AHFE Open AccessDigital Human Modeling and Applied Optimization
Editors: Sofia Scataglini, Sudhakar Rajulu
Topics: Digital Human Modeling and Applied Optimization
Publication Date: 2022
ISBN: 978-1-958651-22-3
DOI: 10.54941/ahfe1001892
Articles
Three-dimensional Scalp Shape Prediction from Face and Neck Shapes
The scalp shape is one of the critical factors determining the proper fit for personalized helmets and other head-borne products. Three-dimensional (3D) surface scanning technology enables accurate capture of the 3D shape of an individual’s face, but most head scans do not capture the scalp shape due to hair artifacts because the typical scanning systems do not penetrate through hair. Most head shape studies use an elastic cap that compresses hair, but this does not entirely remove the effects of hair on the head surface shape. Consequently, a method to estimate scalp shape with conventional scanning would be valuable.Objective: This paper presents a model-based approach to predict the 3D scalp geometry from the rest of the head shape, i.e., face and neck, and validates the proposed method.Method: A statistical head shape model (http://humanshape.org/head/) based on 180 ethnically diverse female and male bald head scans was used in this study. A method was developed to predict scalp shapes by fitting the face and neck part of the model to target scans in the model’s shape space defined by 100 principal components. Results: New data from 81 male and female bald head scans not used in the original statistical model development were tested to validate the proposed approach. The prediction results without any information about the scalp shape showed that the mean absolute error at node locations was 2.3 mm on average, and the 95th-percentile absolute error was 6.2 mm across the test scans. When five landmark points digitized on the scalp surface were added in the fitting process, the mean absolute error was reduced to 1.7 mm with the average 95th-percentile of 4.6 mm.Discussion: Given that bald head scans are not generally available, the new method provides a useful and practical solution for obtaining scalp surface information from generic head scans for designing headgear products. The results showed that the scalp shape can be effectively predicted from face and neck shape, and the predictions can be improved through minimal information of the scalp, e.g., a few scalp landmarks or head dimensions. The major limitation of the proposed method is that errors will be larger for the scans with unusual face and neck poses. Another limitation is that although the model we used is based on an anthropometrically diverse population, more work is needed to assess the quality of the predictions for markedly different populations.
Daniel Park, Matthew Reed
Open Access
Article
Conference Proceedings
Demonstrating the Value of 3D Models to Support Large-Scale Digital Modifications at Nuclear Power Plants
The existing nuclear power plants (NPPs) in the United States (U.S.) are important for creating safe and reliable carbon free electricity for now and in the future. Many NPPs are currently in the process of extending their operating licenses for continued generation. Extending the lifespan of these plants provide an opportunity to modernize their operating model by introducing new technologies that reduce operations and maintenance costs. Many businesses have introduced new technologies to help with reducing costs; however, introduction of new technology has created situations where processes were less efficient. Hence, human factors evaluations are needed to help ensure that new technologies can integrate safely and reliably with current operations. Standards and guidelines for applying human factors in NPP modernization are available from the Nuclear Regulatory Commission, (NRC) , the Electric Power Research Institute (EPRI), Institute of Nuclear Power Operations (INPO), among others. One such method used in human factors to support modernization is the use of three-dimensional (3D) modeling that enables visualization and anthropometric evaluation. That is, anthropometric data including reach, sight, and distance are important human factors considerations to ensure that all interactions can be completed safely and effectively by personnel interacting with work processes and operations.This report discusses the importance of applying 3D modeling techniques within the context of human factors evaluation for large scale digital NPP modifications. 3D modeling is one area where human factors engineering can be applied when modifying or adding new technology into control room operations. Models of the control room can be created in 3D modeling tools to present visualizations of modifications or new technologies being introduced into the control room. Available software tools such as Trimble Sketchup and Control Room Engineering Advanced Toolkit Environment (CREATE) (developed by the Institute for Energy Technology) can be used to evaluate anthropometric considerations like sight lines, readability, distance of controls, and other related information to represent changes prior to implementing new modifications or technologies in a control room. These tools enable early human factors input that can drive effective decisions making later in the development process. The CREATE tool has been designed to include guidance and information from the NRC (i.e., NUREG-0700) directly into its operating system allowing for human factors guidance to be automatically applied when creating 3D visualization of a control room. 3D modeling can also be used as a visualization tool to describe and report changes to key stakeholders very early on, prior to implementing changes in a control room. This report will summarize recent work performed in collaboration with a partnering utility that generates lessons learned when using 3D modeling for control room modernization.
