I'm the Don B. Chaffin Collegiate Research Professor and Head of the Biosciences Group of the University of Michigan Transportation Research Institute. I conduct research in a variety of areas relating to anthropometry and biomechanics, including vehicle ergonomics and vehicle occupant crash protection. I'm also a Research Professor in the Center for Ergonomics in Industrial and Operations Engineering, where I lead the Human Motion Simulation Laboratory. The HUMOSIM Lab develops movement simulation algorithms and ergonomics analysis tools for use with digital human modeling software.
Follow the links at the right for more information about my research and see these highlights of recent projects.
The Biosciences Group was well represented at the SAE Congress this month. My colleagues presented three papers on a range of topics.
Jones, M.L.H., Park, J., Ebert, S., Kim, K.H., and Reed, M.P. (2017). Effects of Seat and Sitter Dimensions on Pressure Distribution in Automotive Seats. SAE Technical Paper 2017-01-1390.
My colleague Dr. Monica Jones presented work investigating the associations between sitter and seat characteristics and the pressure distribution at the seat-sitter interface. A study was conducted using 12 production driver seats from passenger vehicles and light trucks. Thirty-eight men and women sat in each seat in a vehicle mockup and seat surface pressure distribution was measured on the seatback and cushion. Anthropometric dimensions were recorded for each participant and standardized dimensions based on SAE J2732 were acquired for each test seat. Regression models were effective in predicting characteristics of pressure distribution from the anthropometric variables and SAE J2732 dimensions.
Park, B-K.D. and Reed, M.P. (2017). Characterizing Vehicle Occupant Body Dimensions and Postures Using a Statistical Body Shape Model. SAE Technical Paper 2017-01-0497.
My colleague Dr. Daniel Park presented a novel method for quantifying vehicle occupant postures and body shapes. The methodology was demonstrated using children and a single Microsoft Kinect sensor. The challenge posed by the noisy and incomplete data was addressed by fitting the data using a statistical body shape model (SBSM). The SBSM used in this work was developed using laser scan data gathered from 147 children with stature ranging from 100 to 160 cm and BMI from 12 to 27 kg/m2 in various sitting postures. A principal component (PC) analysis was conducted based on these scans along with the manually-measured body landmarks, and 100 PC scores were retained to account for 99% of variance in the body shape and sitting postures. A PC-based fast fitting method was applied to estimate the occupant characteristics by fitting the SBSM to an incomplete depth image of a subject. The results demonstrate that a fast, inexpensive system can be used to produce useful estimates of occupant characteristics that could be applied to improve personalization of component adjustments, restraint systems, and infotainment systems.
Hu, J., Orton, N., Gruber, R., Hoover, R., Tribbett, K., Rupp, J.D., Clark, D., Scherer, R., and Reed, M.P. (2017). Development of A New Dynamic Rollover Test Methodology for Heavy Vehicles. SAE Technical Paper 2017-01-1457.
The SAE J2114 dolly rollover test is the most widely used vehicle rollover test procedure. However, it requires the test vehicle to be seated on a dolly with a 23° initial angle, which makes it difficult to test a vehicle over 5,000 kg without a dolly design change, and repeatability is often a concern. My colleague Dr. Jingwen Hu presented a new dynamic rollover test methodology that can be used for evaluating crashworthiness and occupant protection without requiring an initial vehicle angle. A custom cart was designed to carry the test vehicle laterally down a track. The cart incorporates two ramps under the testing vehicle's trailing-side tires. In a test, the cart with the vehicle travels at the desired test speed and is stopped by a track-mounted curb. While the cart is being stopped by two honeycomb blocks, the vehicle slides laterally from the cart with the far-side wheels sliding up the ramps, which generates the desired lateral roll rate. The vehicle near-side wheels slide onto a high-friction surface, which generates an additional strong roll moment around the vehicle center of gravity. Three physical tests using three armored military vehicles were conducted using the procedure. All tests resulted in the desired 5 to 8 quarter-turns of the vehicle, and the instrumented tests showed repeatable initial roll rates. The tests demonstrated that the newly-designed rollover procedure is suitable for vehicles that are generally too large/heavy for other dynamic rollover methods, and may also be useful for lighter vehicles when a well-controlled, directly lateral roll is desired.
We recently completed an interesting study looking at upper-extremity activities in driving. We coded nearly 10k snapshots from videos of over 100 drivers who participated in a naturalistic driving study. The activities of the left and right hand and forearm were documented, including contacts (e.g., steering wheel or armrest) and whether they were holding an object. Drivers had left, right, and both hands on the steering wheel in 64%, 46%, and 28%, respectively, of frames in which the hand placements could be determined. The driver’s left elbow was in contact with the door or armrest in 18% of frames, and the driver’s right elbow was contacting the center console armrest in 29% of frames. Women were more likely to have a phone in their right hands than men, and women were twice as likely as men to be wearing sunglasses during trips taken in daylight hours. For more information, see the report, now available online.
