Adams assembly CoG Calculation

Question

Adams assembly CoG Calculation

Vojtech Brychta (Automotive)

(OP)

23 May 22 09:00

Hello gentlemen,

I'd like to ask you for a tip or trick on how to calculate the CoG position for the assembly created in A/View. The goal is to get continuous measurement during a simulation. I have multiple parts in my models and I don't want to go through them one by one.

Thank you for your tips.

Edit: I noticed a thread here asking the same question, but without an answer.

GregLocock (Automotive) · Answer 1 · 2022-05-23 21:58:08

That's a fun one. So each PART has a cg marker and a mass. Plot the location of each cg marker over time, then take the weighted average of x y z. So if you have two parts

CGX(t)=(cg1x(t)*m1+cg2x(t)*m2)/(m1+m2)
and so on for y and z

That seems like an amazingly useless piece of information, but doubtless you have your reasons.

Cheers

Greg Locock

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Vojtech Brychta (Automotive) · Answer 2 · 2022-05-24 05:24:22

Hello Greg,

thank you for the reply. This is the approach I'm trying to avoid as I have multiple parts in my model. Maybe there is a way to automate it? How do I list all the parts I use?

Yes I have my reasons why I need it and I guess I'm not the only one since I found another post asking the same question. I hoped there might be a trick on how to obtain the results without going from one part to another.

Thanks.
VB.

GregLocock (Automotive) · Answer 3 · 2022-05-24 08:59:18

OK, to find a list of all your parts export an adm file, and do a search for PART/ each part will be found.

I tend to do any postprocessing in Matlab or Octave or Hypergraph. So I would build a request statement to report the location of each cg marker, and then export all those requests and read them into Matlab. I don't actually use View so I can't go into any detail on that process. I've got a proprietary file converter that grabs a req file and turns it into an ascii file, and would swear blind that there was one on the Matlab file exchange but haven't been able to find it recently. here's a discussion, i don't know how useful https://comp.soft-sys.matlab.narkive.com/XPeu9Am3/...

In vehicle models we just slam a marker in at the CG of the body and use that.

Cheers

Greg Locock

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Adams assembly CoG Calculation