AGV can’t find the route, bug or model error?

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Patrick Zweekhorst asked Apr 8, '21 anthony.johnson answered Apr 14, '21

AGV can’t find the route, bug or model error?

Hi,

Attached is a simple example model that shows the question. A little train is created that travel to a control point, stays there for a small delay and then needs to travel to the next control point. The problem is that the AGV network can’t find the route to the next control point.

The picture shows the position of the train when it is waiting at the first control point.
The red circled control point shows the final destination of the train. This means that the train should travel a little further to the right and then travel back and take the other path.

Is this something the AGV network should and could do automatically? Or should the user make extra logic to make this kind of models working?

Note that if you move the first control point further to the right, such that the train has completely passed the intersection when it stops everything works fine.

Also note that this exact same model was running in 2020, although the wagons make a small jump there. In 2021.1 the model behaves the same as in 2021.0.

Thank you for your time.

Patrick

AgvTestTrain.fsm

Software Version:

FlexSim 21.0.4

agv flexsim 21.0.4 trailers train

1617872687283.png (13.9 KiB)

agvtesttrain.fsm (39.7 KiB)

Answer 1 · 2021-04-14T19:04:39Z

anthony.johnson answered Apr 14, '21

Sorry, AGV isn't designed (yet) to properly figure this out. It cannot complete a navigation task where sending either end of the train to the destination would result in that end of the train traveling in on itself. In part this is because it is not necessarily trivial to figure out which side of the train should move to the side before getting onto the adjacent path. Consider the situation below:

Given this situation, which side should the train move to before getting onto paths A, B, or C? It seems that for A, the AGV should move to the right to clear the intersection, whereas to get onto C, it should move to the left. And, for B, I honestly don't know what the rule should be. The train would have to do some heuristic analysis of the intersection's geometry. And while, yes, we could actually do something like that, it's just complexity that hasn't been considered yet in the AGV's routing algorithm. Perhaps we will add something in the future, but for now you'll need to manage it yourself.

1618426902105.png (27.0 KiB)

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