External load on hand

Rudolf Klemetti · Post by **Rudolf Klemetti** » Sun Sep 04, 2011 10:14 am

Sure, you can send your .mot file to me. I will check it out. What version of OpenSim are you using? In old versions you can apply only two forces.

Marta Meneses · Post by **Marta Meneses** » Sun Sep 04, 2011 10:28 am

I'm using OpenSim2.2.1!I cant upload it here,can you send me your e-mail,please?
Thanks

Jesse Garnier · Post by **Jesse Garnier** » Tue Sep 06, 2011 11:03 am

I have adjusted the forum settings so that .mot files can now be attached to discussion posts or private messages.

Filippo Soremic · Post by **Filippo Soremic** » Wed Oct 24, 2012 6:47 am

Hi, my name is Filippo and I am a new beginner user.
I'm try to use the model arm26 to performe a joint reactions analysis.
I edit the model as the sample adding the bucket and load the motion loaded by jessegarnier.
The guide cite 4 file as input to perform the joint reaction analysis with a generic model.
Are they available on-line for arm26 and arm26+bucket?

PS : are some user in Italy available to meet for sharing live problems/results?

Thanks to all,
Filippo

Ayman Habib · Post by **Ayman Habib** » Wed Oct 24, 2012 10:05 am

Hi Filippo,

Attached is a zip file that contains a model (free block), a file containing forces to apply to the block .sto, an ExternalLoads file and a setup file to run the forward tool applying the force specified in the file to the block. This should serve as an example for applying an external load to the hand.

Hope this helps and please let me know if you have any questions.

Best regards,
-Ayman

Filippo Soremic · Post by **Filippo Soremic** » Thu Oct 25, 2012 7:00 am

Hi Ayman,
thahnks for posting the example, I'm trying to run it, but, sorry, I have a lot of doubt.
I list my questions (many,sorry, if there is answers on the site I don't found them, but you may post the links)

1 - Loading bolck.osim the 2 bodies didn't appear on my pc. I think it is because the relative .vtp images are not in the folder "geometry".I don't found the images on the site, so I change the .vtp : ground --> arm_r_humerus and block --> arm_r_ulna.
Orrible, but it works...how can I dispay the original figures of the example?

2 - Now, have I understand the function of each files in the folder that you posted? (Correct me if I'm wrong...)
PointForceAlongY.sto : ok, you explain
blockExternalForces_noTorque.xml : translate the external forces to pass them to OpenSim
setup_Forward_noTorque.xml : tell to OpenSim the total situation to run the analysis

3 - Then I run the Analysis with those settings:
(Tool --> forward dynamic)
Input in Main Setting : setup_Forward_noTorque.xml
I specified the external Load in the window "Actuator and external load":
blockExternalForces_noTorque.xml
I enable "Joint reaction" in the window "Analysis"
Are all that steps right?
Why I'm using the forward dynamic instead Inv Din? I'm searching JointReactions imposing External Loads...

Thank you,
Filippo

Ayman Habib · Post by **Ayman Habib** » Thu Oct 25, 2012 12:47 pm

Hi Filippo,

1. The file block.vtp should be in the latest distribution under Geometry, so if your Geometry Path points there (installDir/Geometry) then you should see it in the GUI, but your workaround is ok for now.
2. Your understanding is correct, the only reason I provided a Forward simulation setup file is so that you can run it and see that the force is actually applied, but the same ExternalForces file can be used by any other tool: InverseDynamicsTool in your case, AnalyzeTool (to compute JointReactions or run any other analysis).
3. Again, in your case you'd use Tools->Inverse Dynamics and then populate the dialog that comes up.

Hope this helps and please let me know if you continue to have questions.

Best regards,
-Ayman

Filippo Soremic · Post by **Filippo Soremic** » Tue Oct 30, 2012 9:42 am

Hi Ayman, thanks for all yours helps.

I'm now trying to visualize the joint reaction on the GUI, like green arrows in the sample of the gait, but I can Not.
Is there something to do after run the Joint-reactions analysis weith the tool?
OpenSim create the file with the JointReactions (I think), but I can't see them anywere.

Thanks, regards.
Filippo

Ayman Habib · Post by **Ayman Habib** » Tue Oct 30, 2012 10:26 am

Hi Filippo,

To visualize analysis results you need to tell OpenSim what to draw and in what frame etc. This is documented on the support site page here
http://simtk-confluence.stanford.edu:80 ... h+a+Motion

Please give it a spin and let us know how it works for you.

Best regards,
-Ayman

Filippo Soremic · Post by **Filippo Soremic** » Sat Nov 03, 2012 6:28 am

Hi, Ayman.
I gave a spin to the document you suggest,thanks.
Now I'm trying to use the model arm26 with bucket to perform an ID analysis.
May I use the mass of the bucket as external force?
How can I specify to use the bucket as external force?

Else, is the way to specify external force the same file use in the free block?
Because I can manipulate the external force applied to the free block, but I can not do the same for the arm...

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