Joint Angle Estimation of a Tendon-Driven Soft Wearable Robot through a Tension and Stroke Measurement

The size of a device and its adaptability to human properties are important factors in developing a wearable device. In wearable robot research, therefore, soft materials and tendon transmissions have been utilized to make robots compact and adaptable to the human body. However, when used for wearab...

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Main Authors: Byungchul Kim, Jiwon Ryu, Kyu-Jin Cho
Format: Article
Language:English
Published: MDPI AG 2020-05-01
Series:Sensors
Subjects:
Online Access:https://www.mdpi.com/1424-8220/20/10/2852
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author Byungchul Kim
Jiwon Ryu
Kyu-Jin Cho
author_facet Byungchul Kim
Jiwon Ryu
Kyu-Jin Cho
author_sort Byungchul Kim
collection DOAJ
description The size of a device and its adaptability to human properties are important factors in developing a wearable device. In wearable robot research, therefore, soft materials and tendon transmissions have been utilized to make robots compact and adaptable to the human body. However, when used for wearable robots, these methods sometimes cause uncertainties that originate from elongation of the soft material or from undefined human properties. In this research, to consider these uncertainties, we propose a data-driven method that identifies both kinematic and stiffness parameters using tension and wire stroke of the actuators. Through kinematic identification, a method is proposed to find the exact joint position as a function of the joint angle. Through stiffness identification, the relationship between the actuation force and the joint angle is obtained using Gaussian Process Regression (GPR). As a result, by applying the proposed method to a specific robot, the research outlined in this paper verifies how the proposed method can be used in wearable robot applications. This work examines a novel wearable robot named Exo-Index, which assists a human’s index finger through the use of three actuators. The proposed identification methods enable control of the wearable robot to result in appropriate postures for grasping objects of different shapes and sizes.
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spelling doaj.art-9efd97c9ad564488bd373f7fb2e192572023-11-20T00:45:31ZengMDPI AGSensors1424-82202020-05-012010285210.3390/s20102852Joint Angle Estimation of a Tendon-Driven Soft Wearable Robot through a Tension and Stroke MeasurementByungchul Kim0Jiwon Ryu1Kyu-Jin Cho2Biorobotics Laboratory, School of Mechanical and Aerospace Engineering, Seoul National University, Gwanak-ro 1, Gwanak-gu, Seoul 08826, KoreaBiorobotics Laboratory, School of Mechanical and Aerospace Engineering, Seoul National University, Gwanak-ro 1, Gwanak-gu, Seoul 08826, KoreaBiorobotics Laboratory, School of Mechanical and Aerospace Engineering, Seoul National University, Gwanak-ro 1, Gwanak-gu, Seoul 08826, KoreaThe size of a device and its adaptability to human properties are important factors in developing a wearable device. In wearable robot research, therefore, soft materials and tendon transmissions have been utilized to make robots compact and adaptable to the human body. However, when used for wearable robots, these methods sometimes cause uncertainties that originate from elongation of the soft material or from undefined human properties. In this research, to consider these uncertainties, we propose a data-driven method that identifies both kinematic and stiffness parameters using tension and wire stroke of the actuators. Through kinematic identification, a method is proposed to find the exact joint position as a function of the joint angle. Through stiffness identification, the relationship between the actuation force and the joint angle is obtained using Gaussian Process Regression (GPR). As a result, by applying the proposed method to a specific robot, the research outlined in this paper verifies how the proposed method can be used in wearable robot applications. This work examines a novel wearable robot named Exo-Index, which assists a human’s index finger through the use of three actuators. The proposed identification methods enable control of the wearable robot to result in appropriate postures for grasping objects of different shapes and sizes.https://www.mdpi.com/1424-8220/20/10/2852soft wearable robotrobotic systems parameter estimationjoint angle estimationdata-driven control
spellingShingle Byungchul Kim
Jiwon Ryu
Kyu-Jin Cho
Joint Angle Estimation of a Tendon-Driven Soft Wearable Robot through a Tension and Stroke Measurement
Sensors
soft wearable robot
robotic systems parameter estimation
joint angle estimation
data-driven control
title Joint Angle Estimation of a Tendon-Driven Soft Wearable Robot through a Tension and Stroke Measurement
title_full Joint Angle Estimation of a Tendon-Driven Soft Wearable Robot through a Tension and Stroke Measurement
title_fullStr Joint Angle Estimation of a Tendon-Driven Soft Wearable Robot through a Tension and Stroke Measurement
title_full_unstemmed Joint Angle Estimation of a Tendon-Driven Soft Wearable Robot through a Tension and Stroke Measurement
title_short Joint Angle Estimation of a Tendon-Driven Soft Wearable Robot through a Tension and Stroke Measurement
title_sort joint angle estimation of a tendon driven soft wearable robot through a tension and stroke measurement
topic soft wearable robot
robotic systems parameter estimation
joint angle estimation
data-driven control
url https://www.mdpi.com/1424-8220/20/10/2852
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AT jiwonryu jointangleestimationofatendondrivensoftwearablerobotthroughatensionandstrokemeasurement
AT kyujincho jointangleestimationofatendondrivensoftwearablerobotthroughatensionandstrokemeasurement