Load/Unload after AGV redirect

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Junwoo Kim asked Feb 4, '22 Junwoo Kim commented Feb 6, '22

Load/Unload after AGV redirect

Hello, I have a question about my example model related with AGV.

[1] The following figure shows a screenshot of my model.

Source1 generates flowitems, which will be transferred to Queue1. The AGV (TaskExecuter1) tranasports the flowitems from Queue1 to Queue2.

The AGV moves along the AGV path, which contains 4 control points, ControlPoint1 (front), ControlPoint2 (left), ControlPoint3 (back), and ControlPoint4 (right). In above Figure, the AGV is connected to CotrolPoint1 (front).

The ControlPoints are connected by "NextWorkPoint" connections, however, ControlPoint4 (right) and ControlPoint1 (front) are not connected to each other. In other words, the ControlPoints do not form a complete loop in my model.

[2] I am using "Basic AGV" template of FlexSim 2021 update1 to implement AGV logics for my model. I modify the template slightly as shown in the following Figure, where "TE1 Logic" block is the only part that I added to "Basic AGV" template.

The role of "TE1 Logic" block is to move AGV from ControlPoint4 (right) to ControlPoint1. Note that these 2 ControlPoints are not connected.

[3] The "TE1 Logic" block in above Process Flow contains a Custom Code activity, and its script is shown in the following Figure. We can see AGV.redirect() command is used to move the AGV.

[4] When I start the model, the AGV cycles the path iteratively. So, I think the "TE1 Logic" block works well, at least partly. However, I found that the AGV does not load flowitems from Queue1 at all. In other words, my AGV pass ControlPoint2 (left) without loading, even if one or more flowitems exist in Queue1 object.

Could you please let me know what is missing in my model and how to make my AGV to load flowitems from Queue1?

Thanks in advance.

Software Version:

FlexSim 21.1.5

agv transportation agv redirect

fig1-overallmodel.png (33.9 KiB)

fig2-overallpf.png (57.8 KiB)

fig3-customcode.png (12.7 KiB)

example-afterredirect.fsm (52.5 KiB)

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Answer 1 · 2022-02-04T12:11:34Z

Felix Möhlmann answered Feb 4, '22 Junwoo Kim commented Feb 6, '22

You would have to use "REDIRECT_AS_FINAL" when redirecting the agv. Otherwise it is stuck in the same travel task indefinitely (arrive at cp4 -> get redirected to cp1 -> continue to cp4 -> ...)

This still doesn't seem like a good solution, since the agv will always be redirected, even if it wants to unload something at cp4. Instead you could interject the main loop directly when the agv is at cp4.

I'm also interested to know: Why can't you simply connect cp4 to cp1, if the functionality you seem to target is exactly the same?

example-afterredirect_1.fsm

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1643976557559.png (28.3 KiB)

1643976572059.png (13.5 KiB)

example-afterredirect-1.fsm (65.7 KiB)

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Junwoo Kim commented · Feb 06, 2022 at 09:13 AM

Thanks a lot, Felix. Your advice is helpful to understand more about AGV redirection. I am preparing for modeling of an AGV system, characterized by (i) branching points on the AGV paths and (ii) intermittent transportation tasks (i.e. AGVs do not move continuously). I am going over a couple of approaches including AGV redirection.

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