Travel Network Question

I'd like to build a travel network that will go through aisles between racks where a TE will pick up objects. Aisles can be entered from either end, but once a TE enters an aisle, the aisle becomes one way in the direction that the TE is traveling. Once the aisle is empty again it switches back to where a TE can enter from either end. How would I accomplish this? Does anyone have an example?

Thanks,
Courtney

Courtney,

You can add a traffic controller for each lane. Use the 'A' key to connect the two nodes to the traffic controller. Follow the steps below:

1. Open the traffic controller and select the Untimed Traffic Modes from the Traffic Control Mode drop down list.
2. Set the number of Modes to 2.
3. Set the Max_Nr cells to the maximum number of TEs that you want to allow in the aisle at a time.
4. On row 1 enter the name of the first node in the From column and the name of the second node in the To column.
5. On row 2 enter the name of the second node in the From column and the name of the first node in the To column.
6. Click "OK".

No you should see that the aisle will only allow for one way travel when a TE is in the aisle. If this isn't working for you then you will probably need to post the model or a sample model that illustrates the problem you are having.

Good Luck,
Brandon

Brandon,

I've done what you said and it doesn't seem to be working. I've attached a small sample model. When a TE enters the aisle between the 2 racks I'd like for it to exit at the opposite end. Have I missed something?

Thanks,

Courtney

Courtney,

First, when you put in the names of the network nodes you didn't put the names in the cells but rather just a number. Those fields require the name of the node so it wouldn't have worked. Regardless the problem you were looking at required a different solution anyway.

Here is a sample model that does what I think you want it to do. I changed the traffic control mode, added four new nodes, and some different types of network connections.

I used the "D" connect with the network nodes to allow the transport to leave one node and return to another when it is putting something in the rack. This connection type shows up as an orange line between the nodes.

The four nodes are used to define different directions of travel. This is required to make the transports travel all the way through the racks instead of turning around and leaving in the opposite direction as they entered.

Because you had set in your model that only one TE was allowed between the racks at a time I changed the traffic control's Traffic Control Mode to Mutual Exclusion and set the max number to 1.

I changed a few other things in the model but only to help illustrate that the three changes above were causing the model to work correctly. If you want to allow more than one transport in the model at a given time then there would need to be some changes made to the model.

Good Luck,
Brandon

Brandon,

Thanks for all of your help. I'd kind of started to think that I needed to go in this direction and started putting something similar to this together.

Thanks again,

Courtney

Here is another example of how this could be done.

It uses the reassignnetnode() command on the NN's OnContinue trigger to make sure that the transporter leaves the opposite direction that it came from, rather than using two different one way paths as in Brandon's last model.

It also uses traffic controls to make sure that multiple transports going into the aisle can only go one direction at a time.


A minor issue with this model happens when a transporter unloads to one of the racks, then is immediately given a task sequence to load an item from the same rack. He will go directly to that item even if it is behind him. The way around this would be tricky pass-to logic on the dispatcher to avoid this situation, but I didn't want to get that complicated for this sample model.

I have another question involving Travel Networks. This time I'd like to simulate a wider aisle that allows basically 2 lanes for travel. The limitations/specifications are as follows:

1- Once a forktruck enters the aisle it goes in that direction.

2- Forktrucks can pick items from either side of the aisle. (i.e. the first item may be on the right side and the second item could be on the left)

3- If 2 forktrucks are side by side within the aisle another forktruck cannot pass.

4- If a forktruck needs to pass another it can as long as the other side of the aisle isn't blocked by another forktruck.

5- Forktrucks can enter aisles at either end. (one enters one another enters the other and they're are traveling towards each other)

Is it possible to build such a network with Flexsim. If so, could someone point me in the right direction.

Thanks,

Courtney

Does anyone have ny tips or a solution to my problem above? If it's not possible to do with Flexsim that's ok, I'd just like a little feedback so that I can try coming up with a close approximation.

Thanks,

Courtney

Courtney,

It would be very hard to make an exact replica of the situation that you are talking about. If you were willing to break the path up into smaller sections then it could be done with either traffic controllers or by closing and opening paths with the node triggers.

If you weren't concerned as much with the visualization and were willing to make the assumption that two fork lifts could pick from the same spot at the same time, then it would not be nearly as hard to do. Then you could simply use one path broken into shorter segments with a limit of two fork lifts in any given segment of the path.

I hope that these ideas help. Let us know how you decide to takle the problem.

Brandon

Thanks Brandon! I think breaking it up and using traffic controlers will probably be the direction I head in.

Originally Posted by Phil BoBo

Here is another example of how this could be done.

It uses the reassignnetnode() command on the NN's OnContinue trigger to make sure that the transporter leaves the opposite direction that it came from, rather than using two different one way paths as in Brandon's last model.

It also uses traffic controls to make sure that multiple transports going into the aisle can only go one direction at a time.


A minor issue with this model happens when a transporter unloads to one of the racks, then is immediately given a task sequence to load an item from the same rack. He will go directly to that item even if it is behind him. The way around this would be tricky pass-to logic on the dispatcher to avoid this situation, but I didn't want to get that complicated for this sample model.

I really like the model you posted for this! However, I was wondering how you could keep operators from passing each other?

I'm trying to do exactly the same thing, model a 1-way very narrow aisle, and for the most part, this method works great! but if i have multiple operators going down the same lane, they go in the same direction but don't wait behind 1 another, and instead just go to the finish node after the task has been completed. (defeats the purpose of a narrow 1way when transporters can pass each other)..

I tried messing around with non-passing paths with virtual exits in between the nodes, but then i have the issue of the operators exiting from the same entrance they came into the aisle on. any suggestions??

[i hope this makes sense...]

In addition to setting your paths to non-passing, you could also test around with these things:

Try messing the Maximum Travelers at Node property on the network nodes.

Or try using Mutual Exclusion traffic control objects as well.