RRA residuals problems across passages

[Rodrigo Mateus]

Hi there,

I am trying to correct some athletes performing an abrupt single limb horizontal deceleration task, and I came across some problems while performing the residual reduction algorithm.

I cannot seem to make the center of mass displacements converge, as well as achieving a reccomended total mass change low enough to have confidence in the results.

I usually make several passages (around 5 to 10) to achieve the wanted results. However, in certain cases, the FY MZ residuals (the ones responsible for the calculations the mass changes and COM displacements, respectively) always increase after each passage.

First passage:

Mass Adjustments.txt

(2.06 KiB) Downloaded 15 times

Second passage:

Mass Adjustments.txt

(2.06 KiB) Downloaded 10 times

Third passage:

Mass Adjustments.txt

(2.06 KiB) Downloaded 7 times

The respective optimal forces are: FY, 6N and MZ, 6Nm. The subject has a mass of 70.5 Kg. The GRF have these curves.

image.png (33.81 KiB) Viewed 233 times

Can anyone with expertise in this area or if you have encountered this same situation help me? What could be the best approach in this case?

Best regards,

Rodrigo Mateus

[jimmy d]

Hi-

If you are not modeling the entire system (all forces and all bodies that are accelerating), there will be errors (residuals). It is not possible to answer your question without knowing more about your system (model and forces). If you can give further details then perhaps we can give you better answers.

[Rodrigo Mateus]

I cannot give all the details I want, because there is a size limit in the attachments I can upload.
Can you give me your email so that I can send you all the data details?