I gave a brief presentation at the Midwest meeting of the American Society of Biomechanics this month. Held at Grand Valley State University in beautiful downtown Grand Rapids, the two-day conference featured keynote speakers and a dual track of primarily student presentations covering a wide range of topics in biomechanics. My talk covered some of our recent work in human body modeling, with a particular emphasis on using Microsoft Kinect to create subject-specific avatars. Software developed by my colleague Dr. Daniel Park fits a statistical body shape model to data from a single Kinect sensor, rapidly generating an accurate representation of body shape even for a clothed scan.
My colleagues Dr. Lauren Zaseck and Dr, Jingwen Hu have led the publication of recent work aimed at improving crash protection for soldiers. Vehicle crashes and rollovers, sometimes secondary to IED blasts, are a leading cause of injury. In this project, funded by the US Army TARDEC through the Automotive Research Center, we conducted a series of sled tests to assess the performance of various restraint systems. Hybrid-III ATDs were used along with a range of body armor and body borne gear configurations. The results demonstrated that advanced belt system features such as pretensioners and load limiters substantially improve restraint performance. The data also showed that achieving good belt or harness restraint performance with soldiers in body armor and wearing gear is challenging.
A broad collaboration at U-M several years in the making has produced an innovative tool for visual assessment of child body shape. The lead researchers on the effort are Dr. Julie Lumeng and Dr. Daniel Park. The first validation article on ShapeCoder appeared this month in Pediatric Obesity. The underlying body shape model was developed at UMTRI by Daniel Park and colleagues based on whole-body laser scan data from 147 children. The parametric model used in ShapeCoder allows a rater to select images on screen that best match the body shape of particular child. This tool has value for both estimating the body mass index of children for which measured stature and weight data are not available and for investigating misperception of child body size. An online version of the tool is available. We welcome further collaboration in this domain. Our growing library of body shape models can be used to accurately represent individuals from age 12 months through elderly adults. Please contact me if you have interest in collaborating on further research in this area or applying body shape models.
Dr. Eunjoo Hwang, who recently completed a post-doc fellowship in our group at UMTRI, presented a paper at the Stapp Car Crash Conference this month. This is the most in-depth effort to date to validate parametric finite-element human body models (HBM) by subject-specific comparisons to data from impact tests with post-mortem human subjects (PMHS). Previously, the responses of HBMs have been compared to corridors developed for physical crash test dummies. These corridors have been developed by scaling of PMHS responses (and some low-speed human volunteer test data) to target specific body sizes. But parametric HBM can generate a wide range of body shapes and sizes. Validating this methodology requires comparison to individual subject tests, with the model configured to match the specimen geometry as closely as possible. Although much more work remains to be done in this domain, the results showed clearly that subject-specific models match test data better than naively scaled models.
I gave two presentations at the NHTSA-hosted biomechanics workshop preceding the Stapp Car Crash Conference.
Developing Anthropometric Targets for ATDs Using Statistical Body Shape Modeling
In this talk, I gave an overview of the methodology we used to develop the anthropometric vargets for the Warrior Injury Assessment Manikin midsize-male ATD. This is the first ATD for which the shape and posture targets were developed through 3D statistical modeling of data from a diverse population.
Responses of Minimally-aware Passengers to Abrupt Braking and Steering Maneuvers
I reported on a pilot study of the motions of front-seat passengers who experienced a surprise vehicle manuever, either a hard braking event or a sharp turn followed by hard braking. For this study, we developed a camera-based method for tracking the upper-body posture and motion during the event, as well as capturing vehicle kinematics. We plan to follow this pilot work with data collection on up to 60 volunteers with a wide range of body size and age.
In early October an had the opportunity to visit Chalmers University and SAFER in Gothenburg, Sweden to participate in a dissertation defense. While there I gave a talk on our recent progress on parametric human body modeling. The abstract:
People Are Not Dummies: Modeling Human Variability for Vehicle Restraint System Optimization
Over the past 50 years, crash test dummies (also known as anthropomorphic test devices, or ATDs) have been critical tools for advancing vehicle occupant protection. ATDs allow vehicle manufacturers to design their seat belts, airbags, and other components so that they protect vehicle occupants in a wide range of crash scenarios. However, ATDs are only rough approximations of humans: they have unrealistic body shapes and the need for durability is sometimes achieved at the expense of realism.
In recent years, improvements in computational power and modeling techniques have enabled the creation of highly detailed computer models of human anatomy that can be used to augment ATDs in vehicle design. Currently, most computational models represent people who are the same size as the physical crash test dummies, but our research group has developed methods that allow the existing models to be rapidly morphed to represent a wide range of body sizes and shapes. I'll discuss the rich data we have gathered to characterize the occupant population, the methods and outcomes of model morphing, and the opportunities that we now have to improve protection for the full range of vehicle occupants.
