engineering anthropometry
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Engineering Anthropometry. Anthropometry – the study of human body dimensions - PowerPoint PPT PresentationTRANSCRIPT
Dept. of Biomedical, Industrial, & Human Factors Engineering 1
Engineering AnthropometryAnthropometry – the study of human body dimensions
Imagine you are positioning an emergency "rip cord" on a train. How high up should you put it? So people can reach it! is the obvious (and correct) response. One way to arrive at an answer is to ask your friends to give it a try. But to get values that are in any way robust (especially if the product is to be used by different nationalities), it is necessary to turn to the science of anthropometrics.
Example: I’m 68 inches tallIn USA/UK, I’d be in the 35-40th percentileIn Japan, I’d be in the 75-80th percentile
Links to look at:Anthropometry Resource Center People with Disabilities
Dates back to ancient EgyptCubit (~52 cm) – based on human dimensions (distance from elbow to tip of longest finger)Large scale anthropometrical surveys are expensive and time consuming
Typically do specialized surveys on key dimensions
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CAESAR Research ProjectCAESAR: A 3-D anthropometric research project that will generate technologically advanced data on the size and shape of the modern human body.
The companies supporting this $6 million project include: Boeing, Caterpillar, GM, John Deere, Levi Strauss, Magna Interior Systems Engineering, Navistar, Sears, Transport Canada, Visteon, Case Corp. Ford, Jantzen, Johnson Controls, Lee Company, Lockheed Martin Aeronautical, Mitsubishi Motors, Nissan Motors, Sara Lee Knit Products, and Vanity Fair, Inc.
Collecting the measurements of 10,000 people, ages 18 to 65, at eight sites in the U.S. and in Europe.
Expected to be completed Fall 2000.
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Wright-Patterson (USAF) Involvement
The tests will use equipment from Cyberware, (Monterey, Calif.) that was originally developed for a Wright-Patterson Air Force Base program called Computerized Anthropometric Research and Design (CARD).
The Air Force used it to develop a means of determining if its clothing and tools were the most effective size and shape, and that pilot stations within aircraft were the most efficient possible.
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Whole Body Scanner
Other sites:http://www.industry.net/discussions/Features/caesar_measure.htm
http://www.af.mil/news/May1998/n19980520_980697.html
Whole Body Scanner
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Engineering Anthropometry for Design
DesignClothingWorkspaceEnvironmentEquipment, tools, & machineryConsumer product design
Design IdeaAccommodate the body characteristics of the population Universal operability is 90-95% of the populationBuild in adjustment to meet objectivesSome dimensions only require one set of dimensions
Example: 95% reach
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Measurement DevicesCalipers – spreading and sliding
Anthropometer – rods with one fixed
Tapes – measure circumferences and contours
Simple scales – weightCones and boards with holes – grip circumference and finger sizePhotographicElectronic scanners
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Human VariabilityIs there a Average Human?Humans vary in dimensions based on
GenderEthnic groupsNationalitiesEtc.
Over 300 anthropometric measurements on the bodyIt is hard to say that any one person is 50%-tile on all measurements
Factors affecting Anthropometric dataAge – body dimensions begin to increase with age and then decrease around 40Gender – men are generally larger than women at any given percentile and body dimensions except hips and thighs
Ethnic differences cause further differences
Body PositionPosture affect size
Clothing – clothing adds to body size plus restricts movement
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Design and Use of Anthropometric Data
Design for the Extreme -- An attempt to accommodate all (or nearly all) of the population
Design for the maximum – if maximum value accommodates all (e.g., height of door, escape hatch in airplane)
Design for the minimum – if minimum value determines if all are accomodated (e.g., distance to control button from the operator (reach); amount of force to press a button)
Design for Adjustable Range – design to accommodate all (e.g., office chairs, desk height, key board height)
Range typically is 5th percentile of females to the 95th percentile of males in relevant characteristics
Design for the Average – there is no average humanThere are times when the average may be acceptable (e.g., counter height at grocery store)
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Design and Use of Anthropometric Data
Design Principles DiscussionSetting limits to 5th and 95th percentiles can eliminate a fairly high percentage of population
Bittner (1974) – looked at 5th and 95th percentiles on 13 dimensions
Would have excluded 52% of population instead of 10% implied by percentiles
Why? – body measurements are not perfectly correlatedShort arms short legs
To derive composite measures taking into account imperfect correlations requires regression analysis
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Design and Use of Anthropometric Data
General approach1. Determine body dimensions important in the design
Example: chairpopliteal height (lower leg length), seat depth (buttock to popliteal length) hip breadth, midshoulder sitting height (back height), elbow height, lumbar height lumbar depth
2. Define population (e.g., adult - male, adult - female, children)3. Determine what principle should be applied4. Select % of population to be accommodated5. Locate anthropometric tables appropriate for the population6. If special clothing worn – add allowances7. Build prototype and test using representative tasks
Anthropometric dataStructural dimensions – taken in standard & still positionsFunctional dimensions – obtained in various work postures
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Percentile Covered
Herman Miller found that chairs theoretically designed to fit the 5th-percentile female to the 95th-percentile male actually fit far fewer people (Dowell, 1995a).
Source: Herman Miller Workplace Research http://www.hermanmiller.com/research/essays/aeronessay2/essay2.html
Return:
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Anthropometric Data - structural
Source: OSHA Draft Ergonomics Standard (Appendix D)
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Anthropometric Data - structural
Source: OSHA Draft Ergonomics Standard (Appendix D)
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Anthropometric Data - dynamic
Modeling Reach Distance
Source: NASA
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Anthropometric Data - dynamic
Source: NASA
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Software
Mannequin (Humancad, Melville, NY) and Jack (Center for Human Modeling and Simulation, University of Pennsylvania, Philadelphia, PA) enable designers to determine the best digital reach zoneExample from JACK
Source: http://www.cis.upenn.edu/~hms/jack.html