help with RRA

Andrea Morelli · Post by **Andrea Morelli** » Thu Oct 29, 2009 1:21 pm

I've go trought scaling and inverse kinematics of a gait analisys test. During RRA the process, after about 1 second on wich i see the model "walking" like in IK the process became very slow and the model start to "fall" moving in the -Y direction....
I've used Gait2392 model adapted for a Davis protocol. I made changes to RRA_Actuator.xml file to reflect pelvis mass center after scaling but nothing change.
Some one can help me ?

Thank you
Andrea

Ayman Habib · Post by **Ayman Habib** » Mon Nov 02, 2009 4:34 pm

Hi Andrea,

As a first step, can you check the Wiki page below:

http://wiki.simtk.org/opensim/rraCmcPage

I'd particularly check that GRF are applied ( to the correct segment). I'd also check that
residuals at pelvis are applied correctly.

-Ayman

Gaurav Mukherjee · Post by **Gaurav Mukherjee** » Thu Mar 14, 2013 4:54 pm

Did you find a solution to your problem Andrea? Could you please update the conversation? I'm facing the same issue albeit with a lift task. Thanks!

Peter Martindale · Post by **Peter Martindale** » Sun Mar 17, 2013 11:37 am

Hi Andrea,
I had this problem with a model I am working on and found it was due to the application of the GRF data. I only have GRF's for a portion of the motion data (two force plates in the middle of the lab) so I run RRA for a time interval that I have the GRF's for. Specifically, I run RRA from when the right foot is on the right force-plate and left foot has left the ground, until the left foot is on the left force-plate and the right foot has left the right force-plate.

help with RRA

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