I am trying to develop a model that essentially shows the movement of material in the warehouse.
I want the rackstore block to move multiple boxes at a time in the rack using crane. In the current model, crane takes one box at a time, stores it in the rack and comes back to take next box.
Not sure if RackStore supports that, but as always, you can find a solution in AnyLogic.
One simple fix: bundle your packages together into 1 agent using the batch object. Then, they stay together until being taken out by the crane at the end (via RackPick) and you can un-batch them to their original agents. Have a look at some example models using batching.
cheers
Depending on the details of your model, one option is to use batch as Benjamin stated, but I think I feel the pickup dropoff blocks would work better because with the dropoff you can drop the boxes one by one, while the batch forces you to separate all the boxes at once...
So with the rackstore you can't do this, but if you use the pickup and then dropoff, you will have to store somewhere in your model what rack positions are free though, because when you move the crane you will have to choose the rack position yourself, while the rackstore does it automatically...
Nevertheless, the batch may also work... it depends on the details of your model
Related
I hope you are having a great day.
Recently, I tried to build an AnyLogic model with free-space transporters, but I encountered an unexpected situation as shown below.
I thought that there is no logical reason why all the transporters are jammed in a specific position. Is there any solution or possible reason for this situation? I have attached my model for your information.
Thank you for reading this question.
The problem with the traffic jam appears to be due to the fact that there are two few attractors available for the transporters to place the items and then they get stuck waiting for an attractor to become available...
When running your model as-is I get a jam in the stage one area
And in the logic blocks, I can see that the transports are stuck in the "Move By Transporter" block.
If I assume the attractors are set to 4 for a reason I would suggest the following logic - similar to what is described here
You create a list of all the attractors available. See the neat trick in AnyLogic where if you select a bunch of objects and then right-click on them you can automatically create a collection.
You can call it something like attractorsAvailabeStage1
And create a new map to store the WIP agents that will be occupying the attractors
And have a function that will provide the available attractors.
Change the move by transporter option to move to an attractor
And also return the attractor as available once it gets moved from its location
Now you only need to prevent mew agents from entering the area if there is no more attractors left or agents on their way to the attractors
I tested it and it works great for stage 1 you need to do it for all the stages.
On second thought....
seeing that you do have resource pools and service blocks. You can achieve the same logic I described by having resources first size the locations, then go to the transport block, and then be delayed
You first seize the space in the stage, then you move to the space, then you delay it.... then you wait, then seize the space in stage 2, then move there, then release stage 1.
I would go for the latter option
I'm developing a project with Anylogic and I have an AGV with a Kuka cobot on top of it (a sort of mechanical arm used to pick item from a shelf, in this case) which should pick some items from a rack store. I would like the cobot to pick more than one single item at once.
The blocks I already put are shown in the picture and I thought that specifying "seize whole set at once" in the rackPick block would have helped but it did not.
Could you help me, please?
Thank you in advance.
The RackPick logic is agent-centric, i.e. the items in the rack are the active entities. They, essentially "pick themselves", optionally using your robot as a help.
So if you want your robot to pick several, it is best to batch your agents together before putting them into a rack (using Batch) and then let your robot pick that batch agent. You can unbatch into the original agents afterwards.
PS: That "seize whole set at once" option is again from the agent perspective: if it would need several resources to be picked, then this option would have an effect. In your case, with only needing 1 robot, it is meaningless
I have in my model some free-moving agents, which travel to specific nodes. I use the function...
moveTo(node)
...to specify the node an agent should visit. Using this function, the agent travels the shortest path to the node. However, the model layout contains areas (i.e. image files), which the agent should not pass. Right now, the agents may travel through these areas to reach their destination. Now I'm wondering, whether there is an easy way to permit an agent to enter specific areas in the model, when traveling to a node.
