Page 1 of 1

how i can get net axial knee force from inverse dynamics?

Posted: Sun Feb 24, 2019 1:45 am
by cuiweiling
hi,
how i can get net axial knee force from inverse dynamics?
thanks

Re: how i can get net axial knee force from inverse dynamics?

Posted: Sun Feb 24, 2019 10:43 am
by mitkof6
You can get this through joint reaction analysis if the knee is not permitted to translate in the axial direction:

https://simtk-confluence.stanford.edu/d ... s+Analysis

Re: how i can get net axial knee force from inverse dynamics?

Posted: Fri Mar 08, 2019 7:19 am
by cuiweiling
Thank you very much for your guidance and I want to ask some questions further.
1. I used ID results to calculate net axial force of the tibia through joint reaction analysis and specified Joint_name: knee, apply_on_bodys: parent and expressed_in_frame:child, correctly?
2.If 1 is accepted, the net axial force ranges from 4000 to100000N and obviously wrong, why?
3.Does actuator part of analyze tool has to set file? if need,Is there anything I need to pay attention to?
thakns angin.

Re: how i can get net axial knee force from inverse dynamics?

Posted: Tue Mar 12, 2019 2:36 am
by mitkof6
Hi,

1. No need to use the results from ID. You have to perform IK and SO. The following webinar might answer your questions better:

https://www.youtube.com/watch?v=ly4rhOOifO0

2. No, they are not accepted. Probably you are not applying the muscle forces (as computed from SO) in the JR analysis.

3. Do not set any reserve actuator file!