Collision when using A* Navigator

[maria_a10]

[ FlexSim 21.1.2 ]

Hi, for a storage model I'm programming I used the A * navigator to limit the transporters from getting into the racks, but there comes a point in the run that the transporters collide and cause the model to collapse. It would be helpful if you can tell me how to solve this problem. I am attaching the document in case you want to review it.Modelo Final T123.fsm

[eric_m3]

Hi @Maria A10, at what model time are you having this issue? It's running for me, but I did notice there are times when the transporters pause for a while (using step will get through those parts).

[maria_a10]

The time where this happens varies, but for example every time I give FastForward I see that in the end the system crashed and one of the indicators that it is okay would be that it did not crash.

So there is no specific time because each run is different, but it always happens. 😞

[maria_a10]

[eric_m3 · Accepted solution]

Hi @Maria A10, thanks for the further explanation. Here's a section from the manual that might help explain what's going on. A* assigns the transporters to a node that's closest to the center of the transporter. A* treats this node as occupied so no other transporter can occupy it. The problem is that the nodes around the occupied node are still available for other transporters to use. The image below shows the occupied node for this transporter. Since the transporter is much bigger than this node, they appear to collide with each other.

The only real options to help with this are to increase the spacing between the nodes (which sacrifices travel accuracy) or decrease the size of the transporter. Spacing out your model a little more might help as well with the increased node spacing. You might be able to use preferred paths to help guide the transporters to paths where they won't be in collision with each other.

[Jeanette_Fullmer]

Hi @Maria A10, was Eric M's answer helpful? If so, please click the red "Accept" button at the bottom of their answer. Or if you still have questions, add a comment and we'll continue the conversation.

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