Huge RRA

Provide easy-to-use, extensible software for modeling, simulating, controlling, and analyzing the neuromusculoskeletal system.
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Jonathan Bulluck
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Joined: Mon Sep 01, 2008 4:29 pm

Huge RRA

Post by Jonathan Bulluck » Wed Feb 11, 2009 1:02 pm

I'm doing a study on single-leg landing and we're using the 2392 model with varus/valgus and when we do the simulation in OpenSim, the RRA is as big as 3000 to -3000. When graphing the RRA it looks like a sine wave. Is there a way to get the RRA low and not have it look like a sine wave. We start the simulation in "mid-air" since the person is landing from a certain height on to a force plate and not the usual gait simulation. Thank You.

Jonathan M. Bulluck
East Carolina University
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Sam Hamner
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Joined: Tue Jun 26, 2007 5:03 pm

RE: Huge RRA

Post by Sam Hamner » Wed Feb 11, 2009 5:45 pm

Hi Jonathan,

Sounds like you're running RRA without proper ground reaction forces (GRFs). Are you inputing the external loads in the RRA (or CMC tool)? Or, it could be that your GRFs are not being read incorrectly (i.e., they have the wrong coordinate system, or have the wrong units). Did you visualize the GRFs with your IK solution?

Cheers,
Sam
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Nicolas Schwenck
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Joined: Fri Aug 15, 2008 5:29 am

RE: Huge RRA

Post by Nicolas Schwenck » Mon Jun 08, 2009 9:21 am

Have you managed to simulate your problem correctly?

I'm in general interested if it is possible to use CMC to compute muscle force distributions for motions(or at least with long periods) without ground reaction forces? Anyone?
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