Get moving direction of AGV

Question

question

Emily K asked Nov 1, '22 Felix Möhlmann commented Nov 14, '22

Get moving direction of AGV

Hi @Felix Möhlmann,

I would like to identify the moving direction of AGVs when they enter the broad phase.

If they are moving in the same direction, turns green and do nothing.

If they are moving in different direction, turns to red, and compare their distancetotravel() to decide they priority

I reference to your post, I guess this could help to achieve what I want to do. As I don't have a strong coding fundamental, I am not sure if I am writing in a correct way, hopefully to get some advices from you.

Thanks!

AgentSystemTrial_221102.fsm

Software Version:

FlexSim 21.2.4

proximity agent system agv travel direction agent system

1667377971221.png (206.5 KiB)

agentsystemtrial-221102.fsm (157.5 KiB)

agentsystemtrial-221102.fsm (156.8 KiB)

· 1

Kavika F ♦ commented · Nov 07, 2022 at 08:21 PM

Hi @Emily K, was Felix Möhlmann's answers helpful? If so, please click the "Accept" button at the bottom of the answer. Or if you still have questions, add a comment and we'll continue the conversation.

If we haven't heard back from you within 3 business days we'll auto-accept an answer, but you can always unaccept and comment back to reopen your question.

0 ·

Answer 1 · 2022-11-02T18:33:03Z

Felix Möhlmann answered Nov 2, '22 Felix Möhlmann commented Nov 14, '22

If both task executers are travelling on the same path when the proximity triggers (which seems to be the case with the way you intend to use this), then you should be able to use the "fromDist" and "toDist" values from the current travelPath node.

If you calculate the difference of those values, the sign (+/-) of the result will correspond to the travel direction.

You should be able to reuse most of the code from the post you linked to. Note though that that code uses "current" to refer to the task executer. Looking at your model, you are using "obj" instead, so you have to adjust the code accordingly. You also don't get a reference to the navigator node ("avgNavNode") at all and instead use "agent.object" a lot. That is just a pointer to the task executer object and not the node you need.

1667413494861.png (44.8 KiB)

1667413982643.png (9.6 KiB)

· 8

Emily K commented · Nov 03, 2022 at 06:31 AM

I have defined the otherAGV.

Object otherAGV = neighbor.object;

Is this the code I could get the node of agent itself and its neighbor?

treenode agvNavNode = obj.find("AGVNetwork>variables/agvs");
treenode agvNavNode = otherAGV.find("AGVNetwork>variables/agvs");

I determine the moving direction by "toDist.distAlong" minus "fromDist.distAlong", however nothing changed in my model..

Could you please give me some advices, thanks.AgentSystemTrial_221103.fsm

0 ·

agentsystemtrial-221103.fsm (156.9 KiB)

Felix Möhlmann Emily K commented · Nov 03, 2022 at 07:30 AM

".find" searches for nodes within the node it is used on. The AGVNetwork is a subnode of the model itself, so

obj.find("AGVNetwork>variables/agvs");

won't find anything, since "obj" is not the model. Even then, this only points to the node that contains the individual agv nodes as subnodes, so you would have to extend the path to point to the correct one.

The faster method, that I use in the other post, is to follow the link node that connects to the agv node in the navigator from the task executer's own attribute tree.

So I use the find method to go to that node and then use the "+" in the path to follow the link it contains, which leads directly to the agv node in the navigator's tree.

obj.find(">variables/navigator/1+");

In the attached model I mostly copied the code from the other model up to determining the current paths of the agvs. I adjusted the task executer references to "current" and "otherAGV" so they fit the code.

Afterwards I check if they are on the same path, if the direction is different (and non-zero) and if the pending travel distance of the current agv is larger. If all of this is true, the current agv is paused by dispatching the utilize task to it, as you propose in your code.

agentsystemtrial-221103_fm.fsm

0 ·

1667460154879.png (10.5 KiB)

1667460589047.png (30.9 KiB)

agentsystemtrial-221103-fm.fsm (155.9 KiB)

Emily K Felix Möhlmann commented · Nov 03, 2022 at 11:16 AM

Thanks for your advices.

Could I ask what is the relationship between them?

In my previous model(agentsystemtrial-221102.fsm), If I define that

Object obj = agent.object;

Is it possible to navigate the node I want if I use the code below?

obj.find(">variables/navigator/1+")

0 ·

1667472732989.png (12.8 KiB)

1667472747451.png (2.8 KiB)

1667472819000.png (8.4 KiB)

Show more comments

Answer 2 · 2022-11-08T06:56:29Z

Joerg Vogel answered Nov 8, '22

I would use a vantage point far outside my layout and compute distances of all AGVs from their current location and a location a few time units before from their kinematic node to get a heading to or from this vantage point. Then I can identify if two AGVs are going to collide or not.

question