question

Mickael M avatar image
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Mickael M asked Clair A commented

AGV Blocked

I have set up a quick model with two AGV that are supposed to transfer pallet between processors. The model works well at the beginning but The processor 2 is blocked after ~560.

Could you tell me if you have an idea on how I can fix the problem ?

Thank you

test-agv01.fsm

FlexSim 17.2.2
agvagv pathagv process flow
test-agv01.fsm (26.1 KiB)
5 |100000
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1 Answer

Allister Wilson avatar image
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Allister Wilson answered Clair A commented

Hi Mickael.

The queue at the end of your line is setup to only accept 2 items (batch parameters).

Once it has those 2 items, it blocks the rest of the upstream system.

If you allow items to flow out of that queue freely (to a sink for instance), it all seems to work as expected.

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Mickael M avatar image Mickael M commented ·

Thanks to your answer.

It seems that I haev a deadlock issue at 1875.22 :

exception: A circular wait has caused deadlock in the AGV network as follows: TaskExecuter1 is requesting allocation of ControlPoint5 ControlPoint5 is allocated by TaskExecuter2 TaskExecuter2 is requesting allocation of ControlPoint4 ControlPoint4 is allocated by TaskExecuter1

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Clair A avatar image Clair A Mickael M commented ·

Hello Mickael,

Yes the deadlock you noticed is quite obvious: AGV 1 wants to go to the right, and AGV 2 to the left:

So you need to change your network or the logic in your model to avoid this situation.

In the attached model 2017-11-01-test-agv01.fsm, as suggested by @Allister Wilson I've deleted the dispatcher so that one AGV is working on the left, the other one on the rigth, so they never run into each other to cause deadlock situations.

I've also activated this option:

that you can find by right clicking on any path > AGV Network Properties, General tab. It will help you understanding who AGVs allocate/deallocate the network as they travel.

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2017-11-01-test-agv01.fsm (23.6 KiB)
capture.png (46.7 KiB)
capture2.png (1.1 KiB)
Allister Wilson avatar image Allister Wilson Mickael M commented ·

Your AGVs are trying to drive through eachother.

Unless you really need the dispatcher, I'd suggest getting rid of it and connecting your processors directly to the AGV you want to use.

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