Jeremy Mohon, Casey Kovesdi
Open Access
Article
Conference Proceedings
A Proactive Ergonomics Framework to Assess A-Pillar Vision Obstruction
Many automobile accidents involving pedestrians in city driving at roundabouts, intersections, and crossings are related to blind spots caused by A-pillars—vertical posts that straddle the windshield and tie the car's body to the roof. Designers have addressed such problems by changing A-pillars' geometry to improve drivers' forward field of view (FoV). Other high-tech solutions include implementing cameras with integrated displays and proximity sensors to enhance drivers' situational awareness. However, these solutions can be expensive and still do not significantly improve the obstruction caused by the A-pillar. There is a need for assessing concept variants and alternate solutions during preliminary design to assess A-pillar vision obstruction. This paper proposes a proof-of-concept proactive ergonomics framework that integrates generative design (GD) and digital human modeling (DHM) to quantify A-pillar obstruction. Overall, this research demonstrates how the proposed framework provides a rapid and rough ergonomics strategy by enabling designers to assess design attributes early in design proactively. We utilized the proposed framework in a generic case study that compares the concept pillar designs and current conventional pillars regarding their performance in reducing vision obstructions.
Onan Demirel, Srinam Srinivasan
Open Access
Article
Conference Proceedings
Methodology Based on 3D Thermal Scanner and AI Integration to Model Thermal Comfort and Ergonomics.
The current pandemic situation due to the appearance of the coronavirus-2 or SARS-CoV-2 (COVID-19) has increased the demand and familiarization of the population with infrared cameras and their thermal interpretation. Infrared radiation and the technology behind it have become a necessity not only developing new applications for the present but also for the future. In the post-pandemic world, commercial solutions to existing problems are being developed with this technology and with very efficient approaches, reducing costs and complementing many areas.Institute of Biomechanics of Valencia (IBV) is constantly innovating in the field of infrared thermal imaging and its applications in the well-being of people through research, experimentation and user validation. 3D models have been developed merging anthropometric data and thermal information based on scanners, 3D reconstruction and imagen processing. Some of the algorithms for monitoring and reconstruction system are based on a FLIR A35 thermal camera and an INTEL RealSense D455 depth sensor, a low-cost, high-performance sensor.Artificial intelligence techniques applied to images, mainly in visible or RGB datasets, have undergone significant development in recent years, however there is a gap in the application in thermal images. The IBV has compiled a powerful database for years from many users, insulation in clothes, extreme scenarios and different poses and face orientations. Many networks, models and libraries of computer vision, have been explored and some AI techniques (machine and deep learning) have been applied to extract information from those images, although open solutions and networks do not work accurately. The thermal database has been used to retrain these network models and the results have been considerably better.Near real-time, low-cost 3D thermal reconstruction, with embedded AI techniques, has been applied in facemasks evaluation, face recognition, feature and key points extraction, segmentation and development of automatic thermal measure algorithms. From feature extraction and landmark information, aspects such as thermotype, age and sex, have been also determined, or even the effects of the emotions, rotations or artifacts like glasses, facemasks or beards on the identification of the user. IBV has a huge background in this technology and develops new innovative solutions in order to tackle with new challenges, from determining the effect a facemask has, in thermal comfort or breathing rate to helping physician to diagnose certain diseases, such as circulatory, vascular problems and the effect of therapies or cosmetic products. In this way, information on the thermoregulatory behavior of the human body is provided, allowing to relate changes in thermal maps, to certain pathologies or to the effect of a treatment, skin affections, varicose veins or joint injuries.