My colleagues Dr. Monica Jones and Dr. Daniel Park participated in the Human Factors and Ergonomics Society annual meeting in Washington, DC this month. Dr. Park participated in a panel discussion on new markerless motion techniques for ergonomics analysis. These methods have great potential for gathering data on worker motions in realistic scenarios without time-consuming and intrusive interventions. Dr. Park's contribution was based on innovative work he's doing using Kinect in concert with our new articulated, rapidly generated subject-specific avatars. Dr. Jones presented work on a new database of body shapes and postures of individuals with high body mass index. Around 5% of US adults have a BMI greater than 40 kg/m^2, and these individuals often experience difficult with the fit and performance of consumer products, vehicles, medical devices, and other products and environments that are too frequently designed for the average. Integrating studies like these with earlier work on body shape modeling, we aim to produce tools that enable the design of products that work well for a wider range of the population.
My colleagues Kathy Klinich and Lauren Zaseck and I participated this month in the annual conference of the International Research Council on the Biomechanics of Injury (IRCOBI) held this year in beautiful Málaga, Spain. We presented and co-authored several papers this year.
Dr. Zaseck presented this innovative simulation study examining the consequence of rib fractures on thorax response. PMHS often have rib fractures due to CPR. Typically such specimens are rejected for biomechanics testing involving the thorax due to concerns that the response would be strongly affected. This simulation study suggests that a small number of rib fractures is unlikely to have a large effect, which also opens the door to more efficient use of PMHS through multiple impacts.
Martínez, L., Reed M.P., Garcia, A., de Loma-Ossorio, M., Torres, C., and Bueno, A. (2016). Crash Impact dummies adapted to People Affected by Osteogenesis Imperfecta. Proc. 2016 IRCOBI Conference. Malaga, Spain.
My colleague Dr. Martínez from INSIA in Madrid presented the results of assembling components from range of crash test dummies to better represent the size and mass distribution of individuals with OI. This work is an important step toward developing improved occupant protection systems for this population.
I presented this work by my post-doc Dr. Jangwoon Park, the latest in a long series of papers on belt fit in vehicle seats for occupants with a wide range of characteristics. The results were similar to those presented previously for drivers, showing a strong effect of BMI on belt fit. Individuals with high BMI tend to have markedly worse lap belt fit than those with normal BMI, potentially reducing safety in frontal and other collisions. The findings confirm the need to look for new ways of improve belt fit and belt performance for all occupants, particularly those who are not shaped like crash test dummies.
Klinich, K.D., Flannagan, C.A.C., Hu, J., and Reed, M.P. (2016). Potential Safety Effects of Low-Mass Vehicles with Comprehensive Crash Avoidance Technology. Proc. 2016 IRCOBI Conference. Malaga, Spain.
My colleague Dr. Klinich presented this innovative study looking at the potential consequences of advanced crash avoidance systems and vehicle lightweighting. Even if a vehicle cannot cause a crash, other vehicles will still collide with it and cause risks to the occupants. Our analysis of current crash data suggests that side impacts will become increasingly important as frontal impacts are reduced and mitigated. This effect is accentuated by vehicle lightweighting, which exposes the occupants to higher accelerations.
I presented this short communication presenting the development of a geometric target for the pelvis of a small-female crash test dummy. Current small-female ATDs have pelves developed by simple geometric scaling of midsize-male pelves. This analysis, which is based on Katelyn Klein's PhD work, demonstrates that linear scaling produces a distinctly unrealistic pelvis shape. We've made the results of this work available online.
My colleages Gale Zielinkski and Frank Huston from the U.S. Army TARDEC presented some of our joint work at the annual Ground Vehicle Systems Engineering and Technology Symposium (GVSETS) in Novi, MI, this month. We have been collaborating for several years on the development of new methods and models for laying out and evaluating military vehicle interiors. The work is based on outcomes from the Seated Soldier Study, our landmark project to gather and analyze data on soldier postures in ground vehicle seats as drivers and squad. The 2016 GVSETS presentation was focused on the development of a CAD implementation of our suite of driver accomodation models for the fixed-heel-point scenarios typical of truck-like vehicles. The image at the right shows the graphical rendering of the models in the Creo parametric CAD system. Based on steering wheel location and the distribution of driver body dimensions, the models generate clearance contours for the head (with helmet), knees, and torso (with body armor and gear). A seat adjustment envelope is generated for a target accommodation level, and an eyellipse graphically illustrates the expected distribution of driver eye locations, which is useful for conducting analysis of driver vision to external and internal targets.
I'm honored to have been named the Don B. Chaffin Collegiate Research Professor by approval of the U-M Board of Regents. The Collegiate Research Professorship is the highest honor awarded to research faculty at the University and is intended to recognize "exceptional scholarly achievement and impact on advancing knowledge." This professorship is named for my mentor Prof. Don Chaffin, a professor of Industrial and Operations Engineering and Biomedical Engineering who led the U-M Center for Ergonomics for many years. Don was a pioneer in the use of biomechanical modeling in ergonomics, leading the development of a human modeling tool for strength assessment that is still used around the world. Don also founded the Human Motion Simulation lab that I now lead. This award is a recognition of the tremendous contributions of my colleagues and students who have created and sustained a highly productive, engaging research enterprise both at UMTRI and in IOE that I am fortunate to be a part of.
