What's the meaning of this- FLocal = F * HumRef.Axes?

[Taejun (MA Taejun)]

Hi,

I am studying the example (StairAssist_Exo-main) of the last seminar. In the Fotce_left.any.

What's the physical meaning of this-HumRef.Axes? Where is the value of M? What's the physical meaning of the result of F*HumRef.Axes?

Thanks,

TJ

[pgalibarov]

Hello TJ,

Please check reference manual to learn about AnyForceMomentMeasure2, which has an output member M - in short it a computed equivalent moment in global coordinates. Same with Axes - it is an orientation of a ref. frame in global. Flocal, as the name suggests, is a recomputed value of the force in the local coordinate system.

Kind regards,
Pavel

[Taejun (MA Taejun)]

Hi,

thanks for kind explanation, do you mean that if F= Fall, then Fx, Fy, and Fz should be the local force? Thanks!

Best,

TJ

[pgalibarov]

No, the global reference frame (coordinate system) is the frame in which your entire model is defined.
The local one could be a node on a, say, arm, moving wrt global ref. frame. If your need the forces to be expressed in the ref. frame (coordinate system) of the node on the arm, for example, to align an external force with the axis of the forearm - you would apply the force in the local nodal coordinate system.

According to the ref. manual on AnyForceMomentMeasure2:
M - Equivalent point moment/torque vector in global coordinates.

Kind regards,
Pavel

[Taejun (MA Taejun)]

So what you said is that this function could transform the computed equivalent force from one reference coordinate system to another one? Thanks!

Best,

TJ

[pgalibarov]

Yes, it does for the specified list of force objects.

P.

[Taejun (MA Taejun)]

Great, thanks for your help！

Best，

TJ