Non-blocking conveyor picking using robots, how should cancelled picks be handled?

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Allister Wilson asked Nov 7, '16 Clair A commented Nov 22, '16

Non-blocking conveyor picking using robots, how should cancelled picks be handled?

In the attached model, there's a robot picking items from a conveyor to fill a batching queue.

The transfer is setup to not stop items, and it seems unpicked items aren't (always?) releasing their reservation in the queue when they pass the end of the transfer, resulting in items no longer being sent to the queue and the batch never being completed.

Is there something else I should be doing to ensure items release their "spot" when they leave the transfer area?

I'd be interested in possible workarounds if this turned out to be a bug.

conveyor-robot-ignore-late-picks.fsm

Software Version:

FlexSim 16.2.1

conveyor robot picking exit transfer

conveyor-robot-ignore-late-picks.png (85.5 KiB)

conveyor-robot-ignore-late-picks.fsm (27.0 KiB)

Answer 1 · 2016-11-09T14:10:34Z

Joerg Vogel answered Nov 9, '16 Clair A commented Nov 22, '16

If the item reaches the end of the ExitTransfer, a Photoeye trigger create an aborting and destroying tasksequence for the current transport tasksequence. The Trigger looks for any existing tasksequence in the tasksequencequeue, too, wether it is needed or not, which transport the blocking item.

fetch-items-synchronous-conveyor.fsm

fetch-possible-item-by-roboter-conveyor.gif (420.3 KiB)

fetch-items-synchronous-conveyor.fsm (27.6 KiB)

· 1

Clair A commented · Nov 22, 2016 at 11:28 AM

Thank you very much for your answer Jörg, it's working perfectly with this arrival schedule.

However if you increase the arrival rate like in the attached model synchronous-conveyor-arrival-rate-incr.fsm, you get boxes hierarchically inside the exit transfer, and visually stopped out of the conveyor. When adding a breakpoint in your code, this occurs when transportoutcomplete is called.

fetch-items-

0 ·

fetch-items-synchronous-conveyor-arrival-rate-incr.fsm (27.6 KiB)

box-out-of-conveyor.png (49.4 KiB)

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