Ergonomics Standards - CoG Human Body
Ergonomics Standards - CoG Human Body
(OP)
Hello,
I am currently looking for a definitive standard that can be used in the creation of a percentile ergonomic model.
I have found a NASA document that shows some of the lengths of various limbs, torso's and the suchlike. However I cannot find any reference to the center of gravity of the items.
My overall goal is to create a "simple" 2D stick model, using the lengths and sizes provided and then a overall CoG can be calculated. This stick model is then to be modelled in Adams to visualise the movement and record the new position of the centre of gravity throughout the simulation.
Does anybody know of any standards that may be able to help me in the creation of the model?
I presume that this could be completed using industry standard 3D models and simulation packages but currently I do not have the budget to support this exercise..... Hence the calculation route.
Many thanks
I am currently looking for a definitive standard that can be used in the creation of a percentile ergonomic model.
I have found a NASA document that shows some of the lengths of various limbs, torso's and the suchlike. However I cannot find any reference to the center of gravity of the items.
My overall goal is to create a "simple" 2D stick model, using the lengths and sizes provided and then a overall CoG can be calculated. This stick model is then to be modelled in Adams to visualise the movement and record the new position of the centre of gravity throughout the simulation.
Does anybody know of any standards that may be able to help me in the creation of the model?
I presume that this could be completed using industry standard 3D models and simulation packages but currently I do not have the budget to support this exercise..... Hence the calculation route.
Many thanks





RE: Ergonomics Standards - CoG Human Body
Patricia Lougheed
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RE: Ergonomics Standards - CoG Human Body
Finding the CG would be difficult because it is (generally) significantly different for men and women (Men's is typically higher).
I suggest finding a swing or horizontal bar and laying flat across it. When you are in a position where it is easy to balance while remaining in a flat, normal position, that's about your CG... Get everybody you can and repeat to increase sample size.
I suspect that there will be significant variation, even within genders. I don't know that the data is going to supply a much more concrete answer than you could achieve by making an educated guess (mine would be at the belly button).
-- MechEng2005
RE: Ergonomics Standards - CoG Human Body
Anyway, the relevant part is that it claimed the C of G was around waist height.
KENAT,
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RE: Ergonomics Standards - CoG Human Body
Just as a thought, I'm pretty sure Mark's Mechanical Engineering Handbook has a human ergonomics section with measurements and such.
Other places to try might be a search on "Human Factors in Engineering", very common in Universities, and even look within the fields of medicine.
If you go to www.3dcontentcentral.com , you should be able to find some dummy models. However, I'm not sure of their accuracy.
Best of luck.
Kyle Chandler
www.chiefengineering.net
"To the Pessimist, the glass is half-empty. To the Optimist, the glass is half-full. To the Engineer, the glass is twice as large as it needs to be!"
RE: Ergonomics Standards - CoG Human Body
I'm not sure what you're looking for. I don't think you're going to find a reliable universal formula or table. It's like asking, "What is the center of gravity of a vegetable?"
Don
Kansas City
RE: Ergonomics Standards - CoG Human Body
RE: Ergonomics Standards - CoG Human Body
RE: Ergonomics Standards - CoG Human Body
I'd look at using a uniform density and estimate volume of various parts as btrue says.
You may be able to find typical mass values for some body parts, after all "the human head weighs 7 pounds" or whatever the kid in that movie said.
Are you also considering moment of inertia, now that could be fun.
KENAT,
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RE: Ergonomics Standards - CoG Human Body
Cheers
Greg Locock
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RE: Ergonomics Standards - CoG Human Body
The 1.015 is the value from the Navy paper in the "volume of a human being" thread, error is within 1%...so, you could use anything from 1.005 to 1.025, but no, not 1.000, not unless you want to be laughed at.
...
:P
RE: Ergonomics Standards - CoG Human Body
http:
RE: Ergonomics Standards - CoG Human Body
http://www.dentonatd.com/wwregulations.html
h
far too much for me to wade through there, but it beats chopping up your least favourite co-worker and weighing him.
Cheers
Greg Locock
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RE: Ergonomics Standards - CoG Human Body
That's actually darn good thinking on the test dummies Greg, perhaps star worthy.
KENAT,
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RE: Ergonomics Standards - CoG Human Body
ht
Also, you could easily estimate mass and cg and moments of inertia for each limb, assuming it is a uniform cylinder, I doubt you'd be enough in error to matter, given that you know the total mass, and the cg location of a standing adult (roughly the bladder).
Cheers
Greg Locock
SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.
RE: Ergonomics Standards - CoG Human Body
I have an understanding that the values will be different, dependant if the data is male or female. I am going to use the higher percentile values so that my final answer will be pessimistic.
The reason for this is finding all the information is that if I know the length and mass of the limbs and I also know the position of the centre's of gravity of each component. I can build up a stick model to estimate the CoG (from data I have found stood upright with arms down the CoG is just above your naval in the mid plane of your torso).
Now that I know the 'stood upright' CoG if I start adding the range of movements of your joints, knee's, hips and arms I can manipulate the model into the position I require and then calculate the new CoG........ That's the plan anyway.
At the moment I am not considering moments of inertia, but may have to consider it later on
I will search the crash test stuff to see if I can glean any information off them
Again, many thanks for people's response's.
RE: Ergonomics Standards - CoG Human Body
http://
http://www.openerg.com/psz/anthropometry_data.html
http://msis.jsc.nasa.gov/sections/section03.htm
ht
Cheers
No more things should be presumed to exist than are absolutely necessary - William of Occam
RE: Ergonomics Standards - CoG Human Body
BS EN ISO 15535:2006 General requirements for establishing anthropometric databases
BS EN 614-1:2006 Safety of machinery. Ergonomic design principles. Terminology and general principles
BS EN ISO 6385:2004 Ergonomic principles in the design of work systems
cheers
No more things should be presumed to exist than are absolutely necessary - William of Occam
RE: Ergonomics Standards - CoG Human Body
If first you do succeed...try something harder.
Blair H.
SW 2008 sp2.0, HP x6400, 2.0ghz dual core xeon, 2.0 GB ram, Nvidia Quadro FX 1500
RE: Ergonomics Standards - CoG Human Body
You can also discuss your idea with your doctor on your next physical and he may be able to guide you in the right direction.
RE: Ergonomics Standards - CoG Human Body
I have looked mainly at the Nasa link (third one down on HamishMcTavish list of links) and tried to reference all my information from that research. However, bits of critical information are missing so I am going to make some assumptions with certain parameters.
I will check the BSI standards as well.
Again many thanks to all who have helped me.