Turmell-Meter: A Device for Estimating the Subtalar and Talocrural Axes of the Human Ankle Joint by Applying the Product of Exponentials Formula

The human ankle is a complex joint, most commonly represented as the talocrural and subtalar axes. It is troublesome to take in vivo measurements of the ankle joint. There are no instruments for patients lying on flat surfaces; employed in outdoor or remote sites. We have developed a “Turmell-meter”...

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Main Authors: Óscar Agudelo-Varela, Julio Vargas-Riaño, Ángel Valera
Format: Article
Language:English
Published: MDPI AG 2022-05-01
Series:Bioengineering
Subjects:
Online Access:https://www.mdpi.com/2306-5354/9/5/199
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author Óscar Agudelo-Varela
Julio Vargas-Riaño
Ángel Valera
author_facet Óscar Agudelo-Varela
Julio Vargas-Riaño
Ángel Valera
author_sort Óscar Agudelo-Varela
collection DOAJ
description The human ankle is a complex joint, most commonly represented as the talocrural and subtalar axes. It is troublesome to take in vivo measurements of the ankle joint. There are no instruments for patients lying on flat surfaces; employed in outdoor or remote sites. We have developed a “Turmell-meter” to address these issues. It started with the study of ankle anatomy and anthropometry. We also use the product of exponentials’ formula to visualize the movements. We built a prototype using human proportions and statistics. For pose estimation, we used a trilateration method by applying tetrahedral geometry. We computed the axis direction by fitting circles in 3D, plotting the manifold and chart as an ankle joint model. We presented the results of simulations, a prototype comprising 45 parts, specifically designed draw-wire sensors, and electronics. Finally, we tested the device by capturing positions and fitting them into the bi-axial ankle model as a Riemannian manifold. The Turmell-meter is a hardware platform for human ankle joint axes estimation. The measurement accuracy and precision depend on the sensor quality; we address this issue by designing an electronics capture circuit, measuring the real measurement with a Vernier caliper. Then, we adjust the analog voltages and filter the 10-bit digital value. The Technology Readiness Level is 2. The proposed ankle joint model has the properties of a chart in a geometric manifold, and we provided the details.
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spelling doaj.art-15eb1baa2cd9484c8dc8127c5d5884b42023-11-23T10:05:38ZengMDPI AGBioengineering2306-53542022-05-019519910.3390/bioengineering9050199Turmell-Meter: A Device for Estimating the Subtalar and Talocrural Axes of the Human Ankle Joint by Applying the Product of Exponentials FormulaÓscar Agudelo-Varela0Julio Vargas-Riaño1Ángel Valera2Facultad de Ciencias Básicas e Ingeniería, Universidad de los Llanos, Villavicencio 500002, ColombiaInstituto Universitario de Automática e Informática Industrial (Instituto ai2), Universitat Politècnica de València, 46022 Valencia, SpainInstituto Universitario de Automática e Informática Industrial (Instituto ai2), Universitat Politècnica de València, 46022 Valencia, SpainThe human ankle is a complex joint, most commonly represented as the talocrural and subtalar axes. It is troublesome to take in vivo measurements of the ankle joint. There are no instruments for patients lying on flat surfaces; employed in outdoor or remote sites. We have developed a “Turmell-meter” to address these issues. It started with the study of ankle anatomy and anthropometry. We also use the product of exponentials’ formula to visualize the movements. We built a prototype using human proportions and statistics. For pose estimation, we used a trilateration method by applying tetrahedral geometry. We computed the axis direction by fitting circles in 3D, plotting the manifold and chart as an ankle joint model. We presented the results of simulations, a prototype comprising 45 parts, specifically designed draw-wire sensors, and electronics. Finally, we tested the device by capturing positions and fitting them into the bi-axial ankle model as a Riemannian manifold. The Turmell-meter is a hardware platform for human ankle joint axes estimation. The measurement accuracy and precision depend on the sensor quality; we address this issue by designing an electronics capture circuit, measuring the real measurement with a Vernier caliper. Then, we adjust the analog voltages and filter the 10-bit digital value. The Technology Readiness Level is 2. The proposed ankle joint model has the properties of a chart in a geometric manifold, and we provided the details.https://www.mdpi.com/2306-5354/9/5/199human ankle modelproduct of exponentials formulaanthropometrybiomechanicscoordinate measuring machineskinematics
spellingShingle Óscar Agudelo-Varela
Julio Vargas-Riaño
Ángel Valera
Turmell-Meter: A Device for Estimating the Subtalar and Talocrural Axes of the Human Ankle Joint by Applying the Product of Exponentials Formula
Bioengineering
human ankle model
product of exponentials formula
anthropometry
biomechanics
coordinate measuring machines
kinematics
title Turmell-Meter: A Device for Estimating the Subtalar and Talocrural Axes of the Human Ankle Joint by Applying the Product of Exponentials Formula
title_full Turmell-Meter: A Device for Estimating the Subtalar and Talocrural Axes of the Human Ankle Joint by Applying the Product of Exponentials Formula
title_fullStr Turmell-Meter: A Device for Estimating the Subtalar and Talocrural Axes of the Human Ankle Joint by Applying the Product of Exponentials Formula
title_full_unstemmed Turmell-Meter: A Device for Estimating the Subtalar and Talocrural Axes of the Human Ankle Joint by Applying the Product of Exponentials Formula
title_short Turmell-Meter: A Device for Estimating the Subtalar and Talocrural Axes of the Human Ankle Joint by Applying the Product of Exponentials Formula
title_sort turmell meter a device for estimating the subtalar and talocrural axes of the human ankle joint by applying the product of exponentials formula
topic human ankle model
product of exponentials formula
anthropometry
biomechanics
coordinate measuring machines
kinematics
url https://www.mdpi.com/2306-5354/9/5/199
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AT juliovargasriano turmellmeteradeviceforestimatingthesubtalarandtalocruralaxesofthehumananklejointbyapplyingtheproductofexponentialsformula
AT angelvalera turmellmeteradeviceforestimatingthesubtalarandtalocruralaxesofthehumananklejointbyapplyingtheproductofexponentialsformula