How can the AGV process flow assign multiple items to same pickup point?

osman_eralp1 — Wed, 09 Nov 2016 21:01:25 GMT

[ FlexSim 16.2.1 ]

When I use pickup points, only one work item is available at each point. Is there a setting that enables multiple items to be picked up at a pickup point?

The capacity of the AGV is >1. When I don't use pickup points, the AGV picks up multiple items at once.

TIA.

Re: How can the AGV process flow assign multiple items to same pickup point?

sam_stubbsYXX86 — Fri, 11 Nov 2016 14:41:59 GMT

I believe this article on the forum can help you figure out how to get an AGV to load multiple items:

https://answers.flexsim.com/questions/23793/how-to-load-and-unload-a-trailer-agv-1.html

There is also this answer too that you may find helpful, it talks about using a coordinated task sequence to load multiple items:

https://answers.flexsim.com/questions/28047/how-to-pick-up-multiple-items-in-coordinated-task.html

Re: How can the AGV process flow assign multiple items to same pickup point?

anthony_johnsonT83CM — Fri, 11 Nov 2016 17:12:56 GMT

This can be done with a few changes to the AGV process flow.

The default design was to only allow one item at each pickup point. The logic is in the Item Pickup section of the process flow. There is a pull from list activity called Get an Available Pickup Point that pulls from a list of available pickup points. The critical piece is that, when it pulls the pickup point from the list, it actually removes it from the list. This means that each time an item arrives, it will select an available pickup point, and remove that pickup point from availability. Once the item has been loaded, there is a Make Pick Point Available activity that then pushes the pickup point back onto the list, making that pickup point available again. In order to make it so multiple items can go to the same pickup point, you'll need to change the logic so that it doesn't remove it from the list, i.e. the pickup point will continue to be available for other items to select.

Below is a picture of the spots that you'll need to change.

1. In Get an Available Pickup Point's properties, first change the Query to include a WHERE clause that constrains the content. Something like: WHERE content < 2 ORDER BY distance. This means that if a pickup point already has 2 items, I don't want to add another item on.

2. Still in Get an Available Pickup Point's properties, check the box Leave Entries On List. This will let the pickup points remain on the list for other items to select.

3. This step isn't essential, but it lets you see the different items better when they're put into the pickup point. In the Set Item Location activity's properties, change Z Location to:

zsize(getlabel(token, "item")) * (content(up(getlabel(token, "item"))) - 1)

4. Remove the Make Pick Point Available activity from the process flow. Since you're now leaving pickup points on the list, you don't need to push it back on after the item's picked up.

5. Finally, introducing a WHERE into the pull query introduces a new complication, namely for when there are no valid pickup points available (all points are filled to their 2 capacity limit). There is nothing to tell the list to re-evaluate its outstanding pull requests when an item is picked up, making a new slot available. To get around that, you'll need to add a back order re-evaluation event to the global PickupPoints list. You do this through the list's properties (Toolbox > PickupPoints properties > Back Orders tab). It should be a value based event that listens to the value's "OnExit" (the "value" is the value of a given entry, which in this case is a given pickup point control point).

Re: How can the AGV process flow assign multiple items to same pickup point?

osman_eralp1 — Mon, 14 Nov 2016 16:07:03 GMT

Thanks very much for the detailed answer. This is exactly the info I was looking for!

topic How can the AGV process flow assign multiple items to same pickup point? in FlexSim Forum

How can the AGV process flow assign multiple items to same pickup point?

Re: How can the AGV process flow assign multiple items to same pickup point?

Re: How can the AGV process flow assign multiple items to same pickup point?

Re: How can the AGV process flow assign multiple items to same pickup point?