CMC - Extreme difficulty resolving reserves problems

[Rodrigo Mateus]

Hi,

I am working with the model gait 2392 to estimate muscle forces in an abrupt deceleration movement.

After performing CMC, I got the values for the reserves and they were extremely high. I followed the pipeline given in this site: https://simtk-confluence.stanford.edu/d ... d+with+CMC for troubleshooting tips, and after observing the resulting kinematics after CMC, I noted that there is an unexpected change in the kinematics around 0.348 s that coincides with the appearance of reserves.

reservesCMC.png (43.63 KiB) Viewed 500 times

Kinematics CMC.png (37.64 KiB) Viewed 500 times

Could this be because I only adjusted the maximum isometric forces of the muscles and not their optimal fiber length and tendon slack length?
I already tried to adjust the tracking weights of the reserves which shown this issue without any success. I also tried to increase the control constraints of residuals but did nothing. I also tried to adjust the tendon slack length of the muscle that weren't operating in the ideal region of normalized fiber length, and got no success either. I also increased the FmaxMuscleStrain value in the antagonist muscles of the problematic degrees of freedom but did nothing either.

What should I do next?

Thank you in advance,

Rodrigo Mateus

[Thomas Uchida]

What is happening at 0.348 s? What is your strategy for preprocessing (e.g., filtering) kinematics and GRFs for this abrupt movement?

[Rodrigo Mateus]

This is the unexpected motion.

results2.7z

(698.47 KiB) Downloaded 7 times

They were low pass filtered with a 4th order 8 Hz Butterworth filter.

I used the unfiltered kinematic data from RRA for CMC. The strange was not present in the kinematic data from RRA. For performing RRA, I filtered the original kinematic data at 6Hz, the default value.

[Thomas Uchida]

They were low pass filtered with a 4th order 8 Hz Butterworth filter.

What is the frequency content of your "abrupt movement"? You might want to plot the filtered kinematics and GRFs to ensure they are representative of the motion. Also see Adrian's comments on this recent post (topic 9441): viewtopicPhpbb.php?f=91&t=9441.

[Rodrigo Mateus]

Firstly, I am sorry for the late reply.

Unfortunately, I do not understand the question.
But thank you for the advice, I read the topic and it was very helpful!