Human body finite element (FE) models can be used for seating comfort assessment by providing biomechanical related parameters such as internal loads and soft-tissue deformations. However, most of the published models were only validated under a condition far from a real seating situation. Their ability to be repositioned may also be limited. In recent years, an open-source PIPER software package has been developed to help personalize and position Human Body Models (HBMs) for crash simulation. We have morphed the PIPER Child model into an adult FE model. In this paper, we present how the initially morphed adult FE model was adapted for assessing seating comfort and validated for different seating conditions. Experimental data was collected using a reconfigurable experimental seat and pressure mats. Four seat configurations were defined with the seat pan angle (SPA) from 0° to 15° (5° in steps) and seat pan to seat backrest angle (SP2BA) kept to 100°. Simulated results in terms of seat contact area (ContactA), peak pressure (PeakP), mean pressure (MeanP), and pressure profiles showed good agreement with experimental observations. The full-body FE model developed and validated in this work will be used as a reference for further development of scalable and positionable models using the PIPER software framework. The model will be open source to facilitate reuse and further improvements.
{"title":"Developing a full-body finite element model and its preliminary validation for seating comfort","authors":"S. Liu, P. Beillas, Li Ding, Xuguang Wang","doi":"10.17077/dhm.31775","DOIUrl":"https://doi.org/10.17077/dhm.31775","url":null,"abstract":"Human body finite element (FE) models can be used for seating comfort assessment by providing biomechanical related parameters such as internal loads and soft-tissue deformations. However, most of the published models were only validated under a condition far from a real seating situation. Their ability to be repositioned may also be limited. In recent years, an open-source PIPER software package has been developed to help personalize and position Human Body Models (HBMs) for crash simulation. We have morphed the PIPER Child model into an adult FE model. In this paper, we present how the initially morphed adult FE model was adapted for assessing seating comfort and validated for different seating conditions. Experimental data was collected using a reconfigurable experimental seat and pressure mats. Four seat configurations were defined with the seat pan angle (SPA) from 0° to 15° (5° in steps) and seat pan to seat backrest angle (SP2BA) kept to 100°. Simulated results in terms of seat contact area (ContactA), peak pressure (PeakP), mean pressure (MeanP), and pressure profiles showed good agreement with experimental observations. The full-body FE model developed and validated in this work will be used as a reference for further development of scalable and positionable models using the PIPER software framework. The model will be open source to facilitate reuse and further improvements.","PeriodicalId":111717,"journal":{"name":"Proceedings of the 7th International Digital Human Modeling Symposium (DHM 2022) and Iowa Virtual Human Summit 2022 -","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129823525","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
E. Brolin, Niclas Delfs, Martin Rebas, T. Karlsson, L. Hanson, D. Högberg
This paper presents the development of body shape data based digital human models, i.e. manikins, for ergonomics simulations. In Digital human modelling (DHM) tools it is important that the generated manikin models are accurate and representative for different body sizes and shapes as well as being able to scale and move during motion simulations. The developed DHM models described in this paper are based on body scan data from the CAESAR anthropometric survey. The described development process consists of six steps and includes alignment of body scans, fitting of template mesh through homologous body modelling, statistical prediction of body shape, joint centre prediction, adjustment of posture to T-pose and finally generation of relation between predicted mesh and manikin mesh. The implemented method can be used to create any type of manikin size that directly can be used in a simulation. To evaluate the results a comparison was done of original body scans and statistically predicted meshes generated in an intermediary step as well as the resulting DHM manikins. The accuracy of the statistically predicted meshes are relatively good even though differences can be seen, mostly related to postural differences and differences around smaller areas with distinct shapes. The biggest differences between the final manikin models and the original scans can be found in the shoulder and abdominal area, in addition to the significantly different initial posture that the manikin models have. To further improve and evaluate the generated manikin models additional body scan data sets that includes more diverse postures would be useful. DHM tool functionality could also be improved to enable evaluation of the accuracy of the generated manikin models, possibly resulting in DHM tools more compliant with standard documents. At the same time standard documents might need to be updated in some aspects to include more three-dimensional accuracy analysis.
