GRF prediction

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1

Dear AnyBody community,
The grf prediction programme help me a lot and I know how to use it .But I want to know more about the process of calculating the GRFs&GRMs in the GRF predictions files. I open the file “ContactSurfaceDistanceAndVelocityDepLinPush.any” and got the details about calculating the GRFs.However,I can’t obtain the process of calculating the GRMs.Could you give me more detailed information about GRMs ?

Thanks!

Best regards,
Tiger

2

Hi Tiger,

I am sorry but i assume that by GRF you mean moments right?

Here is what the wiki says :

GRF prediction relies on conditional contacts added to the feet of the model. The conditional contacts work as force actuators to generate the normal and frictional forces necessary to balance model. Mathematically, the actuators are modeled similarly to muscles, and the muscle recruitment optimization determines the contact forces. The effect is that the model will utilize the ground reactions if that can minimize the muscle activity

The GRF forces simultaneously also creates a moments since they act on many points and all have friction as a posibility so the GRM are also found implicitly..it comes out of the way the GRF are predicted.

Best regards
Søren