Preferred Path Weight Questions

[ozawa_shinya]

[ FlexSim 22.0.16 ]

Hi,

I'm trying to move the AGV to ControlPoint1 with the A* navigator in the following model, but it doesn't seem to move on the shortest path. I would expect the AGV to behave like when moving to ControlPoint2.

I have a few questions related to this.

1. Why travel threshold is different between ControlPoint1 and ControlPoint2?
2. What is a good way to determine the Default Preferred Path Weight? The weight value of 0.4 gives the expected behavior for this model.

Thanks in advance.

This is the picture of the initial state of this model:

This is the picture after moving to CP1:

This is the picture after moving to CP2:

AStar_sample.fsm

[JordanLJohnson · Accepted solution]

For your first question, the travel threshold depends on the position of the object relative to the grid nodes and to other barriers:

The algorithm used to generate the thresholds is sensitive to these relative positions.

For your second question, the best way to determine if the weight is correct is to try different weight values until your model behaves correctly. The weight value represents excess weight given to the path. More weight means the path is more likely to be used by travelers. There isn't a more formal method because each customer has unique requirements.

[ozawa_shinya]

Thanks for the info. I understood most of it.

However, in this model, setting the Default Preferred Path Weight to 0.4 from 10 yields the path becomes used by travelers.

Can a Default Preferred Path Weight that is too high make the pass less likely to be used by travelers?

[JordanLJohnson]

It looks to me like the weight of 10 is somehow an issue. It's no that it's repelling travelers. It's just changing the search algorithm for some reason. If the weight is 10, it doesn't seem to matter where I put the preferred paths. They can be very far away from the travel, and still the AGV goes to the incorrect location. If I changed the weight to 0.4 (I'm wondering if it's less than 1?) or if I deleted the Preferred Paths, the routing looks normal.

I've added this to the dev list. If it is by design, I'll get enough information to explain it. If it's a bug, we'll fix it.

[ozawa_shinya]

Thank you for adding this issue to dev list. If it's a bug, I hope it will be fixed as soon as possible. In the meantime, I try path weights less than 1.

[JordanLJohnson]

We reviewed this question as a dev team and determined that the weight for a Preferred Path should be be in the range [0, 1]. This resulted in a couple additions to the dev list:

• The documentation needs to be more clear about this range
• The UI should prohibit values outside this range.

So your plan to use values in that range is the correct choice.

[ozawa_shinya]

Thank you for your information.

[Jeanette_Fullmer]

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