{"title":"Development of body shape data based digital human models for ergonomics simulations","authors":"E. Brolin, Niclas Delfs, Martin Rebas, T. Karlsson, L. Hanson, D. Högberg","doi":"10.17077/dhm.31759","DOIUrl":"https://doi.org/10.17077/dhm.31759","url":null,"abstract":"This paper presents the development of body shape data based digital human models, i.e. manikins, for ergonomics simulations. In Digital human modelling (DHM) tools it is important that the generated manikin models are accurate and representative for different body sizes and shapes as well as being able to scale and move during motion simulations. The developed DHM models described in this paper are based on body scan data from the CAESAR anthropometric survey. The described development process consists of six steps and includes alignment of body scans, fitting of template mesh through homologous body modelling, statistical prediction of body shape, joint centre prediction, adjustment of posture to T-pose and finally generation of relation between predicted mesh and manikin mesh. The implemented method can be used to create any type of manikin size that directly can be used in a simulation. To evaluate the results a comparison was done of original body scans and statistically predicted meshes generated in an intermediary step as well as the resulting DHM manikins. The accuracy of the statistically predicted meshes are relatively good even though differences can be seen, mostly related to postural differences and differences around smaller areas with distinct shapes. The biggest differences between the final manikin models and the original scans can be found in the shoulder and abdominal area, in addition to the significantly different initial posture that the manikin models have. To further improve and evaluate the generated manikin models additional body scan data sets that includes more diverse postures would be useful. DHM tool functionality could also be improved to enable evaluation of the accuracy of the generated manikin models, possibly resulting in DHM tools more compliant with standard documents. At the same time standard documents might need to be updated in some aspects to include more three-dimensional accuracy analysis.","PeriodicalId":111717,"journal":{"name":"Proceedings of the 7th International Digital Human Modeling Symposium (DHM 2022) and Iowa Virtual Human Summit 2022 -","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124092932","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ritwik Rakshit, Shuvrodeb Barman, Y. Xiang, Jie Yang
{"title":"Joint velocity dependence of fatigue in isokinetic tasks","authors":"Ritwik Rakshit, Shuvrodeb Barman, Y. Xiang, Jie Yang","doi":"10.17077/dhm.31764","DOIUrl":"https://doi.org/10.17077/dhm.31764","url":null,"abstract":"","PeriodicalId":111717,"journal":{"name":"Proceedings of the 7th International Digital Human Modeling Symposium (DHM 2022) and Iowa Virtual Human Summit 2022 -","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125749256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The need for nimble, eco-friendly transportation solutions in metropolitan areas continues to rise. To meet this need companies have begun to design and manufacture small profile, high payload, electric scooters. Yet, balancing the claim space requirements for payload, mechanical systems, and the battery pack while also maintaining effective occupant packaging considerations is a challenge. The claim space required for a battery that can sustain a sufficient driving range (>150km) directly influences the shape and size of the rear chassis. However, the size and shape of the rear chassis also influences the potential for an occupant’s heel and calf to catch under the rear chassis when raising or lowering a foot for balance during common vehicle maneuvers. The aim of this analysis was to identify possible collision points between the heel or calf of a 50th and 95th percentile male stature occupant and the rear chassis when lowering a foot towards the ground when the scooter was in upright and tilted by 30° positions (turning). Santos Pro™ (SantosHuman Inc., Coralville, IA) was used to model the required occupant behaviors. The Zone Differentiation tool then generated a range of motion volume map for the calf and heel assuming a seated occupant posture. The volume map was overlaid on the geometry to assist the engineering team in visualizing possible collision points for each avatar. The engineering team was able to revise the geometry for the rear chassis to reduce overlaps with the heel and calf volume map, while also maintaining minimum claim space needs for the battery pack. The improved rear chassis design was then imported into the Santos Pro™ software to visualize and verify the reduction of potential collision locations. Santos Pro™ provided a time-efficient design-on-the-fly method to understand the potential severity of, and to correct, a heel and calf clearance concern within early-stage CAE. By evaluating the clearance concern proactively, the problem was quantified and solved within days, prior to costly physical prototyping and human testing.
