AGV does not take the shortest route

[patrick_zweekhorst]

[ FlexSim 22.2.2 ]

Hi @anthony.johnson ,

We are working on an AGV model and we came up with some questions/problems.
Attached to this post you find a model that is just the start point. The AGV picks up 1 rack, drives it to a replenishment station and drives back into the warehouse. The first thing we notice is that the AGV does not take the shortest route. We would expect the AGV to take the green route, but it takes the red routes:

Could you think of any reason why this happens?

We thought to refresh the path links, but doing that will throw an error when the AGV tries to load the rack. This seems to be a small bug?

Also the route back to another control point does look a bit weird, but I guess that can be the same problem/bug as our first question. We are using the AGV.RoutingConstraint properties, maybe that has something to do with the issues we have.

Thank you for the help.

Patrick

AgvGridModel_5.fsm

[patrick_zweekhorst]

@anthony.johnson ,

Would you have some time to look at this and to see if we are doing something wrong in the model or if there is a bug?

[anthony_johnsonT83CM · Accepted solution]

This is a bug in the user customization delegate. You had added a user customization delegate, but had not toggled the getPathTravelWeight node as flexscript, and it doesn't check if the nodes are toggled for code, so it was returning 0 for the travel weight of everything, which was messing the A* algorithm up. I'll make a change to check the code toggle before evaluating. As a workaround, you can toggle the getPathTravelWeight node as flexscript and return -1, which means use the default travel weight.

[andrew_o2]

Hi @Patrick Zweekhorst, was anthony.johnson's answer helpful? If so, please click the "Accept" button at the bottom of their answer. Or if you still have questions, add a comment and we'll continue the conversation.

If we haven't heard back from you within 3 business days we'll auto-accept an answer, but you can always unaccept and comment back to reopen your question.

[patrick_zweekhorst]

Hi @Andrew O, The answer was definitely helpful. Just 1 thing. I did not get any email notifications that an answer was posted, or that your comment was posted. Just by accident i noticed that you posted something. Would you know why I am not getting any notifications?

[Matthew_Gillespie]

@Patrick Zweekhorst This bug has been fixed for 22.0.10 which comes out next week.

[LariWalker]

Hi @anthony.johnson. I'm having a similar issue where I have a grid patterned AGV path and one AGV on it (for now). Each AGV cycle there is a randomly selected "hole" it is assigned to and travels to. Since it's a grid, the shortest path should be basically X then Y, but if you sit and watch it for a few cycles you'll see it doing paths like this:

When it would have been better to do something like this:

All my paths are straight, two way paths with no specific weights attached to them.

Thanks!

AGVBasedModel_share.fsm

[anthony_johnsonT83CM]

https://docs.flexsim.com/en/23.0/Reference/Tools/AGVNetworkTool/AGVNetwork/AGVNetwork.html#general

Check the box “create transfers at crossings” then right click a path and refresh all path links.

[LariWalker]

Hi @anthony.johnson, thanks for the response!

I'll do a better job at reading all the relevant documentation - promise! In this case, somehow doing as you suggested didn't fix the issue. Did it work on your end? Maybe I'm doing something wrong.

[jason_lightfootVL7B4]

At what time are you seeing a problem ? I could not detect the issue.

agvbasedmodel-share_jl.fsm

[LariWalker]

The route that starts at around 40s looks like this to me

[jason_lightfootVL7B4]

Try adding a custom path cost to try and reduce the number of paths taken.

eg.: