Modifying servo wall fix.

Submitted by rsharma on Sat, 04/10/2021 - 08:15

Is there any way to modify the servo wall fix from:

fix servo all mesh/surface/stress/servo file plate.stl type 1 com 0. 0. 0. ctrlPV force axis 0. 0. 1. target_val 10 vel_max 1. kp 5.

to:

fix servo all mesh/surface/stress/servo file plate.stl type 1 com 0. 0. 0. ctrlPV torque axis 0. 0. 1. target_val 10 vel_max 1. ratio 0.01 mode auto

in between two runs?

Forums:

mschramm | Sun, 04/11/2021 - 20:23

Hello,
Unfortunately, you cannot switch from PID to auto using a fix_modify command.
You will have to get the current height of your wall, unfix the servo wall then apply a new fix with the auto scheme in the old spot of the last wall.

If you only wanted to switch from a ctrlPV force to ctrlPV torque, you could do this with the fix_modify command.

You may be able to add to the modify_param function to do what you wish but it is not ready made to do this.

kardous | Mon, 04/12/2021 - 11:10

Hello everyone,
I got this error when running my simulation that I don't undrestand very much:
ERROR: Mesh (id Drum): 364 mesh elements have been lost / left the domain.
Please use 'boundary m m m' or scale/translate/rotate the mesh or change its dynamics
FYI: center of mass of mesh including scale/tranlate/rotate before cutting out elements is 0.000681 / 0.000072 / 0.021000
simulation box x from -0.050000 to 0.050000 y from -0.200000 to 0.200000 z from -0.200000 to 0.200000
center of mass of mesh after cutting out elements outside simulation box is is 0.003209 / -0.006346 / 0.021000
(gives indication about changes in scale/tranlate/rotate necessary to make simulation run)
(/build/liggghts-YO7u74/liggghts-3.8.0+repack1/src/multi_node_mesh_parallel_I.h:605)

Anyone can help to fix it please. i guess it's a problem with the boundary limits of the simulation. I am simulating a rotating drum of 30 cm and a thikness of 4.2 cm. That's why I chose the boundaries like this: (in meter)
#Definition of boundaries
variable xmin equal -0.05
variable xmax equal 0.05
variable ymin equal -0.2
variable ymax equal 0.2

variable zmin equal -0.2
variable zmax equal 0.2

In advance thank you so much for your help,
Best Regards,
S.Kardous

wangxiukai | Thu, 05/06/2021 - 16:33

ERROR: Mesh (id Drum): 364 mesh elements have been lost / left the domain.

From my point of view, the wall is moved out the domain during the servo process.