I joined my UMTRI colleagues Dr. Monica Jones and Dr. Daniel Park at the Digital Human Modeling Conference in Montreal. Our hosts at ÉTS did a terrific job organizing the conference. We presented work focused on three-dimensional anthropometry and computational simulation of vehicle occupants
Jones, M.L.H., Ebert, S.M., Hu, J., Park, B-K.D., and Reed, M.P. (2016). Quantifying body shape differences between supine and standing postures for adults with high body mass index. Proc. 4th International Digital Human Modeling Conference. Montreal, Canada
Dr. Jones presented a pilot study of the body shape of men and women with high body weight. People with body mass index >40 kg/m2 are almost completely absent from previous body scan study. Yet, such adults are about 5% of the U.S. adult population, and their attributes are critical to set design targets for many products, including vehicle seats and medical equipment. In this study, we also compared supine and standing postures. The goal is to create a linkage
Reed, M.P., Park, B-K. D., and Corner, B.D. (2016). Predicting seated body shape from standing body shape. Proc. 4th International Digital Human Modeling Conference. Montreal, Canada.
As part of a collaborative project with the U.S. Army, we have been exploring many issues related to the measurement and modeling of body shapes. Most scan datasets have a large number of subjects in small number of postures, none of which are functional postures useful for vehicle and seat designs. However, our UMTRI studies typically measure participants in up to 25 postures, including supported seated postures. To make better use of other studies, we developed a statistical model that very accurately predicts seated body shape from a standing scan. We demonstrated the method with civilian female models, but we will be exending this to the male military population.
Park, B-K.D., Corner, B.D., Kearney, M., and Reed, M.P. (2016). Estimating human body characteristics under clothing using a statistical body shape model. Proc. 4th International Digital Human Modeling Conference. Montreal, Canada.
Most body scan surveys measure people minimally clad so that the data best characterize the surface shape. However, in many practical situations it is not feasible to measure people without clothing. Hence, methods for estimating body shape under clothing have great potential utility for building subject-specific avatars. My colleague Daniel Park developed a novel method for rapidly fitting a statistical body shape model to a clothed figure. He demonstrated that the method was surprisingly effective even with soldiers wearing body armor and gear.
Hu, J., Fanta, A., Neal, M.O., Reed, M.P., and Wang, J-T. (2016). Vehicle crash simulations with morphed GHBMC human models of different stature, BMI, and age. Proc. 4th International Digital Human Modeling Conference. Montreal, Canada.
Mark Neal from General Motors presented an overview of a collaboration between UMTRI and GM that is part of our effort to dramatically increase the utility of computational human models for restraint system optimization. Jingwen Hu has led the efforts at UMTRI to develop methods to rapidly morph complex FE models (2M elements) to any arbitrary body size and shape. In this project, the template model is the GHBMC midsize male. The 100 models developed in through this study extend the population represented by that single model through more than 90% of the U.S. adult population based on stature, age, and BMI.
My colleague Dr. Jingwen Hu led a case-study presentation at the annual review meeting of the Automotive Research Center, an Army funded center of excellence at the University of Michigan focused on modeling and simulation of ground vehicles. With our collaborators from TARDEC, Takata, and Oakland University, the presentation outlined a large-scale effort to improve occupant protection in tactical military vehicles, such as the HMMWV, involved in frontal and roll-over crashes. UMTRI's contributions included sled testing, the development of computational models of body armor and gear, restraint optimization, and fitting vehicles for physical testing.
We've completed another analysis of data from the Seated Soldier Study aimed at improving the accommodation of warfighters in military vehicles. This work applies methods that we've previously developed for passenger cars, light trucks, and commercial trucks to the layout of seats and vehicle interiors for the squad seating positions in mlitary vehicles. The seat is parameterized by seat height and seat back angle. The population is described by the distributions of stature, body weight, and erect sitting height, along with gender ratio. For our demonstrations, we use data from the latest U.S. Army Survey (ANSUR II). For squad seating, the models provide a helmet clearance contour, eyellipse, and knee clearance contour. The contours can be set to accommodate any target percentage of the population, such as 95, 98, 99%. These new models provide the first opportunity for the designers of military seat and vehicle interiors to use design tools based on realistic warfighter postures.
The Biosciences Group had a big presence at the SAE Congress in Detroit this month. We presented research on a broad range of topics from seat shape modeling to restraint system optimization for military vehicles. Here are some highlights:
Reed, M.P. and Ebert, S.M. (2016). Evaluation of the seat index point tool for military seats. SAE Technical Paper 2016-01-0309. SAE International Journal of Commercial Vehicles.
