topic Re: How to solve deadlock problem? in FlexSim Forum

How to solve deadlock problem?

Penny1 — Sun, 07 Apr 2024 20:18:00 GMT

[ FlexSim 23.2.1 ]

I have set up a model with several AGVs.

During traveling, two of AGVs will always deadlock on the one road.

In this case, I want to preempt both AGVs to stop at their current control point. Then restore one of the AGVs first (maybe let the AGV move to the next two control points.), and then restore the second AGV after the first restored AGV leaves the area.

So I decided to use Process Flow to accomplish this.

But I don't know how to write my idea into code...

Can anyone help me complete this?

deadlock.fsm

Re: How to solve deadlock problem?

kavika_faleumu — Tue, 09 Apr 2024 15:49:10 GMT

Hey @mni_pei, there's a section in the documentation that talks about preventing deadlocks in an AGV network. Your problem specifically occurs because of all the two-way paths. When an AGV is trying to route somewhere, it will choose the shortest path, which may be backwards. If you have another AGV right behind it (which is guaranteed in your model because they all start at the source of boxes), then you will get a deadlock.

I recommend restructuring your model to only use 1-way paths OR to increase the max-allocations at the Control Points so you can have multiple AGVs at one station and they can pass through each other.

Re: How to solve deadlock problem?

Jeanette_Fullmer — Mon, 15 Apr 2024 15:21:36 GMT

Hi @mni_pei, was Kavika F'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.

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