Objects skipping Tasks in Process Flow

[mia_mancheski]

Good afternoon everyone!

I need your help!!! I've been trying to simulate an inspection process flow for hours now but I've been running into a few problems. The first was that once I was able to get everything set up, the operators would act funny. Some operators would hold multiple boxes (even though their capacity is at 1), while others would be walking around with nothing in their hands going back and forth while their state said that they were walking with a load. Others would also take a box that was already processed and bring it back to the first queue instead of moving it to the pass or fail queues. Some of the operators would just stand around. At the same time, some of the processors would be processing even though I set it to process only if the specified operator is present. I tried fixing it but then the source objects suddenly appeared into the queue without needing to be moved from the truck by operators. I then deleted that option to go back to the original version but now it is stuck. I tried using the Tutorial 2.1 as a stepping block to this set up but I may have messed with it too much. 

It is small set up simulation but I'm still learning how to use FlexSim so if anyone knows the issue and how to solve it, PLEASE lmk! I have attached my simulation file below!

[moehlmann_fe · Accepted solution]

Most of the weird behaviour stems from having overlapping logic. If both the Process Flow and the port-connections in the 3d model create a task to transport an item, then there will be two operators assigned to the same item. This results in the item teleporting to the second operator when they load it, for example.

Always be aware what part of the model controls what. Your v2 Process Flow is working well on its own with the exception of missing a proper unload location for the item after the inspection is finished. In the attached model I fully control the transport from the truck to Queue1 and then to an inspection station through the Process Flow. The rest uses the logic of the 3d objects. To keep using the same operator I write a reference to it to a label on the box. The Process Flow only reacts to certain milestones by releasing the station and operator resource.

Two other things that I noticed that lead to weird behaviour:

- "Logistics Team 1" was set to not travel offsets. The travel portions of load and unload tasks are offset travel though, so this setting results in items being moved by that operator just teleporting around.

- Some event nodes somehow ended up as subnodes of the first two operators (I really don't know how you managed that). Them having subnodes means they are treated as being "loaded" and thus use the respective state and animation, even if the subnode is not an object.

[mia_mancheski]

Thank you! It is working now.

Was the issue just that I didn't put a sink task at the end of the process flow? I also saw that you took out some of the process flow logic. Does this mean I only need to code either the objects or the process flow? If so, then when do I know when to put logic in the object model versus the process flow model? This seems to have been the issue with the transport from the truck to Queue 1. Does this mean that I just needed to keep the process flow model without making changes to the truck's output behavior in the object flow model?

Also, I have no clue how some event nodes ended up as subnodes, esp. considering I have no idea what that is. How could that happen so I can avoid doing it again? How did you manage to fix it?

Thanks a billion!!

[moehlmann_fe · Accepted solution]

In your v2 Process Flow the items were being unloaded to the taskExecuter (the operator) at the end, not one of the queues.

Instead of implementing logic that decides where to unload in the Process Flow, I opted to use the port-connection logic in the model for this. Knowing when to use Process Flow or the 3d-logic comes mostly with experience. Process Flow is generally used when the logic is too complex to be easily implemented with the options of the 3d objects. For example doing tasks in a specific order, possibly waiting for items to become available instead of starting some other task.

To avoid weird errors like the wrong subnodes, make sure that you always use the correct label names and that those labels hold valid and correct values. I assume those event nodes were somehow "loaded" und "unloaded" into the operators due to a wrong label reference.