In the design of on-highway vehicles, the SAE J826 H-point machine is used globally to establish reference points and angles to define the seat position and orientation. However, the H-point machine doesn't work very well in many military vehicle seats. In this paper, we compared the performance of the ISO 5353 seat index point tool (SIPT) to the H-point machine and found that not only is it more stable, but it gives comparable results in many situations. Consequently we recommend that the U.S. Army immediately adopt the SIPT as the standard for measuring ground vehicle seats whenever the H-point machine cannot be used or is not available.
Drignei, D., Mourelatos, Z., Kosova, E., Hu, J., Reed, M.P., Rupp, J.D., Gruber, R., and Scherer, R. (2016). Uncertainty assessment in restraint system optimization for occupants of tactical vehicles. SAE Technical Paper 2016-01-0316. SAE International Journal of Materials and Manufacturing, 9: 436-443
We are in the final stages of a large-scale project developing optimized restraint systems for a Humvee-like vehicle to protect its occupants in frontal-crash and rollover events. We conducted sled testing of a variety of restraints with fully equipped soldiers, then performed a wide-ranging simulation study to identify optimal restraints, including airbags for frontal crash protection. One challenge in restraint system optimization is that the complexity of the computational models for simulating crashes means that we can't run as many physical or computational tests as we would like. This paper explores a method for estimating the uncertainy in outcomes given a small number of test results.
Hwang, E., Hallman, J., Klein, K., Rupp, J.D Reed, M.P. and Hu, J. (2016). Rapid development of diverse human body models for crash simulations through mesh morphing. SAE Technical Paper 2016-01-1491. SAE International, Warrendale, PA.
Our postdoc Eunjoo Hwang presented some of her work on parametric modeling of vehicle occupants. The work reported here was actually completed about 18 months ago and represented the first project we're aware of to successfully morph a high-fidelity human body model (THUMS4, in this case) to a wide range of body sizes. With leadership from Dr. Jingwen Hu, we have extended this broadly, generating over 100 anthropometricallly distinct versions of THUMS4.
Jones, M.L., Ebert, S.M., and Reed, M.P. (2016). A Pilot Study of Occupant Accommodation and seat belt fit for law enforcement officers. SAE Technical Paper 2016-01-1504. SAE International, Warrendale, PA.
My colleague Dr. Monica Jones presented some interesting pilot work she conducted assessing the geometric fit of law-enforcement officers (LEO) in vehicles with a focus on seats and restraint systems. Car crashes are a leading cause of death for LEO in the U.S., with more officers killed in vehicles than by guns. Some officers report that they do not wear their safety belts because they do not fit well when they're wearing their duty belts, and lower-back and other musculoskeletal ailments due to poor vehicle ergonomics are a leading cause of lost work time for officers. In this study, Monica used 3D laser scanning to document the mismatch between LEO and their seats and vehicles. More work is needed in this area to improve vehicle designs for law enforcement.
Park, J., Ebert, S.M., Kim, K.H., Jones, M.L., Park, B-K, and Reed, M.P. (2016). Development of an automatic seat-dimension extraction system. SAE Technical Paper 2016-01-1429. SAE International, Warrendale, PA.
Dr. Jangwoon Park, a post-doc in our lab, developed a novel automated software system for extracting seat dimensions. In the auto industry, seat benchmarking is a slow process. Extracting the dimensions defined by SAE J2732 can take hours. Dr. Park's system can compute dimensions in minutes from a 3D scan of the seat, assuming H-point data are available. We are exploring the potential of combining this system with the statistical shape modeling methodology described below to create a new, quantitative system for evaluating vehicle seating.
Kim, K.H., Ebert, S.M., and Reed, M.P. (2016). Statistical modeling of automotive seat shapes. SAE Technical Paper 2016-01-1436. SAE International, Warrendale, PA.
My colleague Dr. Han Kim developed an interesting approach to analyzing seat shapes. Observing the organic contours typical of modern auto seats, he applied the same methods we've been using in recent years for modeling human body shape. He developed a semi-automated method for fitting a template to each seat so that the contours are amenable to a statistical analysis using principal component analysis and regression. The resulting parameterization can be used for a host of interesting applications, including seat shape clustering, interpolating among seats, finding the "nearest neighbor" of a seat, and designing completely new seat shapes. The potential of this new tool will begin to be realized after we are able to add perhaps 100 more seats to the database.
Thanks to the great work of my colleague Dr. Daniel Park, we have launched a beta version of our new web portal, HumanShape.org. HumanShape will provide interactive, online access to our many statistical body shape models. Already, this is the only online source of data on child body shape and seated adults. Much more will be coming in the next few months. Currently, the site hosts three child anthropometry models and one adult model. Users can input the overall body dimensions, such as stature and body weight, and download an STL file along with a range of body landmarks. We welcome feedback and suggestions on how we can make this tool useful for a wide range of applications.
