topic Re: Dynamic Capacity in Queue / Rack in FlexSim Forum

Dynamic Capacity in Queue / Rack

dominik_k1 — Wed, 03 Jun 2020 14:09:08 GMT

[ FlexSim 18.2.3 ]

Hi.

I want to implement the following: I have 2 Objects. A box and a ball. The box takes 2m^2 of space while the ball takes 1m^2 of space. Both objects go into the queue (e.g. 2 balls and 2 boxes). I have a queue (or rack) and it offers 10m^2 of space.

How can I implement, that the amount of free space changes according to what is in the queue? Technically speaking, a dynamic changing amount of space?

Thanks in advance.

Re: Dynamic Capacity in Queue / Rack

braydn_t — Wed, 03 Jun 2020 14:13:19 GMT

@Dominik K

it looks like you asked a similar question already here: https://answers.flexsim.com/questions/84478/dynamically-changing-space-to-store-goods.html

What else are you looking for?

Re: Dynamic Capacity in Queue / Rack

tanner_p — Wed, 03 Jun 2020 17:17:29 GMT

@Dominik K,

I created a small example model that uses lists and labels to account for the "available space" in a queue. The idea is that items arrive in Queue1 with a label that represents the volume of the item. In the Process Flow, a token is created at the beginning of the model with the available space in Queue2 and that value is pushed to a list. Then, anytime an item arrives in Queue1, the token tries to pull the item's volume value from the list of total queue volume available.

If it is successful, the item is moved to Queue2. If it is unsuccessful after 10 seconds, the item moves to the failedQ. Hope this helps give you an idea of something you can implement in your own modeling.

example queue space.fsm

Re: Dynamic Capacity in Queue / Rack

dominik_k1 — Wed, 10 Jun 2020 10:11:25 GMT

Thank you very much!

I'd have to do the same thing but with 8 different objects. I am honestly susprised about the process-flow-visualization. I did not know this existed. Is there any tutorial you could recommend me in regards to tokens and process flow?

HAve a great day.

Re: Dynamic Capacity in Queue / Rack

tanner_p — Wed, 10 Jun 2020 13:28:10 GMT

Yes, there is a specific tutorial that I recommend. It actually inspired my solution. I'll provide the link to the 19.0 tutorial here, but there should be an equivalent tutorial in your 18.2 (we just don't post the 18.2 and prior User Manuals online).

To do this with more objects, you can add more tokens with references to each of the queues. I updated your model. This may not be perfectly accurate, but if you take some time on the tutorials, I'm sure you'll be able to make this work for your system.

example-queue-space_1.fsm

Re: Dynamic Capacity in Queue / Rack

dominik_k1 — Wed, 10 Jun 2020 13:39:36 GMT

Thanks Tanner!
I will surely check it out.
Is there also a way to do it without the process-flow logic? I feel like not being able to fully understand process-flow within my last +- 100hrs of available work for my thesis...
Regards

Re: Dynamic Capacity in Queue / Rack

tanner_p — Wed, 10 Jun 2020 14:28:49 GMT

I'm sure you could learn Process Flow well in a matter of a few hours. But, as an alternative, you can use an item list and the Pull from List queries that exist in the queue objects themselves.

Here's a version that uses the 3D. I started with the first two queues, and you can practice by adding the others if you'd like.

example-queue-space-1_1.fsm

Re: Dynamic Capacity in Queue / Rack

dominik_k1 — Wed, 17 Jun 2020 10:32:04 GMT

Alright! Thanks Tanner.

I am not sure if this example shows me the possibility to ensure a dynamic capacity change. If the maximum content is 20 and two different item-types are stored in this queue, which both have different sizes, how can I ensure a dynamic change?

So let's say item-A has a capacity-use of 2 and item-B has a capacity-use of 1.

Therefore, in total there could be 10 item-A stored in the queue but no more item-B. On the other hand, we can store 5 item-A and 10 item-b in that queue.
How could I implement a queue whose capacity is dependent on the items stored in the queue?

Greetings

Re: Dynamic Capacity in Queue / Rack

tanner_p — Wed, 17 Jun 2020 19:16:35 GMT

You'll have to forgive me, but I don't see how this question is any different than your first question. You'll have to explain what you mean by "ensure a dynamic change".

In the model, items that have a "capacity-use" of 2 take up 2 of the available 10 spots. Likewise, items that have a "capacity-use" of 1 take up 1 of the available 10 spots.

So if there's only 1 capacity left, an item with "capacity-use" of 2 will not take that spot.

Re: Dynamic Capacity in Queue / Rack

dominik_k1 — Tue, 21 Jul 2020 07:58:12 GMT

Sorry for not answering in so long - I've looked into it again and you did a great job at explaining it, excuse me!

Thanks for your help 🙂

Re: Dynamic Capacity in Queue / Rack

srinivasarao_a — Thu, 09 Dec 2021 09:24:15 GMT

Hi @tanner.p thank you for the model shared here, I am using it to optimize the paint shop load bar capacity, volume as constraint, in this I want to add weight as another constraint.

It should check volume limit as well as weight limit. is it possible?

Re: Dynamic Capacity in Queue / Rack

ryan_c10 — Tue, 14 Dec 2021 19:13:02 GMT

Hi @Srinivasarao A,

Please post this question as a separate post. This helps to keep this Answers website better organized. If needed, you can link to this post for reference in your new post. Please see Best practices for using this Answers site - FlexSim Community for more details. Thanks!