Impact-Aware Foot Motion Reconstruction and Ramp/Stair Detection Using One Foot-Mounted Inertial Measurement Unit

Motion reconstruction using wearable sensors enables broad opportunities for gait analysis outside laboratory environments. Inertial Measurement Unit (IMU)-based foot trajectory reconstruction is an essential component of estimating the foot motion and user position required for any related biomecha...

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Main Authors: Yisen Wang, Katherine H. Fehr, Peter G. Adamczyk
Format: Article
Language:English
Published: MDPI AG 2024-02-01
Series:Sensors
Subjects:
Online Access:https://www.mdpi.com/1424-8220/24/5/1480
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author Yisen Wang
Katherine H. Fehr
Peter G. Adamczyk
author_facet Yisen Wang
Katherine H. Fehr
Peter G. Adamczyk
author_sort Yisen Wang
collection DOAJ
description Motion reconstruction using wearable sensors enables broad opportunities for gait analysis outside laboratory environments. Inertial Measurement Unit (IMU)-based foot trajectory reconstruction is an essential component of estimating the foot motion and user position required for any related biomechanics metrics. However, limitations remain in the reconstruction quality due to well-known sensor noise and drift issues, and in some cases, limited sensor bandwidth and range. In this work, to reduce drift in the height direction and handle the impulsive velocity error at heel strike, we enhanced the integration reconstruction with a novel kinematic model that partitions integration velocity errors into estimates of acceleration bias and heel strike vertical velocity error. Using this model, we achieve reduced height drift in reconstruction and simultaneously accomplish reliable terrain determination among level ground, ramps, and stairs. The reconstruction performance of the proposed method is compared against the widely used Error State Kalman Filter-based Pedestrian Dead Reckoning and integration-based foot-IMU motion reconstruction method with 15 trials from six subjects, including one prosthesis user. The mean height errors per stride are <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>0.03</mn><mo>±</mo><mn>0.08</mn><mtext> </mtext><mi mathvariant="normal">c</mi><mi mathvariant="normal">m</mi></mrow></semantics></math></inline-formula> on level ground, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>0.95</mn><mo>±</mo><mn>0.37</mn><mtext> </mtext><mi mathvariant="normal">c</mi><mi mathvariant="normal">m</mi></mrow></semantics></math></inline-formula> on ramps, and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>1.27</mn><mo>±</mo><mn>1.22</mn><mtext> </mtext><mi mathvariant="normal">c</mi><mi mathvariant="normal">m</mi></mrow></semantics></math></inline-formula> on stairs. The proposed method can determine the terrain types accurately by thresholding on the model output and demonstrates great reconstruction improvement in level-ground walking and moderate improvement on ramps and stairs.
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spelling doaj.art-d38a94b24d724e10b9d1d0255b973d502024-03-12T16:54:54ZengMDPI AGSensors1424-82202024-02-01245148010.3390/s24051480Impact-Aware Foot Motion Reconstruction and Ramp/Stair Detection Using One Foot-Mounted Inertial Measurement UnitYisen Wang0Katherine H. Fehr1Peter G. Adamczyk2Department of Mechanical Engineering, University of Wisconsin–Madison, Madison, WI 53706, USADepartment of Mechanical Engineering, University of Wisconsin–Madison, Madison, WI 53706, USADepartment of Mechanical Engineering, University of Wisconsin–Madison, Madison, WI 53706, USAMotion reconstruction using wearable sensors enables broad opportunities for gait analysis outside laboratory environments. Inertial Measurement Unit (IMU)-based foot trajectory reconstruction is an essential component of estimating the foot motion and user position required for any related biomechanics metrics. However, limitations remain in the reconstruction quality due to well-known sensor noise and drift issues, and in some cases, limited sensor bandwidth and range. In this work, to reduce drift in the height direction and handle the impulsive velocity error at heel strike, we enhanced the integration reconstruction with a novel kinematic model that partitions integration velocity errors into estimates of acceleration bias and heel strike vertical velocity error. Using this model, we achieve reduced height drift in reconstruction and simultaneously accomplish reliable terrain determination among level ground, ramps, and stairs. The reconstruction performance of the proposed method is compared against the widely used Error State Kalman Filter-based Pedestrian Dead Reckoning and integration-based foot-IMU motion reconstruction method with 15 trials from six subjects, including one prosthesis user. The mean height errors per stride are <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>0.03</mn><mo>±</mo><mn>0.08</mn><mtext> </mtext><mi mathvariant="normal">c</mi><mi mathvariant="normal">m</mi></mrow></semantics></math></inline-formula> on level ground, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>0.95</mn><mo>±</mo><mn>0.37</mn><mtext> </mtext><mi mathvariant="normal">c</mi><mi mathvariant="normal">m</mi></mrow></semantics></math></inline-formula> on ramps, and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>1.27</mn><mo>±</mo><mn>1.22</mn><mtext> </mtext><mi mathvariant="normal">c</mi><mi mathvariant="normal">m</mi></mrow></semantics></math></inline-formula> on stairs. The proposed method can determine the terrain types accurately by thresholding on the model output and demonstrates great reconstruction improvement in level-ground walking and moderate improvement on ramps and stairs.https://www.mdpi.com/1424-8220/24/5/1480integration reconstructioninertial sensorsramp/stair detectionheel strike
spellingShingle Yisen Wang
Katherine H. Fehr
Peter G. Adamczyk
Impact-Aware Foot Motion Reconstruction and Ramp/Stair Detection Using One Foot-Mounted Inertial Measurement Unit
Sensors
integration reconstruction
inertial sensors
ramp/stair detection
heel strike
title Impact-Aware Foot Motion Reconstruction and Ramp/Stair Detection Using One Foot-Mounted Inertial Measurement Unit
title_full Impact-Aware Foot Motion Reconstruction and Ramp/Stair Detection Using One Foot-Mounted Inertial Measurement Unit
title_fullStr Impact-Aware Foot Motion Reconstruction and Ramp/Stair Detection Using One Foot-Mounted Inertial Measurement Unit
title_full_unstemmed Impact-Aware Foot Motion Reconstruction and Ramp/Stair Detection Using One Foot-Mounted Inertial Measurement Unit
title_short Impact-Aware Foot Motion Reconstruction and Ramp/Stair Detection Using One Foot-Mounted Inertial Measurement Unit
title_sort impact aware foot motion reconstruction and ramp stair detection using one foot mounted inertial measurement unit
topic integration reconstruction
inertial sensors
ramp/stair detection
heel strike
url https://www.mdpi.com/1424-8220/24/5/1480
work_keys_str_mv AT yisenwang impactawarefootmotionreconstructionandrampstairdetectionusingonefootmountedinertialmeasurementunit
AT katherinehfehr impactawarefootmotionreconstructionandrampstairdetectionusingonefootmountedinertialmeasurementunit
AT petergadamczyk impactawarefootmotionreconstructionandrampstairdetectionusingonefootmountedinertialmeasurementunit