Variable conveyor speed

Submitted by RocheDEM on Thu, 08/08/2013 - 16:15

Is there a simple way to change the speed of a conveyor (surface velocity).

The only thing I can think of is to start with one fix mesh/surface with a certain surface velocity. stop the simulation and write a restart file.
Restart the sim with a new surface velocity...

I'm sure there is a better way though.

Thank you for your help,

Kirk

Forums:

RocheDEM | Thu, 08/08/2013 - 19:30

Unfortunately I am having trouble with the restarting concept.

Does anyone have an idea how I can do this in the same run? Maybe fixing and unfixing two different conveyors!?

Kirk

Kirk A. Fraser, ing. P.Eng.
Ingénieur en Conception
Design Engineer
________________________________________
kirk.fraser@roche.ca

Tél. : 418.549.6472 Poste : 263
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ckloss_ | Sat, 08/10/2013 - 00:05

Yes unfixing and re-fixing would be a kind of work-around.

Alternatively, we could implement a variable feature for the conveyor velocity. Contact me via PN in case you're interested

Christoph

peter_weatherhead | Wed, 03/12/2014 - 11:33

Hi Christoph,

Was the variable conveyor / surface velocity functionality ever looked at?

Thanks,
Pete

ckloss's picture

ckloss | Fri, 04/04/2014 - 10:06

Hi Pete,

we could develop it upon request. Just contact me via boardmail

Christoph

cTop89 | Thu, 04/17/2014 - 15:40

Usually instead of unfixing the old and fixing in a completly new conveyor, you can "modify" the fix instead. I'm fairly certain that if you put in a fix with the same fix ID, LIGGGHTS will remove the original fix and replace it with the new one (where the only thing different about the new one is that you've changed the conveyor speed). If that doesn't happen automatically you could always unfix it first for the same result.

So the process here is to fix the first conveyor speed, run the sim until the point you want the speed to change, and then fix the same ID again with the new speed. Or in "pseudocode"

...
fix conveyor ... (first speed)...
...
run (steps to reach the time to change speed)
fix conveyor ... (new speed)...
run (the rest of your steps)

There are fix_modify options too but I haven't worked with any of those yet.

I don't know how far you got with restarts, but they can be a little tricky in my experience. If you want a quick run of some the basics and things to watch out for send me a message.

Good luck!

----------------------
"Research is what I'm doing when I don't know what I'm doing."
Wernher Von Braun

peter_weatherhead | Wed, 04/23/2014 - 10:57

Thanks guys,

I have no immediate need for this functionality, but it is something I have required in the past. I would be happy to explore the other approaches, or even attempt to append this functionality to the code myself as opposed to burdening others - but thanks for the offer. Definitely don't want to be doing that if someone else has already done the hard work though.

Cheers,

Pete