Anthropometric data on children are scarce, and anthropometric data on toddlers and infants are even more rare. My colleagues and I just wrapped up a preliminary analysis of an unprecedented dataset of 3D whole-body laser scans of toddlers ages 12 to 36 months. Using methods we previously applied to children ages 3 to 11, we developed a statistical body shape model parameterized on torso length (erect sitting height for children who could assume that posture, recumbent length for the younger ones) and body mass. The resulting model was used to generate a set of boundary manikins based on increments of body weight. These tools will be useful for child restraint design, in particular for ensuring that harness strap heights accommodate nearly all children within the weight ranges by which restraints are specified.
My colleagues in the Biosciences Group and I are heavily involved with other researchers across the country in a program to develop a new anthropomorphic test device (ATD or dummy) for underbody blast testing. The Army currently uses the Hybrid-III ATD, which was developed for frontal crash testing in automobiles. Our group is conducting vertical impact testing using our droptower to develop the basic biomechanical performance targets for the ATD. We have also had primary responsibility for developing the anthropometric specifications for the ATD. The image to the right is an early prototype concept originally developed by Humanetics and brought to fruition by DTS. Among our contributions to this design are the design of the overall body shape and joint locations, head contour, pelvis shape, design posture, and foot contour. This is the first ATD in which the anthropometric specification is based on a statistical analysis of whole-body shape data. It follows a long tradition at UMTRI of the development of anthropomorphic human surrogates for safety applications.
My colleagues and I attended the Stapp Car Crash Conference in New Orleans this month. During the sessions, we received an award for the best paper at the previous years' conference. Dr. Lauren Zaseck was the lead author on the paper, which was the first to look closely at the side-impact response and tolerance of older and female PMHS. Because these populations are greater risk of serious injury, test procedures, ATDs, and injury criteria need to take their needs into account.
AutoBeatDaily has a nice piece on recent work we did with ZF TRW aimed at improving occupant protection in rear seats. My colleagues Jingwen Hu, Steve Peterson and I were interviewed about the collaboration between ZF TRW and UMTRI on this NHTSA-funded project. The overall goal of the effort was to develop optimized restraint systems for occupants of various sizes in second-row, outboard seating positions. The best-performing system included a unique, self-configuring airbag design that provides good head protection for occupants with a wide range of body size. Future work will consider the effects of alternative and adaptable belt and seat geometries.
The BBC did a great piece on our work over the past few years to improve accommodation and safety for soldiers in vehicles. This work was funded by TARDEC through the Automotive Research Center. This effort has involved a large number of U-M and TARDEC collaborators. The dataset from the Seated Soldier Study is now the primary information the Army uses in determining the posture, shape, and space claim for soldiers in vehicles. This work for the Army is part of wide ranging research program in the Biosciences group to quantify how people sit in vehicles, as well as how they get in and out and move around in them. We have pioneered the use of 3D human surface measurement and modeling in this domain and are increasingly using markerless technology, such as Microsoft Kinect, to measure motion as well as posture.
I presented a short communication at the IRCOBI annual conference in Lyon, France. A substantial part of our current research focuses on measuring and modeling body shape. Many of our applications relate to automobile crash safety. Using whole body scan data, we analyzed the contour of the lower abdomen in the area where the lap portion of a three-point belt is routed. We found that the length of this contour is strongly associated with body mass index (BMI), which is a useful surrogate for adiposity. Age had a small effect, but gender was unimportant. This research is consistent with our previously published work showing that high BMI is associated with relatively poor lap belt fit. That is, high-BMI individuals tend to place the belt higher and more forward relative to the pelvis. The current study confirms that the effect can be largely accounted for by lower abdomen protrusion, a finding that is not unexpected, but is now quantitatively demonstrated. We have previously published human simulation studies demonstrating the consequences of high BMI for drivers, which are consistent with our analysis of field crash data. We are currently underway with studies to evaluate the effectiveness of advanced belt systems and other countermeasures to improve restraint performance for the 1/3 of U.S. adults who are obese.
Locating body surface landmarks on whole-body scan data is usually a time-consuming manual process. Manual digitizing is the "gold standard", producing higher accuracy and precision than automated methods, but for some applications a rapid, fully automated procedure is desireable, even if accuracy is lower. I presented a brief paper at the IEA conference in Melbourne, Australia, this month examining the precision of a purely statistical method for predicting landmark and joint locations. The method is based on a statistical body shape model that incorporates landmarks and joints. The results showed that the predictions for torso joints are surprisingly precise when scan data is fitted using a rapid optimization process. The most important near-term application is the estimation of a kinematic linkage for avatars created from Kinect scan data.
The Biosciences Group is conducting a broad range of research for the U.S. Army, including a large-scale study focused on improving protection for soldiers in vehicle crash and rollover events. At the 2015 GVSETS meeting, my colleague Dr. Jingwen Hu presented an overview of outcomes from a sled-test series comparing the performance of alternative belt restraint systems in frontal impact. This is the first study to examine the influence of restraint system configuration across a range of body size, taking into account the effects of body armor and body borne gear. This work was recognized with a "best paper" award, one of only 2 out of 53 peer-reviewed papers to receive this honor.
