question

K_yun avatar image
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K_yun asked Felix Möhlmann answered

AGV deadlock problem (PathPoint Request & Allocation)

001.png

Here is a deadlock as the pic shows.

I wonder about the request mechanism when a te moves on agv network. What is the request order? In my understanding, OHT2 should not request Path62/pathpoint/1 without having successfully requested Path256/pathpoint/16.

I noticed that, in a small area, more than two pathpoints (CP/CA/ClusterPoint) whose max allocation value is equal to 1 might raise the probability of deadlock.

Thus, is there a way to set the MaxAllocation of the pathpoint like ClusterPoint? I want to make the request for this kind of pathpoint with no limitations. Then I will put only one CP with maxallocation value equal to 1 in a small area so that no request disorder will happen.

FlexSim 23.2.1
deadlocknetworkallocation
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1 Answer

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Felix Möhlmann answered

Allocation timing for transfers is dicated by the distance settings of the accumulation behaviour.

There's an older but mostly still relevant and somewhat longer answer on this from Anthony Johnson who developed the system.

https://answers.flexsim.com/questions/38723/agv-deadlock-because-of-transfer-allocations.html

1726468210542.png

For the issue at hand, you could try to use a control area to limit how many vehicles can enter the section at a time.

Without seeing the model I can otherwise only suggest you let the model run slowly and check the actual allocation timing. If it contradicts the settings, I would ask you to create a new post to report this as a bug while including an example model that demonstrates the issue.


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