COP calculation

[longbin]

Hi

I was wondering if there is any function in Anybody script that we can use to calculate the COP? I try to search on the forum, it seems that I found some related but old answers several years ago. I still don't know how to do it. I would really appreciate it if someone could give me some hit. Thanks a lot in advance.

Best
longbin

[longbin]

Hi again

I found where is the COP, but it seems in the local coordinate system of FP, right? How can I turn it on and get the coordinate in the global coordinate system?

By the way, if i want to know the knee joint center in the global system, is it to multiply Axes? "AnyVec3 sRel2= sRel*.KneeJoint.Axes;"

Thanks

Best
longbin

[toerholm (Søren Tørholm)]

Hi Longbin,

We do not have a system function for this, but you can look in the Forceplate classes and GRF prediction examples to see sample codes...

It use forcemoment measures to summarize forces into a F and M and then calculate CoP based on F and M and yes i think this is in the FP system.

To get it into global you will need something in this line.

CoPGlobal =FP.r+ CoPLocal*FP.Axes;

Please try to draw it in global coordinates and double check you get the same location as displayed using local frame.

The knee joint location in global coordinates is defined by the "r" property and "Axes" is knee axis orientation in global system.

Best regards
Søren

Best regards
Søren