AGV custom parking logic

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question

Fred E asked Jul 18, '22 Fred E commented Jul 20, '22

AGV custom parking logic

Hello,
I want to add some parking logic to my model. I want to park the AGVs every time they don't have any task to do.
I can't find the right trigger event to send the AGV to the parking spots.
I'm trying it with the "event trigger source OnStaytimeChange" but then I get weird events where the AGVs park from one parking spot to another. Sometimes it happens that the AGV has no tasks and stops at the last control point, and the event trigger source does not send it to the parking spot.

my model: test160.fsm

Hope you understand my question.
Thank you in advance for your answers.
Best regards

Software Version:

FlexSim 21.2.4

agv event trigger parking point parkign

1658148782391.png (328.2 KiB)

test160.fsm (149.6 KiB)

Answer 1 · 2022-07-18T13:27:24Z

Jason Lightfoot answered Jul 18, '22 Fred E commented Jul 20, '22

You can try OnResourceAvailable and check that NextTS is Null.

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Fred E commented · Jul 18, 2022 at 02:26 PM

I don't think I understand which OnResourceAvailable should I apply. Could you help me with some screenshots please?

or

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1658154321807.png (18.0 KiB)

1658154353723.png (48.5 KiB)

Jason Lightfoot ♦ Fred E commented · Jul 18, 2022 at 03:09 PM

You'll need to test that you're not already parked and that nextTS is NULL.

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1658156920740.png (18.0 KiB)

Fred E commented · Jul 19, 2022 at 08:51 AM

Flexsim crashed after a few seconds of simulation. I think this is caused because resource AGV is acquired by other tasks. So I don't even know how to test this function.

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Felix Möhlmann Fred E commented · Jul 19, 2022 at 09:55 AM

I believe you are running into an infinite loop. The 'OnResourceAvailable' fires again once the AGV arrives at the parking point. Because you also push the parking cp back to list immediately after arrival, the token that is created by that new event can pull it again and travel there in zero time. Which then fires the event again, and so on.

Some modifications you should make:

- Apart from checking if the AGV has another pending task sequence, you should also check if it already is at a parking point. In either case, it does not need to travel to a parking point.

- Only push the parking point back to the list once the AGV actually resumes its tasks. Listening to 'OnAGVTravelStart' can be used for this.

- Finally, at the start of the model the AGVs currently start at parking points without having pulled them from the list. This means if one stayed idle, another AGV returning to the parking area could in theory pull the already occupied position. This probably won't happen with how the model is currently set up, but I would still have them start at some other control points next to the parking points, so they get pulled at the start. Even if just as good practise for future models.

test160_fm.fsm

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test160-fm.fsm (152.1 KiB)

Fred E Felix Möhlmann commented · Jul 20, 2022 at 07:12 AM

This will solve my problem. Thank you for all your tips and comprehensive answers. I learn a lot from your answers.

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