What is the meaning of keyword com in servo command?

Submitted by wangxiukai on Sun, 03/21/2021 - 08:06

Hello,

I am a beginner of LIGGGHTS. I am troubled by the meaning and effect of the keyword com in servo command
eg:
fix x0 all mesh/surface/stress/servo file meshes/x_0.stl type 1 scale 1 com 0.5 0.5 0.5 ctrlPV force axis 1.0 0.0 0.0 target_val 5e4 vel_max 1

In the document, the com was described as the center of mass. I do not understand what it does. I try to change its value, but it seems to get
the same result.

Can anyone help me?

Thank you!

Wang Xiukai

Thao | Mon, 04/25/2022 - 13:12

HI guys,

On a related topic about the meaning of terms used in the servo wall, do you know how to get an appropriate value for vel_max and kp? Anytime that I changed these values, my servo_wall forces change significantly although the target_force applied is the same. I have no idea why is that?

Thanks so much.
Thao