Optimization of MIMU Mounting Position on Shank in Posture Estimation Considering Muscle Protuberance

The influence of the mounting position of a magnetic-inertial measurement unit (MIMU) on the accuracy of posture estimation for a shank has not been extensively studied and remains unknown. In this study, we conducted comparative experiments using three MIMU positions: the lateral and frontal positi...

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Main Authors: Shun Kanega, Yoshihiro Muraoka
Format: Article
Language:English
Published: MDPI AG 2025-04-01
Series:Sensors
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Online Access:https://www.mdpi.com/1424-8220/25/7/2273
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author Shun Kanega
Yoshihiro Muraoka
author_facet Shun Kanega
Yoshihiro Muraoka
author_sort Shun Kanega
collection DOAJ
description The influence of the mounting position of a magnetic-inertial measurement unit (MIMU) on the accuracy of posture estimation for a shank has not been extensively studied and remains unknown. In this study, we conducted comparative experiments using three MIMU positions: the lateral and frontal positions, which are commonly used, and the medial tibial position, which is less affected by muscle protuberance, considering the anatomical structure of the body. To determine the optimal MIMU mounting position on the shank, we repeatedly performed plantar–dorsiflexion and relaxation of the ankle joint in a chair-sitting position and examined the effect of muscle contraction on the posture of the MIMU (Experiment 1). We also performed posture estimation during gait and compared the three-dimensional shank posture measured by the MIMU and optical motion capture to evaluate the estimation accuracy for each mounting position (Experiment 2). In Experiment 1, the orientation change at the medial tibia was significantly smaller than that at the other positions, showing an 80% reduction compared with the anterior tibia during dorsiflexion. In Experiment 2, the medial tibia achieved the highest estimation accuracy, showing a 13% lower RMSE than that of the anterior position. The results of these two experiments suggest that the medial tibia is the optimal position on the shank, as the posture estimation accuracy was the highest when the MIMU was mounted on the medial tibia, where there was no muscle under the mounting surface. Moreover, the posture estimation accuracy was less affected by muscle protuberance under these conditions.
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spelling doaj-art-9a624ec303d74f35982fc0dfc5968f182025-08-20T03:08:54ZengMDPI AGSensors1424-82202025-04-01257227310.3390/s25072273Optimization of MIMU Mounting Position on Shank in Posture Estimation Considering Muscle ProtuberanceShun Kanega0Yoshihiro Muraoka1Faculty of Human Sciences, Waseda University, Tokorozawa 359-1192, JapanFaculty of Human Sciences, Waseda University, Tokorozawa 359-1192, JapanThe influence of the mounting position of a magnetic-inertial measurement unit (MIMU) on the accuracy of posture estimation for a shank has not been extensively studied and remains unknown. In this study, we conducted comparative experiments using three MIMU positions: the lateral and frontal positions, which are commonly used, and the medial tibial position, which is less affected by muscle protuberance, considering the anatomical structure of the body. To determine the optimal MIMU mounting position on the shank, we repeatedly performed plantar–dorsiflexion and relaxation of the ankle joint in a chair-sitting position and examined the effect of muscle contraction on the posture of the MIMU (Experiment 1). We also performed posture estimation during gait and compared the three-dimensional shank posture measured by the MIMU and optical motion capture to evaluate the estimation accuracy for each mounting position (Experiment 2). In Experiment 1, the orientation change at the medial tibia was significantly smaller than that at the other positions, showing an 80% reduction compared with the anterior tibia during dorsiflexion. In Experiment 2, the medial tibia achieved the highest estimation accuracy, showing a 13% lower RMSE than that of the anterior position. The results of these two experiments suggest that the medial tibia is the optimal position on the shank, as the posture estimation accuracy was the highest when the MIMU was mounted on the medial tibia, where there was no muscle under the mounting surface. Moreover, the posture estimation accuracy was less affected by muscle protuberance under these conditions.https://www.mdpi.com/1424-8220/25/7/2273IMUMIMUoptimal positionshankgaitpacemaker
spellingShingle Shun Kanega
Yoshihiro Muraoka
Optimization of MIMU Mounting Position on Shank in Posture Estimation Considering Muscle Protuberance
Sensors
IMU
MIMU
optimal position
shank
gait
pacemaker
title Optimization of MIMU Mounting Position on Shank in Posture Estimation Considering Muscle Protuberance
title_full Optimization of MIMU Mounting Position on Shank in Posture Estimation Considering Muscle Protuberance
title_fullStr Optimization of MIMU Mounting Position on Shank in Posture Estimation Considering Muscle Protuberance
title_full_unstemmed Optimization of MIMU Mounting Position on Shank in Posture Estimation Considering Muscle Protuberance
title_short Optimization of MIMU Mounting Position on Shank in Posture Estimation Considering Muscle Protuberance
title_sort optimization of mimu mounting position on shank in posture estimation considering muscle protuberance
topic IMU
MIMU
optimal position
shank
gait
pacemaker
url https://www.mdpi.com/1424-8220/25/7/2273
work_keys_str_mv AT shunkanega optimizationofmimumountingpositiononshankinpostureestimationconsideringmuscleprotuberance
AT yoshihiromuraoka optimizationofmimumountingpositiononshankinpostureestimationconsideringmuscleprotuberance