Consuelo Latorre-Sánchez, Juan Antonio Solves-Llorens, Joaquín Sanchiz-Navarro, Ricardo Bayona Salvador, José Laparra-Hernández, Nicolas Palomares Olivares, and José Solaz Sanahuja
Open Access
Article
Conference Proceedings
Orthogonal Curve Analysis of Human Scalp Shape
This paper presents a shape analysis on orthogonal feature curves of 3D bald head scans with the intention of predicting scalp shape under the hair. While there are currently a number of large scale 3D head data collections available around the world, they unfortunately all suffer from hair obstruction preventing an accurate description of true scalp shape. This study is aimed at exploring the relationship between a small set of head anthropometric measurements and the feature curves of the scalp shape based on a small set of 3D bald head scans. The feature curves include scalp profile along the sagittal plane, coronal plane and a cross-sectional curve at the level of glabella.Introduction: The ever increasing availability of 3D scans of the human head has been a valuable source of information for improving head shape related equipment design and engineering with the goal of improving overall fit, sizing and comfort. However the existence of the hair prevents the actual recording and analysis of true scalp shape, and thus the analysis of scalp shape remains an elusive work. For this reason, much of the data analysis based on 3D head scans is mostly limited on facial shape and some facial landmarks. To overcome this limitation, it is desirable to be able to reconstruct the cranium shape from a few easy to obtain anthropometric measurements. In order to achieve this goal we obtained three orthogonal feature curves from 83 bald head scans and build regression equation between principal component scores of these curves and a number of head measurements such as head length, head breadth and tragion-to-top of head distance. The prediction error of these equations are evaluated. The approach: A total of 83 bald head scans taken in the 2012 anthropometric survey of US Army personnel (ANSUR II) from male soldiers are available for the analysis. From these bald head scans we identified three feature curves that principally define the scalp shape. These curves are a profile along the sagittal plane, a profile curve along the coronal plane and a cross-sectional curve at glabella level. These curves are then sampled in an equal angular space and grouped by their respective plane. The collection of each feature curves forms a shape space. We applied Principal Component Analysis (PCA) to those shape curves and decomposed the shape variation of each curve group into its respective principal axes. After conducting the PCA each curve group has a reduced dimension of 4~5 principal components that account for 95% of total variance. It shows major shape variations within each feature curve group. Then we apply multiple linear regression to the above head measurements and PCA scores of each curve group (Principal component regression or PCR). The regression equations for each curve and each PC were evaluated for their predicting power. From these regression equations the constituent feature curves can be selected from respective shape space based on head anthropometric measurements. Then PCR was also applied to the shape space of combined three curves as compared to prediction power in individual curve spaces.The results and discussion: PCR results from all orthogonal curve spaces and combined three curve space have similar predicting power as their R-squared value falling between 0.6 ~ 0.7. With a set of feature curves it is possible to further derive a 3D shape of the scalp. Although the three head measurements used in this study are effectively correlated to the first and second principal component in each group, other principal components contribute to subtle shape variations. This is an area need further analysis. We will also investigate methods to predicting 3D scalp shape from three feature curves and accuracy of the reconstruction of 3D scalp from those curves.
Peng Li
Open Access
Article
Conference Proceedings
Theoretical Framework for the Sizing of Body Armor Plates to Optimize Fit
The development of optimized fitting body armor is critical to the fightability and protection of our warfighters and first responders. Body armor systems generally worn by warfighters consists of three protective portions: rigid plates, a soft armor insert, and a carrier/vest. Rigid plates are inserted into the front, back, and sides of the body armor to provide a higher level of protection for the wearer, while the soft armor is positioned behind the plates and in areas of the body where a lower level of protection is acceptable or required for mobility and comfort. Previously, a comprehensive fit mapping study on the family of armor plates to investigate the relationship between the coverage, anthropometry and mobility relative to size specifications of torso and side plates was conducted (Choi et. al., 2017). There is a delicate tradeoff between covering more (i.e., a greater area of protection) while not degrading the wearer’s mission performance (primarily their mobility). However, some level of mobility degradation is unavoidable. Choi et. al. (2017)'s results quantitatively defined the impact of coverage on mobility, visualized the mobility degradation as coverage increase, and set the allowable mobility degradation to be 10%. The coverage corresponding to the allowable mobility degradation was then converted into anthropometric dimensions. Accommodation envelopes for the current U.S. Army torso plates, relative to the male and female US Army population, were reported. Final size tariffs were calculated using the front plate. A sizing system for the back plate and/or side plates were not developed.This current study explores a theoretical framework for ballistic rigid plate size optimization for the front, back and side plates. When the protection coverage is maximized with minimal mobility degradation, the system would be considered optimized. For this study, minimal mobility degradation was set to 10%. For the front plate, Choi et. al. was revisited to retrieve the maximum width and length while limiting the mobility degradation to 10%. Chest Breadth, was measured using the ANSUR II (Gordon et. al., 2014) procedure, and Suprasternale -Tenth Rib Length was used to derive the width and length of plates, respectively. Then, a specification of the front ballistic plate, given anthropometric characteristics of the current U.S. Army population was developed from a reverse engineering approach. Theoretical accommodation envelopes for each front plate size were then developed and plotted against the current ANSUR II data. Once the front plate sizing system was developed, anthropometric characteristics of cases within each accommodation envelope per size were investigated to develop the required size specifications for the back plate. The width of the back plate shares the width of the matching front plate, but the length takes into account the back length, from the Cervicale -Tenth Rib Length. Size specifications for the side plates were also developed. Given that the front and back plates are worn together; the maximum width of the side plate is defined by the surface availability at the location of the tenth rib level. The side plate length is defined using the distance between Tenth Rib and the Axilla. A theoretical size system for a family of rigid armor plates is presented in a series of tables as well as bivariate plots. A detailed process for plate size prediction and the interaction between the front, back and side plates is presented.
