simtk.org

I'm trying to run the ID. It appears to be running okay, but instead of having joint moments in the output every row is filled with junk like

1.#QNAN0000000000000

I have browsed the forum and seen other people have had this same issue. Some of the responses suggest there may be an error in the model regarding mass or moment of inertia properties. I've checked through each segment and the parameters in the model are all similar to the gait2354 parameters.

When I try to use the gait2354 model which comes with Open SIM and plug in my data I get similar nonsensical results. However, when using the examples that come with Open SIM and the gait2354 model the ID analysis appears to work fine. The IK works fine with both models and data sets so it doesn't appear to be an issue with the actual motion data.

So at this point I'm stuck. If anyone who has dealt with this problem could suggest where I might look next for troubleshooting it would be greatly appreciated.

Thanks,

- Jim

Jim,

Since the gait2354 model (I assume you're using the version scaled for your subject) leads to nonsensical results too I'd assume it's the data. I'd first try running inverse dynamics without external/GRF forces and see if that works (leads to reasonable answers) then we can zone in more on the problem.

Please let us know how that goes,

Good luck
-Ayman

I am having a similar issue. If I run the data without external forces, the Inverse Dynamics analysis works. Adding External GRF causes a breakdown.

I posted a bug report yesterday along with sample files. If the issue is the external force file, any insight woudl be great.
John

John,

Since I couldn't find your setup file I created one live from the GUI, and had no problem running it (after I changed the absolute path for your grf file to match mine. I assumed no filtering, and the results were reasonable.
When I filtered the external point kinematics I got a couple assertions (in my debuggable build) when running with start time of exactly 0. but run successfully when I ignored those and the results were ok. Can you please post the setup file you're using to the bug report? Could also be an issue with the file specification for grf (what os are you running?)

Cheers,
-Ayman

Hi Ayman,
I posted a new zip file in the bug report. This one has all of the original files and the ID setup file. I ran this prior to submission and OS crashed.

I am running OS 2.2.0_b1