I thought I recall seeing the three solved AGV Tutorial models in the product installation area. I'm having trouble getting my AGV Tutorial #3 model to work, have built it twice and still not working right. The source winds up "blocked" after just 2 flowitems, and the AGVs do not park (they circle around empty).
Was hoping to compare mine with a correctly running solved model to see where I went wrong. Thank you!
Does the problem exist if you use version 17.1.6? We have fixed many AGV bugs since 17.1.2
Jordan, thanks for the suggestion on version.
I downloaded and installed 2017.1.6 just now, however it's experiencing the same issues as before, with the model I created with the third AGV tutorial. The first two tutorial models work fine, it's the third one I'm having trouble with. I've attached my tutorial model to see if something jumps out at you that I'm not seeing.
Here's more specifically the behavior I'm seeing (in both 2017.1.2 & 2017.1.6). Note that my model stops short of the point in the tutorial where speeds are changing on the curves, i.e., the entire tutorial is not in my model because I was having trouble up to that point so I stopped half way thru the tutorial until I could figure out what I did wrong. I suspect it's something simple, I'm just not seeing it.
AGV Tutorial "Lesson 3":
- The two transporters do pick up the first 2 flowitems correctly from the Source1 PickupPoints. Note it's set to exponential(0, 100, 0) so it won't create the first flowitems right away when you run it.
- Note that the model is running with AGV transporters, and you will also see OperatorJane & OperatorJohn, which are not connected. The behavior is the same though, when I swap the AGVs for the two humans.
- They correctly deposit each flowitem at the Sink1's Dropoff Points.
- The Source1 goes into a blocked state, no longer able to send out flowitems other than the initial two flowitems. I can't figure out how the source gets blocked after only 2 flowitems.
- As a result, the transporters continue traveling around the loop continuously. They have nothing to pick-up from the Source1 area (because it's blocked).
- The transporters also do not park themselves at the specified ParkPoints, which is the second thing I can't figure out, since if they have no tasks, they should park themselves. I think that's how it's supposed to work, per the tutorial text.
- In the AGVWork list (in both the Entries and Back Orders list views) the only item visible is "id:3 instance: TaskExecuter1" in the "puller" field of "AGVWork Back Orders" view. It doesn't go away or change, and there is nothing else in the "AGVWork Entries" list view. I would suspect normally that those two AGVWork list views would have items coming and going as they do their work, so maybe that's a hint as to the problem.
And Matt thanks for the info on the Tutorial models. It might be that I was confusing thes
e with the solved models from our training class a while ago.
I'm pretty sure the solved tutorial models have never been included in the installation.
This certainly seems like a bug. For now, to get it to work, you will need to switch two activities in the AGV template (until we fix this issue, anyways). If you look in the Item Pickup container of the template (inside the Work Generation container), you will see two Wait for Event activities. Make it so that Wait for Pickup Point Deallocation is before/above Wait for Item to be Loaded. If you ctrl-drag, you should be able to move the bottom activity up without unsnapping it from the block.
EDIT
As a better solution, I would change the Deallocation Type on the pickup point control points. I think they need to be Deallocate When Past Current. Then, the original AGV template should work.
Hi Jordan,
Thank you for looking into it and determining that there is a bug. Thanks also for your two workarounds. I tried both.
The first one (swapping the process flow order so that "Wait for Pickup Point Deallocation" is before/above "Wait for Item to be Loaded") does seem to work for the most part. There were times however when the TE would park itself while there was still a flowitem waiting to be picked up though, or, times where the second TE was idle but would not go get a waiting flowitem while the first one was still in the middle of transporting the other flowitem to the sink.
The second workaround you suggested works pretty well. When the model first starts running, the first TE gets the first flowitem. When the second flowitem shows up, the second TE starts towards it but goes to Parking instead. Which leaves the first TE to also go get the second flow item, after it drops the first one off. After that though, the model seemed to sync-up and run just fine and both TEs seemed to fetch flowitems as they are showing up (or go to park when there's no work to be done).
On a whim, I tried a third option, which was to combine both your first and second ideas, which interestingly did solve that initial blip in your second workaround (i.e., now the second TE does get the second flowitem instead of going to park) however after that they just kept circling and the Source1 went into a permanently blocked state.
So, your option 2 workaround is the best one, barring a bug fix in FlexSim as you had noted. I'll finish up the tutorial then see if I can weave this logic into my existing model, which is very similar.
Thanks again!
Mike
I have successfully created the Tutorial 3 model where 2 operators walk around a rectangular loop looking for work, picking up on one side of the loop and dropping off on the other side of the loop. Then, parking if there's no work to do.
My next challenge is to do the same thing but with an open-ended U-shaped back-and-forth loop. Like a horseshoe, and without the need for parking. The operators simply walk back and forth, between the ends of the horseshoe path (they turn around at each end), looking for (and doing work) at the 12 stations along the way.
My thinking is that two operators (TE's) go back and forth along the horseshoe AGV track looking for work at the 12 stations spaced along the way. When they come to each end the U-shape (the top end of each stem in the U), they simply turn around and continue walking back the same way they came, looking for work. Each station along the way simply needs something moved from one side of the track to the other.
This is actually no different than 2 TE's going back and forth on a straight line, turning around at the ends and going back on the same track they came. Except bent into a U.
I've attached my model but of course it's not working (because I'm still learning how they work), but the goal is to have the ability for the operators to pass each other in either direction, as well as for one to go around another who might be standing doing work. Then turn around and walk back the other way when they hit the U ends. Just like real humans might do walking back and forth around a U-shaped counter looking for work (like 2 bartenders working a U-shaped bar).
Another thought, I wonder if I'd be better off with a dual-path U-loop, with a semicircle at the U-ends as a turnaround. I.e, two actual parallel tracks in a U-shape. Kind of like downtown circulator buses, going back and forth in a U shape but following two actual paths - one on either side of the streets they are traversing.
With the exception in the case of the operators, is that they will need to move laterally (i.e., across the street) to carry the flowitem(s) from each source to each corresponding sink on the other side of the track(s).
Thanks for any thoughts.
Mike
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