My colleagues Dr. Daniel Park and Dr. Jangwoon Park presented some recent work at the Applied Human Factors and Ergonomics (AHFE) annual meeting in Las Vegas. Dr. J. Park presented a new method for estimating pelvis position and orientation in automobile seats. This perennially challenging problem is more difficult in individuals with high BMI, and the new methods enable adjustments to account for larger flesh margins. Dr. Daniel Park presented methods for mapping a statistical body shape model generated on one manikin mesh to another mesh. This method allows us to apply our model outcomes much more broadly. In particular, we can rapidly generate a CATIA manikin automatically from Kinect scan data.
Analyses of crash data in the field have shown that obese occupants are at higher risk in frontal crashes than occupants of normal weight. Improving protection for obese occupants requires an understanding of how these occupants interact with restraint systems. At the 2015 ESV Conference in Gothenberg, Sweden, my colleague Jingwen Hu presented a simulation study aimed at understanding how obese occupants interact with belts in frontal impact. This work is based on a new paradigm in parametric human modeling that allows rapid, accurate morphing of complex finite element models to represent individuals with a wide range of size and shape. This study validated a set of obese occupant models using post-mortem human subject data from testing conducted at the University of Virginia.
Wang et al. (2015), A Simulation Study on the Efficacy of Advanced Belt Restraints to Mitigate the Effects of Obesity for Rear-Seat Occupant Protection in Frontal Crashes Traffic Injury Prevention, 16:S75-S83, doi:10.1080/15389588.2015.1010722
Daniel Park and I have just published the first parametric body shape model for children. The model is based on laser scans of 137 children ages 3-11 in a standing posture. We used a custom template fitting approach followed by standard PCA+regression methods to create a statistical body shape model parameterized by stature, BMI, and the ratio of sitting height to stature. This model is now available online at childshape.org. As far as we know, this is the first data-based body shape model to be made available for free online. The online versions allows for downloads of a mesh surface (STL) file along with body landmark and joint locations and a set of standard anthropometric dimensions. We expect to be putting many more models online in the next year as we published more of our body shape studies. Please contact me if you have questions about using the model in your research.
The UMTRI Biosciences Group was featured in an article in Mechanical Engineering, the monthly magazine of ASME. The work of my colleague Dr. Jingwen Hu and his students on parametric human body modeling for restraint system optimization was highlighted. The article touches on a range of activities now underway in our greoup, including whole-body scanning and body shape modeling, finite-element modeling of highly detailed human anatomy, and restraint system optimization.
My collaborator Matt Parkinson, his student Brian Pagano, and I have just published the first updated assessment of U.S. child anthroometry in a generation. During the 1970s, UMTRI researchers led by Jerry Snyder conducted two large-scale studies of child body dimensions, measuring thousands of children across the country. Since that time, children in the U.S. at each age have gotten considerably heavier, with greater differences at older ages. Dr. Parkinson and I have previously published statistical methods for adjusting a detailed dataset to match a population for which only overall body dimensions, such as stature and weight, are known. We applied a similar methodology to update the detailed dimensions in the Snyder 1977 study based on recent stature and body weight data from the U.S. National Health and Nutrition Examination Survey. This update will be valuable for anyone who creates products or environments for children in the U.S. including child restraints, furniture, and clothing. Ultimately, a new, comprehensive study of U.S. child anthropometry is needed. Contact me for an article reprint.
The final report for the Seated Soldier Study conducted by UMTRI for the US Army TARDEC is now available. The report describes the methods and results from detailed measurements of 315 soldiers at three Army posts. A detailed posture analysis was conducted for both driver and squad seating conditions. Posture-prediction models based on UMTRI's Cascade methodology are presented for both environments. The models take into account the effects of body armor and body borne gear. Whole-body laser scanning was conducted to characterize body shape with and without PPE and gear. Analysis of this rich dataset will be underway for some time. Already, we are working on accommodation models for driver and squad condition, new vehicle packaging paradigms, and methods for optimizing seat design based on these findings and data. Three-dimensional body shape modeling using a subset of data from the Seated Soldier Study was used to develop anthropometric specifications for the midsize-male WIAMan ATD. If you have additional ideas on how these data could be used to improve the design of vehicles, seats, and protective equipment for soldiers, please contact me.
