Why does the arrival time of the AGV differ from what I expected?

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mni_pei asked Jun 23, '24 Felix Möhlmann answered Jun 24, '24

Why does the arrival time of the AGV differ from what I expected?

I created a from-to table and hope that AGVs can load and unload objects at specific times according to the from-to table.

For example, I hope that at the 0th second, the AGV can run from Node_1 to Node_2, and at the 5th second, perform the unload action on Node_2.

The current model seems to be running smoothly.

However, when I recorded the real time when the AGV arrived at a specific point, I found that it was different from what I expected.

( I wrote a custom code to record the model time before the AGV travel.)

I want to know if I am using the wrong method?And how to solve this time problem?

I attached file here.

Thanks in advanced.

Example2_multiload__autosave.fsm

Software Version:

FlexSim 23.0.15

processs flow globaltable model time

1719137094250.png (197.4 KiB)

1719137195893.png (69.8 KiB)

example2-multiload-autosave.fsm (89.1 KiB)

Answer 1 · 2024-06-24T06:36:48Z

Felix Möhlmann answered Jun 24, '24

The tasks in the "fromto" table do not happen sequentially by row, but you note the times chronologically. This means the time for row 12 (0s) ends up as the second row.

You can fix this by storing the from-to row a token belongs to on a label and then write to that row in the "fromto" table directly. Doing this you end up with mostly correct times. TE1 is delayed at the start because not all types of items are immediately available. I did not check what causes the 0.04s delay a bit later on. But you can just set a stop time at the relevant time and check why the token doesn't continue immediately.

example2-multiload-fm.fsm

1719210962417.png (83.4 KiB)

example2-multiload-fm.fsm (89.3 KiB)

Answer 2 · 2024-06-23T11:03:26Z

Joerg Vogel answered Jun 23, '24

@mni_pei, you are a dispatcher for arrival times and departure times. You will estimate time of arrival by duration of travel to destination of departure. Your vehicles must be at the right location at the right time. And to achieve this, your vehicles arrive a bit earlier and will wait until an action of loading should happen. You have to explore durations of travel from one location to any other locations. You will increase expected travel times to compensate delays of blocking and breakdowns.

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