{"title":"Using Santos Pro™ trade-off analysis to inform the rear chassis design of a novel electric scooter","authors":"S. Fischer, J. Davidson, Sanjay Veerasammy","doi":"10.17077/dhm.31743","DOIUrl":"https://doi.org/10.17077/dhm.31743","url":null,"abstract":"The need for nimble, eco-friendly transportation solutions in metropolitan areas continues to rise. To meet this need companies have begun to design and manufacture small profile, high payload, electric scooters. Yet, balancing the claim space requirements for payload, mechanical systems, and the battery pack while also maintaining effective occupant packaging considerations is a challenge. The claim space required for a battery that can sustain a sufficient driving range (>150km) directly influences the shape and size of the rear chassis. However, the size and shape of the rear chassis also influences the potential for an occupant’s heel and calf to catch under the rear chassis when raising or lowering a foot for balance during common vehicle maneuvers. The aim of this analysis was to identify possible collision points between the heel or calf of a 50th and 95th percentile male stature occupant and the rear chassis when lowering a foot towards the ground when the scooter was in upright and tilted by 30° positions (turning). Santos Pro™ (SantosHuman Inc., Coralville, IA) was used to model the required occupant behaviors. The Zone Differentiation tool then generated a range of motion volume map for the calf and heel assuming a seated occupant posture. The volume map was overlaid on the geometry to assist the engineering team in visualizing possible collision points for each avatar. The engineering team was able to revise the geometry for the rear chassis to reduce overlaps with the heel and calf volume map, while also maintaining minimum claim space needs for the battery pack. The improved rear chassis design was then imported into the Santos Pro™ software to visualize and verify the reduction of potential collision locations. Santos Pro™ provided a time-efficient design-on-the-fly method to understand the potential severity of, and to correct, a heel and calf clearance concern within early-stage CAE. By evaluating the clearance concern proactively, the problem was quantified and solved within days, prior to costly physical prototyping and human testing.","PeriodicalId":111717,"journal":{"name":"Proceedings of the 7th International Digital Human Modeling Symposium (DHM 2022) and Iowa Virtual Human Summit 2022 -","volume":"82 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122423700","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Weighted vest (WV) use has been explored as a modifier of jumping and landing performance in athletes, but it is unclear whether performance is modified with different WV loading arrangements. The purposes of this study were to a) examine the effects of different external load arrangements on vertical jump height and lower-extremity biomechanics during a countermovement jump and b) understand the effects on men versus women. A scaled musculoskeletal gait model in OpenSim was used with sagittal plane inverse kinematics procedures for 24 participants (75.71 ± 18.88 Kg; 1.71 ± 0.09 m) equally divided between men and women performing jump-landing in four weighted vest loading conditions (back-loaded, front-loaded, split-loaded, unloaded). Mixed-model factorial analyses of variance (α=0.05) and effect sizes (ES) were used to identify and quantify differences between sexes and loading conditions. Regardless of loading conditions, men showed greater jump height (p<0.001, ES=2.22) and greater hip (p<0.001, ES=1.59), and knee (p=0.026, ES=0.90) moments. No significant difference in the hip (p=0.478, ES=0.30) or knee (p=0.580, ES=0.23) angular displacement was observed between men and women. Without considering sex, the unloaded condition showed greater jump height (p<0.001, ES=0.4), hip displacement (p=0.006, ES=0.34), and hip (p=0.019, ES=0.36), and knee (p=0.004, ES=0.48) moments when compared to the back-loaded condition. Jump height (p=0.04, ES=0.1) and hip moments (p=0.028, ES=0.36) were also greater for the split-loaded compared to the back-loaded condition. Both the unloaded and split-loaded conditions showed greater jump height (p<0.001, ES=0.4; p<0.001, ES=0.3) and hip moments (p<0.001, ES=0.55; p=0.003, ES=0.35) compared with the front-loaded condition. A significantly greater magnitude of the hip displacement was detected for the split loaded condition compared to the front-loaded condition (p<0.001, ES=0.19). These results indicate that different external loading arrangements significantly affect the biomechanical performance output and differences in the load accommodation strategies between men and women during the period between the weighting and propulsion phases of jumping.
