RRA mass recomendation

[ANDREW LAPRE]

Hi, I am going through the tutorials for using RRA and it says "adjust the mass as recommended by the RRA Tool". I see that after I run the tool, the CoM changes, but I need to change the mass manually. The problem is that I don't know where this recommendation is. I've gone through the output files, but don't see anything. Any help would be appreciated!!

Thanks
Andy

[Brian Umberger]

Hi Andy,

You should find the recommended mass changes in the Messages window in the GUI (not in the output files). I just ran RRA on a model and this is what was in the Messages window. Hope this helps,

Brian


************************************************************
* Summary of Mass Adjustments to Reduce Residuals *
************************************************************
* Body adjusted: torso
* Mass Center (COM) adjustment: dx =-0.0220163, dz =-0.0341405
* New COM location: ~[-0.0103753,0.34551,0.0341405]
************************************************************
* Recommended mass adjustments:
* Total mass change: 0.00962877
* ground: orig mass = 0, new mass = 0
* pelvis: orig mass = 11.3752, new mass = 11.3767
* femur_r: orig mass = 8.98404, new mass = 8.98523
* tibia_r: orig mass = 3.581, new mass = 3.58148
* talus_r: orig mass = 0.096588, new mass = 0.0966008
* calcn_r: orig mass = 1.20735, new mass = 1.20751
* toes_r: orig mass = 0.20921, new mass = 0.209237
* femur_l: orig mass = 8.98404, new mass = 8.98523
* tibia_l: orig mass = 3.581, new mass = 3.58148
* talus_l: orig mass = 0.096588, new mass = 0.0966008
* calcn_l: orig mass = 1.20735, new mass = 1.20751
* toes_l: orig mass = 0.20921, new mass = 0.209237
* torso: orig mass = 33.0685, new mass = 33.0728
************************************************************
* Note: Edit the model to make recommended adjustments to *
* mass properties. *
************************************************************

[ANDREW LAPRE]

Great, thanks a lot Brian!

[Ross Miller]

Bumping this thread for a related question:

Is there a setting that can be enabled to tell RRA "Go ahead and apply these suggested mass changes to the current model" rather than the user manually entering them? I realize I could probably write a script or something to do this, but it seemed like a case where I may just not have the right flag checked.

Ross

[Josh Baxter]

I don't think this feature has been added - at least it doesn't show up in the API docs and a recent post suggests this feature isn't available...
viewtopicPhpbb.php?f=91&t=7430&p=19634& ... 03593dc4a0

i'd recommend running the RRA tool using the command line call thru MATLAB's dos function. the returned variable is the message output which could be parsed and used to update the model... but an automatically updated model would be great in a future release.

[Ross Miller]

Thanks Josh. I have run quite a few simulations with the mass of the patella set to 0.97 instead of 0.097 =)

[Josh Baxter]

I just put this matlab call together. it seems to do the trick... it uses model and other files from the gait10dof folder

*edit* i'm having trouble uploading attachements. PM if you'd like these matlab scripts.

[Josh Baxter]

Here is a set of files that run rra, update the mass properties, and write a new osim model.

Main_rra.m sets up a Params structure that is passed along to runrra.m to setup and run the rratool thru the command line. Runrra also updates the model's COM position on the user defined segment. Then main_rra.m parses the rra output text and those mass values are used to update the _adjusted.osim file. The main action happens in main_rra.m lines 37 -64. This was developed for osim 3.3 but confirmed on osim 4.0.

main_rra.zip

matlab and osim files - rra auto mass adjustment

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