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Marc K avatar image
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Marc K asked Joseph Gillespie commented

4-Way Intersection,

I have a 4-Way intersection where forklifts travel down one hallway and personnel cross that traffic to travel down another hallway. I need the staff to stop and wait for the area (4-way) to be safe to cross. I have tried barriers and process flow without success. Is there a simple way to have an intersection with parameters.

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FlexSim 19.0.1
4-way intersection
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Joerg Vogel avatar image Joerg Vogel commented ·

Have you tried the object traffic control?

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Marc K avatar image Marc K Joerg Vogel commented ·

I have. I really thought that a 4-way intersection would be a very common issue; therefore, FlexSim would have made the intersection control have that ability (2 paths crossing). I can have a network node control how many items are in it but I thought if I connected the intersection control to both paths I could do the same with two paths.

I think this would be a very good improvement.

I see the other response to my question. That way is far too much custom code. Crossing paths is a very common issue in manufacturing of any object (people, machine, transporters). The traffic control should perform this.

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Benjamin W2 avatar image Benjamin W2 Marc K commented ·

Hi @Marc K,

Could you share some more details for your model? There might be a simpler solution to your specific model. If you could post a sample model that would be even better.

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1 Answer

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Benjamin W2 answered

Hi @Marc K,

There are several ways to do this. One of the easiest is with process flow.

On a high level:

  • Drag out a Resource activity in process flow.
  • You will need to build in some logic to trigger a token creation when an entity is about to go into the intersection. In the sample model, I have both task executers travelling on a network. Every time they are about to enter the intersection, a token is generated using an Event Triggered Source activity.
  • Whenever a task execute is about to enter an intersection, it will try to acquire the resource using an Acquire activity. If the resource cannot acquire the activity, then use the Max Wait Timer in the Acquire activity to tell the object to stop.
  • When the task executor successfully acquires the intersection, resume the task executor using a Custom Code resume object command.

  • From there, you can use a Wait for Event activity to wait for the task executor to clear the intersection, then use a Release activity to make the intersection available again.

This is one way to accomplish this. However, your model may have specifics that will require modification. Here is another way to do it using PLC emulation:

https://docs.flexsim.com/en/19.1/Tutorials/AdditionalTools/Tutorial3Emulation/3-2AddAreaRestrictionPLCLogic/

I hope this helps!

intersection.fsm


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