Double Shuttle Car

[douglaslima]

[ FlexSim 24.0.0 ]

I'm trying to simulate a double shuttle car in a palletizing area. This shuttle works for 7 palletizing lines. The shuttle must pick up 2 pallets at a time from the same line. Pallets from lines 1, 2 and 3 must be delivered to conveyor A and pallets from lines 4, 5, 6 and 7 must be delivered to conveyor B. How can I simulate it?

[moehlmann_fe · Accepted solution]

The attached model demonstrates a possible approach.

The Exit Transfers push the task sequence to transport the items to a list. In the Process Flow, each time something is pushed to that list, a token is created that pulls the entry from the list again. The tokens are batched into pairs according to the Exit Transfer that the item is at. When two tasks are available they are dispatched to the operator.

conveyor-batched-transfer-fm.fsm

[douglaslima]

But this is part of the solution. I would like there to be a shuttle car with 2 slots instead of an operator. And this shuttle would take the products from conveyors 1, 2 and 3 to conveyor A and the products from conveyors 4, 5, 6 and 7 to conveyor B.

[moehlmann_fe]

Replacing the operator with a different type of task executer and adding additional conveyors are basic tasks you should have any difficulties with.

Just check the settings on the existing objects and copy those and in the case of the operator, add a different task executer and replace the reference in the "Dispatch TS" activity in Process Flow.

[douglaslima]

Is there any task executer in the library that can take 2 objects at the same time? I mean.. go to the position, take the first object and then switch the position and take the second object and do the same to delivery the object. Other way I assume I will need to create something to simulate that.

[moehlmann_fe]

Every task executer can load any number of items if you set the capacity accordingly.

You can control how the items are stacked on the task executer by setting their location in the On Load trigger. https://docs.flexsim.com/en/24.0/Reference/CodingInFlexSim/FlexScriptAPIReference/Tree/Object.html#M...

https://answers.flexsim.com/articles/148707/changing-task-executer-stacking-rules.html

For more fine control over the loading and unloading sequence, do not use the "Use Transport" option on the Exit Transfers. Instead push the items to an item list in the "Send to Port" option. Then use Process Flow to pull two items from the list and create a custom task sequence with the respective activities.

You can look at the Process Flow Task Logic Tutorial to get started with learning.

If you need more information, I would recommend to post a new question with that specific topic.

[douglaslima]

Thank you so much, my friend! My simulation is almost perfect. I only can't figure out how to fix a small bug when the shuttle tries to position itself on Line 10. Could you help me?

Shuttle.fsm

[moehlmann_fe]

The network nodes at lines 6 and 10 are only connected two one other node each. The shuttle will have to move along the blue arrow in the picture below to move from one to the other. I guess this might be your issue?

Also, the centerport-connections between the task executer and network nodes are not needed.

[douglaslima]

I have tried to do what you said, but it's not working. Do you have any other ideas?

[moehlmann_fe]

What changes have you made to the model and what is still not working as expected?

[douglaslima]

I've assigned individual network nodes to the lines, similar to the image below:

However, the simulation is crashing.

Additionally, I have another question: How should I establish the connections for the shuttle car?

[moehlmann_fe]

The screenshot didn't upload successfully, so I can't comment on the network node connections you made.

The task executer needs a centerport-connection to each exit transfer it should pick up items from (as long as the default setting of the "Use Transport" option on the transfers is used).

Here is a working example.

shuttle_1.fsm