Three-Dimensional Child Anthropometry for Vehicle Safety Analysis. Matthew P. Reed Sheila M. Ebert-Hamilton Biosciences Group October 2012

Transcription

1 Three-Dimensional Child Anthropometry for Vehicle Safety Analysis Matthew P. Reed Sheila M. Ebert-Hamilton Biosciences Group October 2012

2 Children in Cars Data on the size, shape, and posture of children are needed for: Developing ATDs! CRS Design! Developing Computational Models! Optimizing Belt Restraints!

3 Child Anthropometry The most recent large-scale, detailed study of U.S. children was conducted by UMTRI (HSRI) in the 1970s for the US Consumer Product Safety Commission The ongoing U.S. NHANES gathers stature, body weight, and a few other dimensions, but this information is insufficient for product design and analysis

4 Standard Anthropometry Anthropometers, calipers, and tape measures: 1D dimensions Snyder et al. (1977)!

5 Child Body Shells The current Hybrid-III 3YO and 6YO ATDs are based on standard anthropometry and 3-D surface representations based on 1-D data created in the early 1970s 6YO! 3YO! Young et al. (1975)!

6 Functional Anthropometry Measure physical attributes in task-relevant conditions Measuring posture by digitizing the 3D locations of body landmarks Measuring belt fit

7 Multivariate Functional Anthro Vehicle and Seat Geometry! Target Body Dimensions: Stature, Body Weight,! Regression! Measure Landmarks in Seated Postures! Principal Component Analysis! Whole-Body Landmark & Joint Configurations! Joint Center Location Estimates! Large Child Omnidirectional Dummy (Humanetics ATD) Crash Dummy Anthro Specs!

8 UMTRI Child Body Shape Study Objective: Quantify body shape and vehicle seating postures for children ages 4 to 11 Posture and belt fit in vehicle seating Standard anthropometry Whole-body scanning

9 Subject Pool Total 162 children (78 boys, 82 girls), ages 4 to 11 Hybrid III Reference Dimensions 3YO 6YO Small Female Adult 10YO

10 Methods Standard Anthro 23 standard anthropometric dimensions taken to document child size Methods match previous large-scale UMTRI child anthropometry study (Snyder et al. 1977) where possible

11 Methods Landmarking Total of 92 landmarks measured directly (FARO Arm) or digitized in scan data 33 landmarks measured with FARO Arm in vehicle seat and booster conditions

12 Methods Vehicle Seat Child posture and belt fit measured in a midrange vehicle seating condition with and without a belt-positioning booster Provides a direct linkage to previous UMTRI laboratory and invehicle child posture and belt-fit studies

13 Methods Scanning VITUS XXL scanner from Human Solutions Lasers travel top to bottom, painting a red line on the subject 12-second scan time, approximately 500k points per scan, depending on subject size Two cameras on each tower view laser line, convert to coordinates Four laser towers with eye-safe red light Custom platforms for standing and seated conditions

14 Methods Scanning Pelvis points recorded in some postures using FARO Arm Lap area (shadowed from Vitus scanner) was manually scanned using FARO-Arm laser scanner in some postures

15 Methods Standing Postures T-Pose Arms Abducted Erect Natural

16 Methods Unsupported Back ISO Standard Posture Lap Coverage

17 Methods Unsupported Buttock Half-seat Up Half-seat Down

18 Methods Supported Back Booster Recline 1 Recline 2 Recline 3 Recline 4

19 Methods Arm ROM 90 Abd Max Ext Max Abd 90 Flex Max Flex

20 Methods Spine ROM Flex 3 Flex 2 Flex 1 Ext Max

21 Body Shape Modeling Whole-Body Scan Data Handheld Scanner Data Clean and Fit Polygon Mesh Manual Landmark Extraction Manually Measured Body Landmarks Model Integration Mesh with Landmarks Segment and Resample Mesh Standard Anthropometry PCA+Regression Analysis Statistical Model to Predict Body Shape from Standard Anthro or Landmark Locations

22 3D Anthro: Statistical Modeling Adult Models from Previous Work!

23 Skeletal Anthropometry Parametric Modeling of Skeletal Structures 2 nd PC of Ribcage Shape CT Images Statistical Modeling Data Extraction (N > 100) Predicted Skeleton Size and Shape = ƒ (stature, mass, ) Hybrid-III vs. Human Pelvis

24 Model Development Body Shapes from Current Study Vehicle Environment seat back angle seat cushion angle seat cushion length booster/no-booster Child Attributes stature body weight gender? Posture Prediction: Landmark and joint locations relative to seat Body Shape Prediction: Surface mesh Skeletal Geometry Prediction: Bone meshes Integrated Child Anthropometry Model Skeletal Modeling from CT Lab and In-Vehicle Child Posture Studies

25 Next Steps and Future Work Complete data analysis and modeling Develop body shape targets for crash test dummies across the range of relevant sizes and postures Apply results to morphing to human-body FE models

26 Acknowledgements This research was funded by NHTSA under contract DTNH22-10-H with the University of Michigan!!! Contacts:! mreed.umtri.umich.edu!!

27 Scan Data Processing First step is manually stripping props Raw scan data for some of the study postures!

28 Scan Data Processing Hand-scan data are integrated and holes are filled!!!!!!!

29 Scan Data Processing Visible landmarks manually extracted using Meshlab software from scans with grayscale texture Multiple trials to quantify repeatability and reproducibility Combined with FARO Arm coordinate measurements

30 ATD Applications