simtk.org

Hello,

I am hoping to learn more about some values in the output, specifically avg residual torque. Here is a sample output:

Avg Marker RMSE: 1.4794449150739888cm
Avg Residual Force: 0.0022730949786689716 N (0.00043452956222329636% of original 523.1163023842488 N)
Avg Residual Torque: 6554.3892527295775 Nm (100.34002107112094% of original 6532.17846952995

Does the avg residual force look a bit high? What is the best way to interpret this?

Thanks!

Hi Alex,

The average residual force looks file, but the residual torques look very high. I would take a look at the centers of pressure: bad COPs are usually the problem when residual torques are large.

-Nick

How is the original torque calculated? In my trials I have an original force but the original torque says 0.0Nm

Hi Duncan,

The original torques (and forces) are calculated by running inverse dynamics on the kinematics from the marker fitting step with the GRFs applied. If the original torques are exactly zero, then something is likely wrong with the input data.

If you provide a screenshot or error message, I can help debug further.

-Nick

Hi Nicholas,

It doesn't generate an error, but the log shows:

Avg Marker RMSE: 2.297358580624706cm
Avg Residual Force: 46.69737107660755 N (5.838317793768835% of original 799.8429123958804 N)
Avg Residual Torque: 21.96351022960977 Nm (100.0% of original 0.0 Nm)
Avg CoP movement in 'perfect' GRFs: 0.025545413251444483 m
Avg force change in 'perfect' GRFs: 16.266117168322367 N

I am using a custom model with the foot bodies defined as R_Foot and L_Foot

Thanks,
Duncan