{"title":"Effects of sex and weighted vest load arrangements on lower biomechanics and jump height during countermovement jump","authors":"Juan Baus, J. Harry, James Yang","doi":"10.17077/dhm.31763","DOIUrl":"https://doi.org/10.17077/dhm.31763","url":null,"abstract":"Weighted vest (WV) use has been explored as a modifier of jumping and landing performance in athletes, but it is unclear whether performance is modified with different WV loading arrangements. The purposes of this study were to a) examine the effects of different external load arrangements on vertical jump height and lower-extremity biomechanics during a countermovement jump and b) understand the effects on men versus women. A scaled musculoskeletal gait model in OpenSim was used with sagittal plane inverse kinematics procedures for 24 participants (75.71 ± 18.88 Kg; 1.71 ± 0.09 m) equally divided between men and women performing jump-landing in four weighted vest loading conditions (back-loaded, front-loaded, split-loaded, unloaded). Mixed-model factorial analyses of variance (α=0.05) and effect sizes (ES) were used to identify and quantify differences between sexes and loading conditions. Regardless of loading conditions, men showed greater jump height (p<0.001, ES=2.22) and greater hip (p<0.001, ES=1.59), and knee (p=0.026, ES=0.90) moments. No significant difference in the hip (p=0.478, ES=0.30) or knee (p=0.580, ES=0.23) angular displacement was observed between men and women. Without considering sex, the unloaded condition showed greater jump height (p<0.001, ES=0.4), hip displacement (p=0.006, ES=0.34), and hip (p=0.019, ES=0.36), and knee (p=0.004, ES=0.48) moments when compared to the back-loaded condition. Jump height (p=0.04, ES=0.1) and hip moments (p=0.028, ES=0.36) were also greater for the split-loaded compared to the back-loaded condition. Both the unloaded and split-loaded conditions showed greater jump height (p<0.001, ES=0.4; p<0.001, ES=0.3) and hip moments (p<0.001, ES=0.55; p=0.003, ES=0.35) compared with the front-loaded condition. A significantly greater magnitude of the hip displacement was detected for the split loaded condition compared to the front-loaded condition (p<0.001, ES=0.19). These results indicate that different external loading arrangements significantly affect the biomechanical performance output and differences in the load accommodation strategies between men and women during the period between the weighting and propulsion phases of jumping.","PeriodicalId":111717,"journal":{"name":"Proceedings of the 7th International Digital Human Modeling Symposium (DHM 2022) and Iowa Virtual Human Summit 2022 -","volume":"97 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131401186","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Lamb, Seunghun Lee, E. Billing, D. Högberg, James Yang
Posture/motion prediction is the basis of the human motion simulations that make up the core of many digital human modeling (DHM) tools and methods. With the goal of producing realistic postures and motions, a common element of posture/motion prediction methods involves applying some set of constraints to biomechanical models of humans on the positions and orientations of specified body parts. While many formulations of biomechanical constraints may produce valid predictions, they must overcome the challenges posed by the highly redundant nature of human biomechanical systems. DHM researchers and developers typically focus on optimization formulations to facilitate the identification and selection of valid solutions. While these approaches produce optimal behavior according to some, e.g., ergonomic, optimization criteria, these solutions require considerable computational power and appear vastly different from how humans produce motion. In this paper, we take a different approach and consider the Forward and Backward Reaching Inverse Kinematics (FABRIK) solver developed in the context of computer graphics for rigged character animation. This approach identifies postures quickly and efficiently, often requiring a fraction of the computation time involved in optimization-based methods. Critically, the FABRIK solver identifies posture predictions based on a lightweight heuristic approach. Specifically, the solver works in joint position space and identifies solutions according to a minimal joint displacement principle. We apply the FABRIK solver to a 7-degree of freedom human arm model during a reaching task from an initial to an end target location, fixing the shoulder position and providing the end effector (index fingertip) position and orientation from each frame of the motion capture data. In this preliminary study, predicted postures are compared to experimental data from a single human subject. Overall the predicted postures were very near the recorded data, with an average RMSE of 1.67°. Although more validation is necessary, we believe that the FABRIK solver has great potential for producing realistic human posture/motion in real-time, with applications in the area of DHM.