Hyegjoo Choi-Rokas, Todd Garlie, K. Blake Mitchell
Open Access
Article
Conference Proceedings
A Novel Methodology for Evaluating Military Teamwork and Team Marksmanship Performance
Marksmanship has been a key metric in evaluating total Soldier performance. While marksmanship assessment is typically done at the individual level, marksmanship performance is heavily embedded in team tasks and battle drills. Thus, an objectively measured and operationally-based assessment is needed to characterize teamwork in marksmanship tasks, as well as evaluate its impact on team marksmanship performance. This study was a proof-of-concept trial conducted during a 72-hour mission field study, using 39 active-duty male, infantry Soldiers. Thirteen 3-person teams completed a 6-minute scenario that simulated rapidly escalating firing engagement. The teams conducted a planning session to develop strategies for mission accomplishment prior to scenario start. At mission start, the team was situated in the center of a circle of 28 target light emitting diode (LED) displays, which they were required to cover and engage. The target LED displays were in one of three states (dark, non-threat, or threat), each represented by a pattern created by the research team. The scenario was split into six ~60-80 second segments, differing in number of targets presented, target identities (non-threat or threat), as well as density of targets displayed per sector. On-weapon and body sensor data was used to calculate team marksmanship performance (i.e., probability of target hits, probability of threat targets engaged). Additional teamwork data were gathered from observer ratings of teams’ communication and coordination during the scenario, and post-session questionnaires. To evaluate the effects of scenario segment, sector strategy, and communication strategy on team marksmanship performance, two 6x2x2 mixed analyses of variance (ANOVAs) were conducted with scenario segment as the within-subjects variable, and sector strategy (implicit or explicit) and communication strategy (plan or no plan) as the between-subjects variables. Team marksmanship performance outcomes included a team’s probability of hit, p(hit), and ratio of targets engaged, p(engage). Both marksmanship variables revealed significant main effects of segment, p<.001, where performance degraded as the scenario progressed. Additionally, p(hit) had a main effect of sector strategy, where those who used the external environment cues for sectoring (i.e., explicit) resulted in a higher probability of hit as compared to those who used teammate relative positions (i.e., implicit), p=.02. Team communication was trending towards significance, where having a communication plan resulted in lower p(hit), p=.07. For p(hit), there was also a three-way interaction between communication strategy, sector strategy, and segment, p<.01, where teams without a strategy performed more consistently in their shooting across the segments if they had an externally driven sector strategy (i.e., explicit), but performed just the same as those with a communication plan if they had an internally driven sectoring strategy (i.e., implicit). These results suggest that this methodology can not only characterize individual marksmanship skills but is beneficial to assessing team performance across operationally-based scenarios representing escalating short-term engagements and measuring the effects of team variables. However, our proof-of-concept analysis was limited by sample size and future development will strive to increase the number of teams participating. Additionally, future versions of this methodology will incorporate additional metrics of communication, physiology, and decision making.
