Order picking using transporter in one way aisle

[raashid_mohammed1]

[ FlexSim 16.1.0 ]

Hi

I'm trying to model an order picking process in a very narrow one-way aisle with racks on both sides. See attached model.

I have 300 racks with processors with one bay and 27 levels each so that they can have a unique name. In process flow I am randomly creating orders by bay name and pushing it to a list and then pulling from the list in ascending order with the transporter. The transporter then uses network nodes to go to pick items from the bays. I'm doing this so that the transporter doesn't travel offset when picking items from rack and only follows the network path and its direction

Is there a way I can have only one rack on either side with 30 bays rather than 30 different racks with one bay and have the transporter follow the network logic?

I tried it with one big rack but the transporter goes offset from the network node to pick the items.

Please help.

Regards,

Raashid

[Brandon_Peterson · Accepted solution]

Raashid,

If you don't use travel offsets on the fork lifts then you could use one rack. You would need to update process flow travel task so that it traveled to the network node associated with the bay that the item is in instead of the rack like you have it now. You could reference the nodes by making center port connections from the rack to the network nodes. Connecting the nodes in an order that associates the rank with the bay would make it fairly easy. The center port connections to the network nodes won't be drawn in the view but they will exist. You can check for them in the general tab of the rack's properties GUI.

I hope this helps,

Brandon

[raashid_mohammed1]

@Brandon Peterson

Can you share an example model?

This is what I am trying to achieve

The transporter has to go only one way and feed either side of bay then continue

I tried to create. getting stuck see attached model orderpicking07-01-2016.fsm

[adrian_haws]

@Raashid Mohammed As far as the offset travel goes, you can control that through the process flow through a "Custom Task" activity. See this answer for an example (check the comments).

[Brandon_Peterson]

Raashid,

Here is a modified version of your model. Here are some of the changes that I made:

• I created a Queue called CreationQueue to create the items in before they entered the rack and I modified your process flow a little so that the flowitems would be placed in the correct bay and level of the rack.
  • These changes make sure that the "Bay" and "Level" labels on the flowitem are set before it enters into the rack.
• I created a network node for each bay and made centerport connections to the racks from each node.
  • The centerport connections are used to get an easy reference from the rack.
  • The nodes needed to be connected in the right order for this to work properly. Basically, the node for Bay 1 needs to be first, Bay 2 second, etc.
• I modified the Destination field on the Travel activity so that it would travel to the correct network node.

I hope this helps,

Brandon orderpicking-v2016-1-0-07-21.fsm

[joerg_vogel_HsH]

@Brandon Peterson why shouldn't work the offset travel, too. There exists still the D-connection to link two networks while the taskexecuter is in offset travel mode. If the taskexecuter has loading capacity left and the transport tasksequences are in the right order he travels in the predefined path. If someone want to prevent the taskexecuter to turn to the item to load, the turning can be switched off and you can insert a pickoffsettask, which uses only one coordinate direction to 100 percent. If the standard tasksequence task travel to the destination creates a problem, then you can destroy it or change the tasktype to a tag task.

[joerg_vogel_HsH]

A classic Flexsim approach depends only on several networks which are connected by extended connections, one way paths and the right order of transport tasks. In my attached model I create the right order simply by using a constant dwell time in the rack and a constant load time. All that I mentioned in the comment to Brandon Peterson. I think there isn't a miracle to build such a solution.

rackaisle-load-in-one-direction-v16-1.fsm

After I have tested the Rack option Picking/Placing Y offset which @jing.chen has put to the answers in the thread "How to prevent objects from colliding" I believe that the option makes it a better model. pick-item-in-rack-aisle.fsm

[Brandon_Peterson]

Jorg,

It would. There is always more than one way to do things and each will have its own advantages and disadvantages when compared to another one. In the end it usually comes down to the preference of the person building the model and the objectives that they are trying to accomplish.

I suggested an approach that tried to stay as close to the one that Raashid was already using and limited the amount of coding and complicated topics that would be required.

[Brandon_Peterson]

Jorg,

Thank you for spending the time to supply Raashid with an alternative answer to his question. Now he has multiple options from which to choose the one that best fits his needs. I think that this is a good example of how Flexsim allows users to build models in a way that fits their style and skills. This is a stark contrast to products that require the users to adjust to their approach.

Brandon