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External load on hand

Posted: Wed Aug 24, 2011 3:46 am
by martam
Hi everyone!

How can I apply an external load on the model's hand, for the inverse dynamic analysis?!Should I include it in the same *.mot file as the ground reaction forces or should I write a new one just for the hand?

Thanks,
Marta

RE: External load on hand

Posted: Wed Aug 24, 2011 4:53 am
by rudi
Hey Marta,

I've been adding additional external loads by including them in the same .mot file as ground forces. In that case, you need to add all forces as external loads in the ID dialog box creating .xml file. So, I don't know if you can do that by appending the external loads to the model.

Hope that helps,

Rudi

RE: External load on hand

Posted: Fri Sep 02, 2011 9:36 am
by martam
Thanks for your answer Rudolf!

Once you added the extra forces, were you able to visualized them all in the GUI, with the "preview motion data" option?

Because I can't, and I don't know if I'm doing it the wrong way or if it's no possible!

Re: External load on hand

Posted: Fri Sep 02, 2011 9:57 pm
by rudi
Hi Marta -

I didn't even try to visualize the forces, and today my OpenSim seems to have a bad day so it doesn't do anything. It may be that you can visualize only two forces. However, I was able to plot all forces in Preview Motion Data. Then, I used ForceReporter in Analyze tool to make sure OpenSim had applied the forces correctly. Can you do that, or is your problem just visualization?

Let me know if you haven't been able to create a correct .mot file.

Rudi

Re: External load on hand

Posted: Sat Sep 03, 2011 6:20 am
by martam
I can plot all the forces, and managed to run ID with the file created. however, when I tried to run a ForceReporter analysis and a Bodykinematics analysis, an error ocurred, with this message:

"XMLDocument.XMLDocument: ERROR- SAX exception while attempting to parse C:\Users\Marta\Documents\IST\Tese\OpenSim\Analises\Files\Direita\Dir_grf.mot
SAXException message = Invalid document structure"

Dont know why!

Re: External load on hand

Posted: Sat Sep 03, 2011 6:23 am
by martam
Never mind...figured it out!
I had a thing wrong in the xml settings file!I worked now

Re: External load on hand

Posted: Sat Sep 03, 2011 8:16 am
by martam
I've performed an analysis, with ForceReporter..and although my .mot file has 3 external forces only 2 external forces appear in the ForceReporter!!

Any explanation for this?

Re: External load on hand

Posted: Sat Sep 03, 2011 9:20 am
by rudi
How did you add the forces? When adding external load file, say, in ID tool i click first the right-hand side button of the external loads drop-down window. In the opening window I load my .mot file and use it to create external loads one by one. Then I save that file as .xml file. Do you follow? When re-doing analyses I click the left-hand side button of the drop-down window to choose the .xml file. And when running Analyze tool you need to include the .xml file of your forces as well.

Let me know if you need further help. Good luck!

Rudi

Re: External load on hand

Posted: Sun Sep 04, 2011 6:40 am
by martam
I've tried that, and nothing!
I'll try it again, and see how it goes!

Thanks

Re: External load on hand

Posted: Sun Sep 04, 2011 9:43 am
by martam
Still nothing!
I've created the .xml file as you said, performed ID and then Analyze tool to Report forces, and still only two external forces appear in the Force Reporter, dont know what else to do!!

Any idea how to solve it?Can I send you my .mot file so you can see if something is no right