Stephanie Brown, Peioneti Lam, John Christopher, Richard Goodenough, Jose Villa, Victoria Bode, K. Blake Mitchell
Open Access
Article
Conference Proceedings
Changes on Foot Dimensions with Elevated Heel Heights: A Pilot Study
BackgroundWearing high-heeled shoes (HHS) has been reported to be one of the leading causes of various feet health issues, including hallux valgus, osteoarthritis, ankle sprains, and musculoskeletal disorders. Even so, females are still willing to wear HHS to increase their leg proportions and beauty. Foot dimensions were considered as a primary measure of foot deformation and related to the fitness and comfort of wearing HHS. Footwear designers and manufacturers need to consider these foot dimensional changes with elevated heel heights to fit the foot deformation. However, available information about the changes in foot dimensions with elevated heel heights is still lacking. Hence, the current study aimed to evaluate the change in the nine foot dimensions when wearing HHS with different heel heights.MethodsTen young women (age 23± 3.0 years, height 161.7± 5.5 cm, weight 53.1± 12.5 kg) with foot lengths between 230 to 240 mm were recruited in the pilot study. A 3D foot scanner was used to collect digital foot models, and the nine commonly used foot measurements for footwear design were measured, including foot length, ball of foot length, outside ball of foot length, foot breath diagonal, foot breath horizontal, instep height, navicular height, and toe height. Four elevated heel heights (low heel: 30 mm; medium-high: 50 mm; medium-high heel: 70 mm, and high heel: 90 mm) were selected for evaluation. Each condition was scanned twice, and the mean of the foot dimensions was calculated for analysis. A one-way ANOVA with Tukey post hoc test was performed to evaluate the heel height effect on the measured foot dimensions.ResultsHeel heights significantly impacted foot length, ball of foot length, outside ball of foot length, instep height, and navicular height (all p< 0.01). The result of ANOVA showed that with elevated heel heights (from 30 mm to 90 mm), the instep height and navicular height became higher, whereas foot length, ball of foot length, and outside ball of foot length were shortened. No significant difference was obtained in width-related dimensions and toe height. The Tukey post hoc results indicated that no significant foot dimensional difference was obtained except for foot length between the 30 mm and 50 mm heel height. Moreover, the instep height and navicular height were significantly increased as the heel height elevated from 70 mm to 90 mm.ConclusionsThe heel heights have a significant influence on the length- and height-related foot dimensions, resulting in foot deformations. This effect was especially noteworthy, starting from 70 mm heel height. Observed changes in foot dimensions provide a dimensional reference for shoe last design and footwear production of young women’s HHS. The findings of this study could provide helpful information for designers regarding the foot deformations of young women under different heel heights.
Ao Zhu, Lee Yu-Chi
Open Access
Article
Conference Proceedings
Contact Pressure as an Indicator of Postural Stability in Digital Human Models
This paper presents a natural stability model of Digital Human Models. In the traditional convex-hull-based stability approach, a posture is stable if the Center of Pressure lies within the Base of Support. The posture has no qualitative degree (less/more stable). Additionally, some existing methods use Functional Stability Regions and make the Centre of Pressure lie inside it. Though, this is based solely on experimental observation and lacks reasoning. Hu-mans sense contact/reaction forces. Very low contact pressure may provoke toppling, and high contact pressure induces discomfort. So, humans do not allow forces to rise beyond or recede below certain limits. In this paper, a Sensing-based method that involves estimating pressure at support points is presented to decide whether a posture is stable & comfortable along with its degree. The method provides a rationale for using the Functional Stability Region & applies to any set of support points.
Aijaz Siddiqui, Dibakar Sen
Open Access
Article
Conference Proceedings
Precision of Marker-Based Finger Tracking for Broad Biomechanical Studies Using 6DOF Targets.
In the production the hand is subjected to high loads, because connections between two parts are often done using fasteners. Biomechanical hand models can be found in literature, where systems using single marker tracking showed the highest accuracy. Our system is focused on target tracking, which means tracking of a rigid body with at least 4 markers. The paper therefore describes a 6DOF target tracking procedure and compares the results to a commercial available system within two studies. The first study (n=5) deals with calibrations that are captured for computational determination of anthropometric data. The results show, that the anthropometry is calculated accurate, with e.g. 1.28 mm difference in thickness compared to an anthropometer. The measurement seems reliable with a test-retest variability of less than 10%. The second study (n=5) estimate the accuracy and precision of the fingertips using a design to grasp cylinders. The fingertips penetrate the cylinder 0.8 mm with a RMSE of 2.59 mm. Thus it is possible to measure difference between a gentle and a strong touch.
