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Bernabe Neri avatar image
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Bernabe Neri asked Bernabe Neri commented

Avoid cranes overlapping

Hi, im trying to simulate a process that involves two cranes moving material between stations.

I have read some questions posted in the forum to solve the issue, so i added collision labels and i have change the handle collision option to add crane logic but still cranes continue overlapping.

1. Material comes from the sources and pass to processors stations

2. After processing the material, cranes moves the material to red queues

3. Next, cranes moves the material to green queue

4. Next, cranes moves the material from green queue to any of two combiner

5. At least the cranes moves material from combiners to final queue

I have problems to attach mi model, so you can write you email and i send you a copy. My email is [email protected]

Thanks

FlexSim 17.2.5
cranesoverlapping
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Cliff King avatar image Cliff King commented ·

I emailed you asking for the model, but nothing...

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Bernabe Neri avatar image Bernabe Neri Cliff King commented ·

Hi Cliff, sorry for the late, i already sent you the files.

Thank you

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1 Answer

Cliff King avatar image
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Cliff King answered Bernabe Neri commented

cranes-line-2-copy-3.fsmWell, I at least got your model working with the collision detection stuff you were trying to implement. The main reason it wasn't working was due to the fact that you misspelled the cranepriority label on one of your cranes. I made a few other changes in the model as I was trying to find the problem, but I believe the main problem was the mispelling. Either way, I've attached the model I got working.

I'm sure the model isn't doing exactly what you want it to yet, because although the cranes do not overlap, only one crane does all the work. The two cranes are always fighting over who gets priority and the crane with the highest value for its "cranepriority" label always wins!

I had some fun playing around with the cranepriority label values for the two cranes while the model was running. Try it yourself by changing which crane has a value of 1 and which crane has a value of 2 while the model is running. Could you get the behavior you want by simply changing the value of the cranepriority labels on the fly for the two cranes using triggers in the model?? Play around with this idea for awhile and let me know what you think?

Another thought would be to change the priority of the requests (i.e. task sequences) being made to the cranes. Should loads be given higher priority than unloads?

You might also want to experiment with what you put in the "Pass To" field of the Dispatcher. Try using "Round Robin" instead of "First Available" and see how it changes things in your model.

Another thought would be to put some controls (e.g. closeoutput/openoutputs) on the queues in the model to restrict the order in which calls are made to the cranes. These are all just ideas. Let me know what thoughts you have and I'll try to help where I can. Controlling overhead cranes working on the same rails is tricky. To have ultimate control you may need to develop some overall control logic that looks at all the work to be done and divvies up the tasks between the two cranes based on some rules that make the most sense. Defining complex logic would be something you'd probably want to do in Process Flow so that you can more easily see the logic in action.


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Arun Kr avatar image Arun Kr commented ·

Another idea will be to use network nodes along with the traffic control. When you use process flow for control logic, you may have to use zone activities for better control.

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Bernabe Neri avatar image Bernabe Neri commented ·

Hi friends, i was working with the model and i apparently could avoid overlapping cranes by moving acceleration and desacceleration parameters also i did all what you said me about cranepriority too.

next i´ll try using triggers to see if the model improve, and i´ll try the other ideas too, to find in which way the model works better.

Thanks for the comments

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