Building on recent work on body shape modeling and using Kinect as a body scanner, I presented a paper at the 2014 HFES conference in Chicago on work with Siemens on generating subject-specific Jack models. In May, we presented work at the 2014 DHM conference on the implementation in Jack of standing male and female statistical body shape models (SBSM). For some applications, it is useful to create a Jack manikin of a particular individual, for example, a subject in a laboratory study. Normally we would take a set of a dozen or so standard anthropometric measures and type them into Jack to scale a custom figure. That figure will have roughly the right size, but often the shape is quite unlike the individual. In the current work, we find the set of principal component scores in our male or female shape model that produces the body shape most closely matching the data from a snapshot taken with the Kinect sensor.We then pass those PC scores to Jack to obtain a figure with very similar size and shape. The paper shows quantitative comparisons for four women scanned with the Kinect system. In future work, we'll apply the new Kinect 2 sensor, which promises greater accuracy, and relax the current restrictions on scanning posture.
I presented a short communication at the 2014 IRCOBI conference in Berlin this month addressing driver knee locations. In modern vehicles, the underside of the instrument panel is designed to absorb energy in frontal impacts by exerting controlled force on the driver's knees. The knee bolster is an important component of the restraint system, sharing load with the steering wheel airbag and three-point belt. In recent work, we showed that the lap portion of the belt fits considerably more loosely for most people than for crash dummies. A loose belt means that the occupant will translate further forward before belt force builds up, potentially changing the load sharing between the belt and knee bolster. The starting knee location at the time of the crash is one critical determinant of load sharing. We used data from 100 men and women with a wide range of body size who sat in a laboratory vehicle mockup in 9 different vehicle configurations spanning the range from sports cars to SUVs. We used regression analysis to model the location of the forward-most margin of the patella (kneecap) as a function of vehicle and driver variables. As expected, the vehicle configuration had a strong effect, but we also found that taller drivers' knees are more rearward, on average. These results are useful for understanding the distribution of drivers' knee locations in any particular vehicle and could be used to conduct parametric studies of load sharing for a range of frontal impact conditions.
I presented an update of our virtual seat fit assessment work at the 8th Annual Automotive Seating Innovators Summit in Detroit. This collaboration builds on work my colleague Jingwen Hu presented at the SAE Congress in 2013. The critical insight behind this work is that rigorous dimensional assessments of seats requires evaluation with hundreds or even thousands of people. Since it's not remotely practical to do that with physical prototypes, virtual seat fit evaluations with synthesized populations of sitters is the only way to conduct an accurate dimensional analysis considering all geometric aspects of the seat sitter interaction, rather than just a few standard anthropometric dimensions. The previous work used 3D body shape models based on CAESAR. The work now underway will apply body shape models based on UMTRI data gathered in a number of studies.
The Automotive Research Center at the University of Michigan held its Annual Review this month, celebrating 20 years of research in modeling and simulation of ground vehicles. I presented an overview of some of our activities in Thrust Area II, Human-Centered Modeling in Simulation. Among other projects, we are studying the effects of body armor and body borne gear on seated reach difficulty and capability; developing new statistical tools for vehicle interior layout based on soldier posture data; and conducting sled tests and finite-element simulations to optimize belt restraints and airbags for tactical vehicles.
My colleague Daniel Park presented a paper at the 3rd International Digital Human Modeling Symposium on our work with using Kinect sensors for body scanning.
Our technique uses only two Kinect sensors and requires only about 12 seconds to obtain a subject-specific avatar. The key innovation is a rapid application of a statistical body shape model based on body scan data. The method is demonstrated using children between ages 3 and 11.
Prof. Matt Parkinson of The Pennsylvania State University presented some joint work on human modeling at the 3rd International Digital Human Modeling Symposium.
The paper reports a collaboration with Siemens to implement a statistical body shape model based on scan data in the Jack human modeling software. To our knowledge, this is the first time a widely used commercial ergonomics tool has included a high-resolution body shape model based on a statistical analysis of scan data.
This paper won an Applied Research Award at the conference.
I was fortunate to have the opportunity to present an overview of our research on tactical vehicle occupant protection at the U.S. Military Academy at West Point. LTC Bruce Floersheim, Director of the Center for Innovation and Engineering, hosted my visit.
The research I presented was funded by TARDEC through the Automotive Research Center at the University of Michigan. The ARC is a U.S. Army Center of Excellence in modeling and simulation of ground vehicles.
I gave a briefing at the U.S. Army Tank-Automotive Research, Development, and Engineering Center this month on our Seated Soldier Study. In close collaboration with the Army, and with assistance from Anthrotech, we measured the seated postures and body shapes of over 300 soldiers. This study is the first we are aware of to document in detail the effects of body armor and body-borne gear on supported seated postures. Major outcomes of this work include new posture-prediction models for drivers and squad members in military vehicles. In addition to posture measurements, over 8200 whole-body surface scans were obtained using a laser scanner, documenting male and female body shape in up to 20 postures. Along with our related work on civilian vehicle occupants, this study provides the first large-scale data on body shapes in supported seated postures. We have used the data to generate statistical models of body shape for use in a wide range of engineering applications.
The Seated Soldier Study was funded by TARDEC through the Automotive Research Center at the University of Michigan. The ARC is a U.S. Army Center of Excellence in modeling and simulation of ground vehicles.
©2017 Matthew P. Reed and The University of Michigan