André Kaiser, Norman Hofmann, Heike Hermsdorf
Open Access
Article
Conference Proceedings
Application of Brain-Computer Interface for Disabled People on Human Factors Engineering
Brain-Computer Interface (BCI) is a new type of human-computer interaction technology, which has achieved good theoretical results so far, but still faces many problems in the practical application of the technology. At present, the main group of people who use BCI technology is the disabled, because this technology can improve the self-care ability of disabled people, but the application design of traditional brain-computer interface in the past did not start from them well. Based on human factors engineering, this paper will analyze the characteristics of disabled people, combine the existing theoretical characteristics of BCI, optimize the application of BCI, and design unique and intelligent application scenarios for them. This can greatly improve people's awareness and acceptance of BCI technology, and promote the development of BCI technology.Keywords: Human Factor Engineering, Brain-Computer Interface, Disabled People, Intelligent Application
Siying Long, Jing Yang
Open Access
Article
Conference Proceedings
Collecting Data for Digital Human Modeling during the COVID-19 Pandemic
In the past few years, the world witnessed a global pandemic due to the widespread of the COVID-19 coronavirus. There are reasons to believe that the associated measures adopted by the respective governments to reduce the spread of the COVID-19 incidences had a drastic impact on the acquisition of subject data. Digital human modeling as many other disciplines of human factors relies on data gathered in participant studies. This led to a massive delay in studies that started before and during the pandemic. This paper compiles protective measures for the acquisition of subject data. Technical, organizational, and personal measures to protect conductors and subjects of studies are presented for future reference.
Martin Fleischer
Open Access
Article
Conference Proceedings
Action Research Arm Test with Multisensory Information
The Action Research Arm Test (ARAT) is a widely tool used by physical therapists to evaluate the performance of the upper extremities in people who have suffered a stroke, brain injury or multiple sclerosis. The ARAT consists of 19 items grouped into four subtests: grasp, grip, pinch, and gross movement. Nevertheless, it’s a subjective test because the score its only based on the interpretation of the therapist who performs it. Therefore, in this work the integration of a Multi-sensory System to the ARAT test is presented. The System developed consists in: an application developed in the software Unity® and in two sensors (an instrumental Glove with bend sensors (CyberGlove II®) and five force sensing resistors (FSR)). The application records the Human Hand Motion data at the moment of realizing the ARAT in real-time (joint angles and fingertip forces) and the data its stored in a database. The application also includes a hand simulation for monitoring purposes. An experimental study was carried out with ten healthy volunteers. Inclusion criteria: over eighteen years old, right-handed, without any injury in their hands, collaborative patients. With the aim of testing and evaluating the performance of the proposed system. The results presented in this paper corresponds at the subtest Grasp and analyze the correlation between fingertip force and the flexion angle of each joint. The proposed system allows therapists and health care professionals a more objective and accurate evaluation. It also serves as the basis for future projects and applications of augmented reality (AR) and virtual reality (VR) about hand rehabilitation due to the compatibility of the Unity ®.
Jesus Fernando Padilla Magaña, Esteban Peña-Pitarch, Neus Tico Falguera, Anas Al Omar, Iñaki Alcelaylarrión
Open Access
Article
Conference Proceedings
Combining Motion Capture with Vibrotactile Feedback for Real-Time Posture Correction
Container lashers are at a significant risk of developing musculoskeletal diseases (MSDs) when working at port facilities. Repetitive strain injuries (RSIs) to the back, shoulders, wrists, and hands, in particular, are widespread. This work investigates the ability of a closed-loop vibrotactile motion guidance (VMG) system to teach an ergonomics-focused approach. The taught technique was developed for tensioning and loosening turnbuckles, an important step in container lashing. During five sessions, two groups, each with three participants, were observed. Participants' initial ability was tested in a baseline session. During this session, participants only receive auditory feedback. A VMG device is used to instruct the experimental group during the next three sessions. Traditional auditory feedback is used to teach the control group. Finally, neither group will wear the VMG device during the follow-up session. The findings of this study suggest that both VMG and auditory feedback training are effective training strategies for reducing postural error state (Wilcoxon Signed-Rank, p < 0.05). However, results suggest that VMG does not provide a significant error state reduction compared to auditory feedback training (Mann-Whitney, p > 0.05).
Alexander Van Gastel, Sander Zelck, Sofia Scataglini, Stijn Verwulgen
Open Access
Article
Conference Proceedings
Design Of A Rehabilitation System Monitoring Gait Of Users With Parkinson’s Disease: Data Visualization As A Methodological Tool
The PASSO project uses a User Centered approach to design and develop a smart system allowing alternative approaches and strategies to the management of motor impairments related to PD. One of the methodological objectives of the project was the improvement of communication in the multidisciplinary team working for the system development. In this paper authors describe how data visualization was used as a project tool giving some benefits as quick information comprehension, a deeper understanding of important factors influencing next stages of the project, a bigger involvement of the group members in the project, and, finally, an increased possibility of achieving results quickly and cheaply, due to more accessible information. In the paper is reported a case study of data representation used in the PASSO project for the communication of results obtained from the testing protocol to the multidisciplinary team.
