Strange cpdistance exception/behavior

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Stefano Crotti asked Apr 7, '22 Stefano Crotti commented Apr 14, '22

Strange cpdistance exception/behavior

Hi,

I do not understand why I'm getting this exception in my model's AGV network.

Resetting and running the model I get this exception:

time: 266.037567 exception: Exception caught in TreeNode::callMemberFunction() c++/dll execution. Throwing... MAIN:/project/exec/usercommandlist/AGV/cpdistance/node c: MAIN:/project/exec/usercommandlist/AGV/cpdistance/node i: MAIN:/project/exec/usercommandlist/AGV/cpdistance/node thisClass: MAIN:/project/exec/usercommandlist/AGV/cpdistance/node
time: 266.037567 exception: Exception caught in evaluation of MAIN:/project/exec/usercommandlist/AGV/cpdistance/node
time: 266.037567 exception: Exception Caught in dispatchtasksequence(treenode tasksequence, treenode dispatcher DEFAULTNULL)

The CP that causes the error is the ControlPoint1746:

in fact, if I run this script I get the same exception:

Object cpFrom = Model.find("ControlPoint1745");
Object cpTo = Model.find("ControlPoint1746");
return cpdistance(cpFrom, cpTo);

The strange thing is that if I show the route accesibility, the ControlPoint1746 can be reached from the ControlPoint1745.

The very strange thing is that if:

I open the model
I press reset
Execute the previous script (before running the simulation)

The script gives me no exception:

and the simulation runs fine, even if I reset and run the model several times.

Could you explain me why my system behaves in this way?

Thank you

Stefano

Software Version:

FlexSim 22.0.1

agv agvnetwork controlpoint cpdistance

cp-errors.png (40.3 KiB)

cp-errors1.png (59.0 KiB)

1649322475528.png (8.0 KiB)

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Jason Lightfoot ♦♦ commented · Apr 08, 2022 at 10:12 AM

We would need the model for someone to take a look.

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Joerg Vogel commented · Apr 08, 2022 at 04:40 AM

I guess, it is the way this module stores a route mapping while it is running. There was a time with FlexSim, when you were able to achieve a different behavior by changing the rank of objects in the model tree. The control point number is an indicator of the model rank. I assume 1746 is behind 1745. If you set 1745 to get an greater rank number than 1746 this can resolve this problem.

But my personal opinion on an AGV Network is, the best supported layout is a design of one direction paths. Only short trunks of one allocatable control point is allowed. You can compare it with a railway network.

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Ryan Clark commented · Apr 13, 2022 at 05:15 PM

Hi @Stefano C2,

We haven't heard back from you. Were you able to solve your problem? If so, please add and accept an answer to let others know the solution. Or please respond to the previous comment so that we can continue to help you.

If we don't hear back in the next 3 business days, we'll assume you were able to solve your problem and we'll close this case in our tracker. You can always comment back at any time to reopen your question, or you can contact your local FlexSim distributor for phone or email help.

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Answer 1 · 2022-04-13T22:27:34Z

Phil BoBo answered Apr 13, '22 Stefano Crotti commented Apr 14, '22

Using another model, we found and fixed a bug in the AGV module with the routing table not being calculated at a certain point when pre-empting, which leads to this type of exception in cpdistance().

This will be fixed in the next bugfix release of FlexSim (22.0.3).

Although you didn't provide a model so that we can verify that the bugfix will fix your model specifically, I suspect that it will.

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Stefano Crotti commented · Apr 14, 2022 at 12:43 PM

You are right, we have this problem and I contacted our local distributor about this issue.

I'll wait for the update then.

Thank you

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