its interaction with center of mass, is a critical indicator in above mentioned research fields. This study aims to evaluate the accuracy of Xsens MVN BIOMECH, a commercial widely used inertial sensor-based motion capture system, for measuring static BOS and examine the effect of different task complexity on the accuracy. Eleven young males participated in this study and went through eleven different experimental tasks. Results showed there were considerable errors in estimating BOS area (error ranged from −12.6% to +64.6%) from Xsens MVN and a large error in foot separation distance when there was knee flexion. The estimated BOS area from MVN was smaller than the ground truth from footprint when there was no knee flexion, and larger when there was knee flexion, and it increased monotonically along with the knee flexion angles. Wrongly estimated foot separations, mainly caused by knee flexion, and the initial system estimation error on BOS, were two major reasons for error and instability of BOS estimation. The findings suggested that caution should be taken when using Xsens MVN BIOMECH to estimate BOS and foot position-related measurements, especially for postures/motions with knee flexion.

Highlights

Miniature inertial sensors are cost effective, wearable, compact and lightweight, and have been widely used in many fields
The findings suggested that caution should be taken when using Xsens MVN BIOMECH to estimate
We focus on static Base of support (BOS) with different body postures/motions due to the following reasons: (1) static BOS is easy to obtain and measure without complex experimental setup; (2) static BOS at different body postures is an important variable used by many studies for assessing human balance and postural stability [54,55,56]; (3) having good accuracy on static BOS should be a necessary condition for acceptable accuracy on dynamic BOS for

Summary

Introduction

Miniature inertial sensors are cost effective, wearable, compact and lightweight, and have been widely used in many fields. The Xsens MVN BIOMECH (Xsens Technologies B.V., Enschede, The. Netherlands) is a commercially available inertial sensor-based motion capture system composed of 17 miniature inertial sensors placed over the full body [4,5]. Netherlands) is a commercially available inertial sensor-based motion capture system composed of 17 miniature inertial sensors placed over the full body [4,5] It has been widely used in the research fields of biomechanics [6,7,8,9], ergonomics and human factors [10,11], sports science [12,13,14,15,16,17,18] and virtual or augmented reality [19,20,21]. Xsens MVN has a good accuracy in human kinematics estimation, such as joint angle and segment orientation [22,23,24,25,26], it has been validated against optical motion capture system [7,26,27] and is currently considered as the ‘gold reference’ for kinematics measurements [28,29]

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