Silvia Imbesi, Giuseppe Mincolelli
Open Access
Article
Conference Proceedings
Grasp Planning Of Unknown Object For Digital Human Model
ObjectiveGrasp planning is a popular topic in the fields of robotic and Digital Human Model (DHM) (4, 6, 7, 9, 10, 11). So far, the proposed planners do not consider the final posture of the DHM has a criteria when determining potential grasps. In (4), a grasping algorithm has been developed to automatically grasp known tools. The present work introduces a grasp planner for single-hand grasp on an unknown object, further referred as “part”.MethodThe grasp planner gives has a result a grasp pose (position + orientation) for the posture solver (Smart Posturing Engine) to reach. The input necessary to the grasp planner are the 3D model of the object to grasp and of the surrounding environment, and an initial manikin position that is automatically determines by the posture solver algorithm.First the part is approximated by its oriented bounding box (OBB), limiting the grasp poses to 6 (one for each face of the OBB). Then precise grasp types (5) and apertures are chosen based on the face’s dimensions (i.e. width and depth), ranging from a small face (i.e. pinch) to larger ones (i.e. medium wrap or precision sphere).To determine what is the best face of the OBB to grasp, accessibility checks are performed by validating that the space around the face is free of collision. The faces are checked using a specific order (i.e. top, right or left, bottom, front, back) that is determined using the relative initial position of the manikin. As soon as a face is found to be graspable and accessible, the algorithm stops and choose that face as the best one to grasp.Using the selected face target, the hand is positioned using an inverse kinematic solver, free to rotate around the target using extra hand degrees-of-freedom inside a limited range (4). Giving the posture solver more possibilities to find a realistic posture.ResultsThe grasp planner described above leaded to believable grasps for the simulated tasks as well as a believable overall DHM posture. Examples of postures will be shown on assembly tasks performed on a gearbox assembly line.DiscussionThe proposed grasp planner seems really promising. In its current form, it is most suitable for small parts and bigger ones well represented by their OBB. More complex and bigger parts may require further segmentation into multiple smaller sub-parts (9, 10), allowing to perform the proposed checks at more specific and believable locations on the object. This would allow to obtain grasps on a wider range of objects. The object weight is also important and is currently being added to grasp type selection. The present planner is used by the Smart Posture Engine (SPE) framework (1, 2 and 3) inside Dassault Systèmes application “Ergonomic Workplace Design”. With the Ergo4All (12) technology the SPE allows to assess and minimize ergonomic risks involved in simulated workplaces.1. Lemieux, P.-O., Barré, A., Hagemeister, N., Aissaoui, R.: Degrees of freedom coupling adapted to the upper limb of a digital human model. Int. J. Hum. Factors Model. Simul. 5(4), 314–337 (2017)2. Lemieux, P., Cauffiez,M., Barré, A., Hagemeister, N., Aissaoui, R.: A visual acuity constraint for digital human modeling. In: 4th Conference proceedings (2016)3. Zeighami, A., Lemieux, P., Charland, J., Hagemeister, N., Aissaoui, A.: Stepping behavior for stability control of a digital human model. ISB/ASB (2019)4. Bourret, Q., Lemieux, P., Hagemeister, N., Aissaoui, R.: Flexible hand posture for tools grasping. DHM (2019)5. FEIX, Thomas, ROMERO, Javier, SCHMIEDMAYER, Heinz-Bodo, et al. The grasp taxonomy of human grasp types. IEEE Transactions on human-machine systems, 2015, vol. 46, no 1, p. 66-77.6. BEKEY, George A., LIU, Huan, TOMOVIC, Rajko, et al. Knowledge-based control of grasping in robot hands using heuristics from human motor skills. IEEE Transactions on Robotics and Automation, 1993, vol. 9, no 6, p. 709-722.7. Holleman, C.; Kavraki, L.E.; A framework for using the workspace medial axis in PRM planners, in Proceedings 2000 ICRA. Millennium Conference. IEEE International Conference on Robotics and Automation. Symposia Proceedings (Cat. No. 00CH37065), IEEE, Vol 2, 2000, 1408-1413. https://doi.org/10.1109/ROBOT.2000.8447958. FEIX, Thomas, BULLOCK, Ian M., et DOLLAR, Aaron M. Analysis of human grasping behavior: Correlating tasks, objects and grasps. IEEE transactions on haptics, 2014, vol. 7, no 4, p. 430-4419. Díaz, C.; Puente, S.; Torres, F.; Grasping points for handle objects in a cooperative disassembly system, IFAC Proceedings Volumes, 40(2), 2007, 112-117. https://doi.org/10.3182/20070523-3-ES-4907.0002010. Miller, A.T., Knoop, S., Christensen, H.I. and Allen, P.K., Automatic grasp planning using shape primitives. in Robotics and Automation, 2003. Proceedings. ICRA'03. IEEE International Conference on, (2003), IEEE, 1824-1829.11. Goussous, Faisal Amer. Grasp planning for digital humans. The University of Iowa, 2007.12. Bourret, Quentin, et al. "Ergo4All: An Ergonomic Guid
