A Lifttruck between two Nodes

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Re: A Lifttruck between two Nodes

Post by vahid.bgh »

Ha Harry
I did just as you said and I will attach a new file that there is no need to look the previous one.
There is another problem with this code and it is that in VNA models between two aisle there are 2 warehouses; the problem is that when a lift truck goes for wh3 and the other one is going for wh4 they cross over each other and don't block.
t switch nodes.mod
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Re: A Lifttruck between two Nodes

Post by HarryBunnik »

Ha vahid.bgh,

Yes, when you're using a path that is 2 way, it is expected that the AT's can pass. So, in other words, the capacity is only valid in one direction. To have a network that is in the aisles bi-directional, but still is not allowing trucks to drive past (or through) each other, will require some coding.

Additional programming is needed and even then, it will be quite complicated because at the moment you only have 2 trucks, so that is "easy" to have an overview. But when the warehouse gets bigger, there will also be more trucks driving.
  • You'll need to keep track of how many trucks there are in an aisle.
  • Which side they entered
  • Where they need to drop/pick something off/up. If they would cross, one of them has to wait.
  • When a truck is coming from behind, you'll also need to know where the truck that is already in the aisle will go to. Does it back up or drive on.
And so, I can think of several other complications.

There are many things that you'll have to consider and even then I think you'll find many situations in which you'll have deadlocks. So, I would aim for a solution where, once a truck is entering an Aisle, the complete aisle is blocked.

Then it might be an option to use the RFID gates to let the nodes have an Entry trigger and an Exit trigger (in the latest version of ED you can arrange that on the nodes themselves).

There you can "manipulate" the nodes on the other side of the aisle by incrementing the capacity and thereby "blocking" the aisle.

Additionally, I would use a table to keep track of your administration. That way you have a central point in which you have an overview.

I hope this helps you a further!


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