{"title":"Forward and Backwards Reaching Inverse Kinematics (FABRIK) solver for DHM: A pilot study","authors":"M. Lamb, Seunghun Lee, E. Billing, D. Högberg, James Yang","doi":"10.17077/dhm.31772","DOIUrl":"https://doi.org/10.17077/dhm.31772","url":null,"abstract":"Posture/motion prediction is the basis of the human motion simulations that make up the core of many digital human modeling (DHM) tools and methods. With the goal of producing realistic postures and motions, a common element of posture/motion prediction methods involves applying some set of constraints to biomechanical models of humans on the positions and orientations of specified body parts. While many formulations of biomechanical constraints may produce valid predictions, they must overcome the challenges posed by the highly redundant nature of human biomechanical systems. DHM researchers and developers typically focus on optimization formulations to facilitate the identification and selection of valid solutions. While these approaches produce optimal behavior according to some, e.g., ergonomic, optimization criteria, these solutions require considerable computational power and appear vastly different from how humans produce motion. In this paper, we take a different approach and consider the Forward and Backward Reaching Inverse Kinematics (FABRIK) solver developed in the context of computer graphics for rigged character animation. This approach identifies postures quickly and efficiently, often requiring a fraction of the computation time involved in optimization-based methods. Critically, the FABRIK solver identifies posture predictions based on a lightweight heuristic approach. Specifically, the solver works in joint position space and identifies solutions according to a minimal joint displacement principle. We apply the FABRIK solver to a 7-degree of freedom human arm model during a reaching task from an initial to an end target location, fixing the shoulder position and providing the end effector (index fingertip) position and orientation from each frame of the motion capture data. In this preliminary study, predicted postures are compared to experimental data from a single human subject. Overall the predicted postures were very near the recorded data, with an average RMSE of 1.67°. Although more validation is necessary, we believe that the FABRIK solver has great potential for producing realistic human posture/motion in real-time, with applications in the area of DHM.","PeriodicalId":111717,"journal":{"name":"Proceedings of the 7th International Digital Human Modeling Symposium (DHM 2022) and Iowa Virtual Human Summit 2022 -","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114785361","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In order to assemble a part (of e.g., an engine), a human hand must obtain complete control of its motion through application of forces and toques at multiple contact points. Today, it is often time-consuming to synthesize a good hand grasp of a part using Digital Human Modeling (DHM) tools because these tools require detailed manual inputs from a user such as manually placing a digital hand around a feasible grasp location and then closing the fingers around the part. In a previous paper, we presented two different methods (i.e., Pointwise Shortest Distance and Environment Clearance) to color part surfaces by taking environmental distance constraints into account so that a user such as an assembly simulation expert can easily identify feasible grasp locations. Due to the robustness of the implementation, even triangle meshes with common geometric flaws such as cracks and gaps can be handled. In this paper, we leverage on this feasibility analysis and present a user-guided grasp planning approach that significantly speeds up the grasp modeling process. First, the user selects a predefined grip type and then sets an approach direction for the hand. To synthesize many grasps, we randomly sample the hand’s rotation around the approach direction. Next, the hand is moved towards the part until the hand’s Grasp Center Point (GCP) reaches the geometry of the part or a collision between the hand and the part is detected. If a collision was detected, we move the hand backwards until there is no collision between the hand and the part anymore. Finally, we close the hand’s fingers around the part to synthesize a grasp. In this way, we can quickly synthesize a multitude of grasps and let the user choose among the ones with the best grasp qualities, where each grasp quality is computed using the corresponding 6D grasp wrench hull. We believe that this user-guided grasp planning approach can significantly enhance DHM tools such as Intelligently Moving Manikins (IMMA) when it comes to user usability.
