question

heather.ulrich avatar image
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heather.ulrich asked tannerp commented

Multiple AGVs Not Processing Properly

agv-issue.fsm

Is I'm using a dispatcher and 4 AGVs to move material to each of the stations. I get the 1st and 3rd AGVs to pick up material and move around the network, but the 2nd and 4th AGV stay at the starting point an don't move even though there is a part to pick-up. Why is this?? They are all connected the same way so I would figure they would act the same way. What do I need to do/change to make these AGVs work properly?

FlexSim 18.0.10
agvdispatcher
agv-issue.fsm (57.0 KiB)
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1 Answer

zacharyh avatar image
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zacharyh answered tannerp commented

First thing I noticed was that you had a connection problem which was connected backwards between the TaskExecuter2 and the Dispatcher. The AGV3 connection to the dispatcher was made before the AGV2 so that is the reason why AGV3 was sent before AGV2. The connection between TaskExecuter1 and Parking Lot needed to be created as a "Traveler AGV" (red line), not as a "Location connection" (blue line.)

The Dispatcher is also giving commands to the first available AGV according to how it is connected to the dispatcher which happens to be the first AGV, unless it is already busy. It is then deadlocked in its path because AGV3 and AGV4 are in its way. In your simulation you can change the Command passing to "Pass to the object closest to the destination if available." This seems to work for your model let me know if it's not what you're looking for.

multiple-agvs-processing.fsm


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heather.ulrich avatar image heather.ulrich commented ·

@zachary.h So the model runs and then stops about an hour into the day. The AGV gets stuck at Processor4. It looks like it is waiting for the operator to load, but when the operator is done working he doesn't go and load.. Why is this?

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tannerp avatar image tannerp heather.ulrich commented ·

Usually this happens because there aren't any available control points. If you review the AGV Tutorial then you'll notice that deadlock can happen when there aren't sufficient control points in a system. Have you updated your model to include dispatcher logic? If so, you can post it here and we can take a closer look at it.

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tannerp avatar image tannerp heather.ulrich commented ·

You also might consider using parking spots that are outside the main loop of the AGV system so that the AGVs can be out of the way when not in use. I've attached an example of that.

Also, your TaskExecuter2 was not connected to the dispatcher, which was also causing problems.

agv-issue-update.fsm

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