Comparison of Joint Angle Measurements from Three Types of Motion Capture Systems for Ergonomic Postural Assessment

Kim, Woojoo; Huang, Chunxi; Yun, Dong Hyeok; Saakes, Daniel; Xiong, Shuping

doi:10.1007/978-3-030-51549-2_1

Cited by 9 publications

(3 citation statements)

References 26 publications

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“…XSens MTw Awinda, an IMU-based MoCap system, was chosen as the reference system for this study because it has shown acceptable performance for ergonomic analysis (Kim et al, 2020). 11 inertial sensors were used to record joint angles from the upper part of the body as shown in Figure 2 One female and two male forklift operators participated in the study.…”

Section: Inertial Measurement Unit (Imu) System Setupmentioning

confidence: 99%

Evaluation of upper body postural assessment of forklift driving using a single depth camera

Elango

Petravic

Hanson

2022

Proceedings of the 7th International Digital Human Modeling Symposium -

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Observational postural assessment methods which are commonly used in industry are time consuming and have issues of inter-and intra-rater reliability. Computer vision (CV) based methods have been proposed, but they have mainly been tested inside lab environments. This study aims to develop and evaluate an upper body postural assessment system in a real industry environment using a single depth camera and OpenPose for the task of forklift driving. The results were compared with XSens, an Inertial Measurement Unit (IMU) based system. Data from three forklift drivers performing seven indoor and outdoor tasks were recorded with a depth camera and XSens sensors. The data were then analyzed with OpenPose with additional custom processing. The angles calculated by the computer vision system showed small errors compared to the XSens system and generally followed the trend of the XSens system joint angle values. However, the results after applying ergonomic thresholds were vastly different and the two systems rarely agreed. These findings suggest that the CV system needs further study to improve the robustness on self-occlusion and angle calculations. Also, XSens needs further study to assess its consistency and reliability in industrial environments.

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Section: Inertial Measurement Unit (Imu) System Setupmentioning

confidence: 99%

Evaluation of upper body postural assessment of forklift driving using a single depth camera

Elango

Petravic

Hanson

2022

Proceedings of the 7th International Digital Human Modeling Symposium -

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show abstract

“…XSens MTw Awinda, an IMU-based MoCap system, was chosen as the reference system for this study because it has shown acceptable performance for ergonomic analysis (Kim et al, 2020). One female and two male forklift operators participated in the study.…”

Section: Inertial Measurement Unit (Imu) System Setupmentioning

confidence: 99%

Proceedings of the 7th International Digital Human Modeling Symposium, Aug. 29-31, 2022, Iowa City, Iowa, USA

2022

Proceedings of the 7th International Digital Human Modeling Symposium -

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Digital human models are usually constructed to study the human anatomical or topological features and its variance and to optimize the size and shape of various products and tasks. Therefore, most of the researchers focussed on developing accurate three-dimensional digital human models based on surface mesh using various methods and techniques. However, such models do not allow biomechanical and ergonomic analyses of product interface materials that are in direct contact with the user. Based on manual testing using various materials and analysing the subjective response of users, researchers have shown that product interface material has an important impact on the overall product safety, comfort and even performance. Basic ergonomic and biomechanical guidelines regarding the material choice were provided based on the findings, however detailed material choice and even material parameter determination has not been studied, evaluated, and discussed due to the complex biomechanical systems and lack of appropriate digital human models.To overcome these limitations, numerical methods, especially the finite element method has been already used in the past by several authors. Finite element method allows calculating of various results in terms of internal stresses and contact pressure, deformations, and displacements, however it requires accurate development of numerical digital human models that accurately represent the anatomical, topological, material properties and boundary conditions.In this paper we present theoretical background and provide methodology for successful development of numerical digital human models that can be used for biomechanical analyses and product material ergonomic improvement. This is presented with a case study of the development of a numerical digital human finger model for ergonomic improvement of the biomechanical response of a product handle deformable interface material. Based on the developed numerical model, a novel deformable interface material is analysed that reduces the resulting contact pressure during grasping and provides more uniform pressure distribution while still providing sufficient stability.

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“…Thus, the accuracy of the joint angles depends not only on the spatial tracking performance of the trackers, but also on the calculation of the IK. The general study design is similar to that of [ 19 ], in which motion capture data from a depth camera and sensor suit were compared to a marker-based system on a joint angle basis. There is no comparable related work that evaluated the HTC Vive system combined with Final IK for joint angle measurements based on human movements.…”

Section: Related Workmentioning

confidence: 99%

An Evaluation of Motion Trackers with Virtual Reality Sensor Technology in Comparison to a Marker-Based Motion Capture System Based on Joint Angles for Ergonomic Risk Assessment

Vox

Weber

Wolf

et al. 2021

Sensors

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The reproduction and simulation of workplaces, and the analysis of body postures during work processes, are parts of ergonomic risk assessments. A commercial virtual reality (VR) system offers the possibility to model complex work scenarios as virtual mock-ups and to evaluate their ergonomic designs by analyzing motion behavior while performing work processes. In this study a VR tracking sensor system (HTC Vive tracker) combined with an inverse kinematic model (Final IK) was compared with a marker-based optical motion capture system (Qualisys). Marker-based optical motion capture systems are considered the gold standard for motion analysis. Therefore, Qualisys was used as the ground truth in this study. The research question to be answered was how accurately the HTC Vive System combined with Final IK can measure joint angles used for ergonomic evaluation. Twenty-six subjects were observed simultaneously with both tracking systems while performing 20 defined movements. Sixteen joint angles were analyzed. Joint angle deviations between ±6∘ and ±42∘ were identified. These high deviations must be considered in ergonomic risk assessments when using a VR system. The results show that commercial low-budget tracking systems have the potential to map joint angles. Nevertheless, substantial weaknesses and inaccuracies in some body regions must be taken into account. Recommendations are provided to improve tracking accuracy and avoid systematic errors.

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Comparison of Joint Angle Measurements from Three Types of Motion Capture Systems for Ergonomic Postural Assessment

Cited by 9 publications

References 26 publications

Evaluation of upper body postural assessment of forklift driving using a single depth camera

Evaluation of upper body postural assessment of forklift driving using a single depth camera

Proceedings of the 7th International Digital Human Modeling Symposium, Aug. 29-31, 2022, Iowa City, Iowa, USA

An Evaluation of Motion Trackers with Virtual Reality Sensor Technology in Comparison to a Marker-Based Motion Capture System Based on Joint Angles for Ergonomic Risk Assessment

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