{"title":"User-guided grasp planning for digital hand","authors":"Yi Li, Niclas Delfs, J. Carlson","doi":"10.17077/dhm.31767","DOIUrl":"https://doi.org/10.17077/dhm.31767","url":null,"abstract":"In order to assemble a part (of e.g., an engine), a human hand must obtain complete control of its motion through application of forces and toques at multiple contact points. Today, it is often time-consuming to synthesize a good hand grasp of a part using Digital Human Modeling (DHM) tools because these tools require detailed manual inputs from a user such as manually placing a digital hand around a feasible grasp location and then closing the fingers around the part. In a previous paper, we presented two different methods (i.e., Pointwise Shortest Distance and Environment Clearance) to color part surfaces by taking environmental distance constraints into account so that a user such as an assembly simulation expert can easily identify feasible grasp locations. Due to the robustness of the implementation, even triangle meshes with common geometric flaws such as cracks and gaps can be handled. In this paper, we leverage on this feasibility analysis and present a user-guided grasp planning approach that significantly speeds up the grasp modeling process. First, the user selects a predefined grip type and then sets an approach direction for the hand. To synthesize many grasps, we randomly sample the hand’s rotation around the approach direction. Next, the hand is moved towards the part until the hand’s Grasp Center Point (GCP) reaches the geometry of the part or a collision between the hand and the part is detected. If a collision was detected, we move the hand backwards until there is no collision between the hand and the part anymore. Finally, we close the hand’s fingers around the part to synthesize a grasp. In this way, we can quickly synthesize a multitude of grasps and let the user choose among the ones with the best grasp qualities, where each grasp quality is computed using the corresponding 6D grasp wrench hull. We believe that this user-guided grasp planning approach can significantly enhance DHM tools such as Intelligently Moving Manikins (IMMA) when it comes to user usability.","PeriodicalId":111717,"journal":{"name":"Proceedings of the 7th International Digital Human Modeling Symposium (DHM 2022) and Iowa Virtual Human Summit 2022 -","volume":"66 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127107142","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
When rotational acceleration occurs in the body, the endolymph moves with velocity owing to rotational inertia, and the cupula is tilted by the force generated by the endolymph. When the cupula is tilted, hair cells are also tilted to create a sense of rotation. At the same time, a rotational signal is transmitted, and if the signal does not match the field of sight, various symptoms such as dizziness, nausea, and headache appear. To resolve the discrepancy between the rotational signal and the sight caused by the tilt of hair cells such as motion sickness, in this study, we developed a vestibular finite element (FE) simulation model to control the angle of hair cells in the cupula. The simulation model consisted of a straight (linear) model and a model identical to the actual shape (curved) model. A fluid velocity of around 0.2 Hz, which is associated with motion sickness, was applied to the model to bend the cupula. [1] A magnetic field was applied by positioning the coil along the three axes based on the cupula and a current is passed to generate a Lorentz force. By increasing or decreasing the current, the displacement moved by the cupula according to the magnetic field was measured. As a result, in both models, the displacement of the cupula tends to decrease when the current is increased.
{"title":"The study of endolymph flow and hair cell control analysis simulation model through electromagnetic fields","authors":"Hyeyeong Song, Soon-Hyuck Jung, Junghwa Hong","doi":"10.17077/dhm.31788","DOIUrl":"https://doi.org/10.17077/dhm.31788","url":null,"abstract":"When rotational acceleration occurs in the body, the endolymph moves with velocity owing to rotational inertia, and the cupula is tilted by the force generated by the endolymph. When the cupula is tilted, hair cells are also tilted to create a sense of rotation. At the same time, a rotational signal is transmitted, and if the signal does not match the field of sight, various symptoms such as dizziness, nausea, and headache appear. To resolve the discrepancy between the rotational signal and the sight caused by the tilt of hair cells such as motion sickness, in this study, we developed a vestibular finite element (FE) simulation model to control the angle of hair cells in the cupula. The simulation model consisted of a straight (linear) model and a model identical to the actual shape (curved) model. A fluid velocity of around 0.2 Hz, which is associated with motion sickness, was applied to the model to bend the cupula. [1] A magnetic field was applied by positioning the coil along the three axes based on the cupula and a current is passed to generate a Lorentz force. By increasing or decreasing the current, the displacement moved by the cupula according to the magnetic field was measured. As a result, in both models, the displacement of the cupula tends to decrease when the current is increased.","PeriodicalId":111717,"journal":{"name":"Proceedings of the 7th International Digital Human Modeling Symposium (DHM 2022) and Iowa Virtual Human Summit 2022 -","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126705071","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper presents an early-design methodology to quantify vision obstruction caused by halo-type cockpit safety equipment introduced into Formula One (F1) racing in 2018. The halo is a curved bar that surrounds the driver's head over the cockpit opening and offers additional protection to drivers. However, the halo's introduction has raised concerns over vision obstruction-related issues due to its vertical and horizontal bars (pillar-like elements) sitting in front of the cockpit. This study assesses vision obstructions by exploring the driver's forward field of view (FoV) based on the coverage zone analysis. This research utilizes digital manikins inserted in a digital F1 racecar mockup to assess the effects of halo concept variants on vision obstruction. The preliminary results showed that the vision obstruction was not only affected by the halo geometry and size but also the orientation of the F1 car in different racetrack segments. The methodology discussed in this study is critical for other early-stage product design and development challenges, where designers demand "quick-and-dirty" ergonomics evaluation of vision obstruction before building time-consuming and costly physical mockups.