Quentin Bourret, Pierre-Olivier Lemieux, Julie Charland, Rachid Aissaoui
Open Access
Article
Conference Proceedings
Driver Comfort and Gender Inequality Measured with DHMs
Comfort is a subjective measure of how well motor vehicles accommodate the population. With Digital Human Models (DHMs) as drivers, comfort can be objectively evaluated on a 10-point scale with dimensions that measure accommodation of body size and back posture in seat support, controls reach, and lines of sight. In this study, the authors describe how comfort is measured with DHMs in production vehicles. The analysis of 42 vehicles reveals comfort scores by body size are unequal for small females (7.0) and large males (8.25) when compared to the medium-sized males (8.95). DHMs also reveal comfort varies with back posture. Given sexual dimorphism in body size, females are not as well accommodated in motor vehicle interiors as larger males, and seat design contributes to this inequality in the effects of cushion length on pedal reach and head restraint position on eye position for driving.
Mac Reynolds, Sofia Scataglini
Open Access
Article
Conference Proceedings
Assessment of Commercial Off the Shelf (COTS) Sports Brassieres for the U.S. Army Tactical Brassiere (ATB) Program
In an effort to develop a U.S. Army tactical brassiere (ATB), a three-step study was designed and executed. Commercial off the shelf (COTS) sports brassieres were assessed to investigate the effects of different design features on fit, mobility (i.e., breast support, interference), and comfort (subjective rating) relative to the wearer’s anthropometric characteristics (Step 1). Based on the results from the first step of the study, an ATB sizing system was developed (Step 2). Then, the fit model was selected and the accommodation envelope was constructed to develop the brassiere pattern per size based on the ATB sizing system (Step 3). The current study summarizes the results of the first step of the study and includes the relationship between overall coverage, design features, anthropometric characteristics, and their pros and cons as they relate to Soldier mobility.A total of 19 test participants (TPs) volunteered. Data collection sessions were executed following COVID restriction guidelines. Seven configurations (six COTS brassieres and U.S. Army standard issue brassiere as a baseline) were assessed and compared to each other. The six COTS configurations were a combination of three brassiere cup designs (compression, encapsulation and hybrid (more than 1 configuration of cup design)) and two strap designs (straight and racer back). To capture the anthropometric characteristics, a total of 24 traditional dimensions were measured and seven derived dimensions were computed from traditional dimensions. Four additional dimensions were extracted from three-dimensional scan images captured by a Cyberware 3D whole-body scanner. For the mobility assessments, six tasks (Extend and Flex, The Rower, Windmill, Quadraplex, Mountain Climber, and High Jumper) were selected from an Army physical training guide. TPs’ subjective ratings (5-point Likert scale) for support, discomfort and interference on each mobility task were collected upon completion of each task for each test configuration. At the end of the mobility session, TPs provided overall ratings on the attributes of the test configuration. Once data collection on all seven configurations were completed, TPs ranked all test configurations, including their own personal preferred sport brassiere. A one-way repeated measures ANOVA along with Scheffé tests was performed on all applicable anthropometric dimensions. Correlation analyses between anthropometric dimensions and subjective ratings on mobility tasks were conducted to investigate the relationship between design features and mobility. Descriptive statistics, as well as graphical visualization, were produced to compare subjective ratings on mobility tasks between configurations. In all, different brassiere designs had an effect on all compared anthropometric measurements. Each configuration showed distinctive anthropometric characteristics, and those anthropometric differences were often correlated with TPs’ subjective ratings on discomfort and breast support. A detailed investigation for the metrics as well as the comparison of results are further discussed in this paper.
Hyegjoo Choi-Rokas, Edward Hennessy, Stephanie Brown, Linda Desimone
Open Access
Article
Conference Proceedings