Hi all,
Besides the joint moments output in inverse dynamics I would also like to look at the body forces at the joints, but when I perform the simulation the outputs in the bodyforces file are all zero in FX,FY,FZ. Is there anyone who had the same problem?
Really appreciate any help.
Body forces at joints
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Maud Hendriksen
- Posts: 20
- Joined: Thu May 14, 2020 12:00 am
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Jacob J. Banks
- Posts: 88
- Joined: Tue Jul 15, 2014 5:17 am
Re: Body forces at joints
I've actually recently had this same question.
A work-around I found that seems to 'sort of' work is to take a SOpt output force file that matches your model and trial of interest and input all 0's into it and then run the JRR tool with that file. This 'seems' to give pretty decent body force estimates. However, an issue I have with the results is that the feet/ankle forces don't seem to be as close to the GRF forces as I would like. Only thing I can think is that JRR (&SOpt) doesn't seem to solve joint moments (viewtopicPhpbb.php?f=91&t=11025&p=30580&start=0&view=) from a traditional top-down and bottom-up approach but rather a combo (similar to RRA)... but I have not had confirmation on this (just my observations of things).
Will be interested to see if there is a better solution and/or if there is something wrong with my approach (or with the latter, if you have better luck with it).
Jake Banks
A work-around I found that seems to 'sort of' work is to take a SOpt output force file that matches your model and trial of interest and input all 0's into it and then run the JRR tool with that file. This 'seems' to give pretty decent body force estimates. However, an issue I have with the results is that the feet/ankle forces don't seem to be as close to the GRF forces as I would like. Only thing I can think is that JRR (&SOpt) doesn't seem to solve joint moments (viewtopicPhpbb.php?f=91&t=11025&p=30580&start=0&view=) from a traditional top-down and bottom-up approach but rather a combo (similar to RRA)... but I have not had confirmation on this (just my observations of things).
Will be interested to see if there is a better solution and/or if there is something wrong with my approach (or with the latter, if you have better luck with it).
Jake Banks