{"title":"Quantifying vision obstruction of Formula One (F1) halo concept variants","authors":"H. Demirel, S. Srinivasan","doi":"10.17077/dhm.31755","DOIUrl":"https://doi.org/10.17077/dhm.31755","url":null,"abstract":"This paper presents an early-design methodology to quantify vision obstruction caused by halo-type cockpit safety equipment introduced into Formula One (F1) racing in 2018. The halo is a curved bar that surrounds the driver's head over the cockpit opening and offers additional protection to drivers. However, the halo's introduction has raised concerns over vision obstruction-related issues due to its vertical and horizontal bars (pillar-like elements) sitting in front of the cockpit. This study assesses vision obstructions by exploring the driver's forward field of view (FoV) based on the coverage zone analysis. This research utilizes digital manikins inserted in a digital F1 racecar mockup to assess the effects of halo concept variants on vision obstruction. The preliminary results showed that the vision obstruction was not only affected by the halo geometry and size but also the orientation of the F1 car in different racetrack segments. The methodology discussed in this study is critical for other early-stage product design and development challenges, where designers demand \"quick-and-dirty\" ergonomics evaluation of vision obstruction before building time-consuming and costly physical mockups.","PeriodicalId":111717,"journal":{"name":"Proceedings of the 7th International Digital Human Modeling Symposium (DHM 2022) and Iowa Virtual Human Summit 2022 -","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132984174","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
L. Frey-Law, R. Bhatt, Russell T. Schneider, Guillermo Laguna Mosqueda, Marco Tena Salais, Landon Evans, K. Abdel-Malek
The US Army has developed a battery of physical fitness test events to measure soldier readiness to engage with and overmatch the enemy in close combat. The original Army Physical Fitness Test (APFT) only assessed three events: a two-mile run, push-ups, and sit-ups. To better represent the myriad of physical tasks soldiers are exposed to and expected to complete, a new Army Combat Fitness Test (ACFT) was developed (US Army, 2018). The ACFT comprises six physical exercise tasks: (a) threerepetition maximum deadlift; (b) standing power throw; (c) hand-release push-ups; (d) a combination sprint, drag, and carry task; (e) leg tuck (or plank); and (f) two-mile run. The Army performed several investigations comparing task performance of the ACFT to a simulated battle drills and common soldier tasks (CSTs) obstacle course, where completion time was the primary outcome measure. However, the Army was not able to compare more detailed aspects between CSTs and the new ACFT, such as biomechanical analyses based on digital human modeling.
{"title":"Modeling ability to perform common soldier tasks based on the Army Combat Fitness Test dead lift","authors":"L. Frey-Law, R. Bhatt, Russell T. Schneider, Guillermo Laguna Mosqueda, Marco Tena Salais, Landon Evans, K. Abdel-Malek","doi":"10.17077/dhm.31784","DOIUrl":"https://doi.org/10.17077/dhm.31784","url":null,"abstract":"The US Army has developed a battery of physical fitness test events to measure soldier readiness to engage with and overmatch the enemy in close combat. The original Army Physical Fitness Test (APFT) only assessed three events: a two-mile run, push-ups, and sit-ups. To better represent the myriad of physical tasks soldiers are exposed to and expected to complete, a new Army Combat Fitness Test (ACFT) was developed (US Army, 2018). The ACFT comprises six physical exercise tasks: (a) threerepetition maximum deadlift; (b) standing power throw; (c) hand-release push-ups; (d) a combination sprint, drag, and carry task; (e) leg tuck (or plank); and (f) two-mile run. The Army performed several investigations comparing task performance of the ACFT to a simulated battle drills and common soldier tasks (CSTs) obstacle course, where completion time was the primary outcome measure. However, the Army was not able to compare more detailed aspects between CSTs and the new ACFT, such as biomechanical analyses based on digital human modeling.","PeriodicalId":111717,"journal":{"name":"Proceedings of the 7th International Digital Human Modeling Symposium (DHM 2022) and Iowa Virtual Human Summit 2022 -","volume":"123 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133112183","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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