I already took a look at the example model "Wandering Elephants" where the elephants are permitted to walk through areas with water. The solution there is, that if an elephant meets water in the direction it's currently heading, it randomly searches for another direction, until it finds one without water. However, this approach doesn't really fit to my problem, as the elephants in the model wander around without any specific destination. I'm searching for a method, which works for an agent that travels to a specific point. In the best case, the agent would search the shortest path around the obstacle to reach its destination.
Edit 1: The following figure shows my problem in a nutshell. On the left side is my model structure, while on the right side the state chart of my custom agent. What is happening in the model: The 3 sources are producing agents, which will be delayed for an uncertain time (delay stops with stopDelay()). Everytime an agent enters a delay, the delay is added to the collection request. My customagent check requests in a loop until the collection contains at least one request. Then, the customagent randomly selects a request (i.e. delay object) to serve. Each delay is associated with a node (the collection processNodes maps delays to nodes). Now, I want to cast my customagent to a Transporter and move it to the corresponding node. The agent should avoid collisions with the stripped walls in the model. I want to avoid any seizing and releasing of resources. I just want to adapt the behaviour of the Transport agent from the material handling library to my agent.
Edit 2:
In my current testbed, my custom agent does not consider node 1 or node 2. For testing, the agent should only try to reach node without any collisions.
I found a sufficient work-around. Not exactly what I wanted, but it works. Against my initial intention, I use now seize and release for transports. However, I added a hold-block in front of each seized-block and only a resource, which decides to serve the process, is able to unblock the corresponding hold. The on-enter control of the unblocked hold ensures that the hold is directly blocked again as soon as a single agent flows through. For the case that other users are also interested in the solution, I attached the flow-chart of the process and the state-chart of the Transporter-Agent. The system structure is quite the same as in my initial question.
There is no build-in way unless you use transporters from the Material handling library (or pedestrians). These can do what you need.
So easiest might be to convert you agents to transporters temporarily.
Otherwise, you will have to code something yourself...
In the example above I present an example anylogic process flow, excuse me for the link as I'm not allowed to upload pictures yet.
In this flow, is it possible to stop the source from sourcing if the rack system is full or filled to a certain level? (under the assumption that both rack picking and storing is done in that rack system.)
Sure, you can always switch a source off. It depnds on how you defined the arrivals in the source, but for a "Rate" and "Interarrival Time" source, you can use:
mySource.set_rate(0);
All you need to do is to call this in the correct point in your model, i.e. when the rack system is full. To do that, you might need to write a function isFull that loops through all its rows, positions and levels and tests myRackSystem.isFree(row, position, level). If everything is full, you stop the source from creating more stuff.
I'm am storing agents two deep in a single pallet rack with a rackStore block. When I take items out of the rack with rackStore it tries the take the agents at the back first and I get the error below saying it couldn't be picked as there are other agents in front of it.
Anyone know how I can pick from the front instead?
This is big fail in the AnyLogic Software and it is something they have to fix urgently. Since when it comes to deep positions, you have to control everything manually.
I will give you an example that is definitely not optimal on how to solve your particular question and it will be just a step for you to understand how to extend it to something more than this. Because even though this should be a very easy question, it is not. This will work only 2 racks with 2 levels deep, 1 level of height, and a unique row.
So this is the structure you would need:
Since I have no idea how long your products stay on the rack, I will assume something, which is that with the event, I will make the decision on wether getting or not a product from the rack every 5 seconds (this is absolutely arbitrary).
You will need a custom agent to store the deep position. I call the agent Box and I will have a population of boxes. Not in the picture that I also add agents to the custom population boxes.The box agent will have 2 variables: deep and position which will store the position and deep level of the agent in the rack (you will need also level and row if you have a more complex rack)
Now on the event, which runs cyclically every 5 seconds, I have the following action: (it activates if there is a box waiting, if there is a resource available and if there is no forklift moving a product to the pallet rack) I have to do this because I cannot know where the forklift is going to put the box until the box is already in the pallet rack. Then I check if a box is not behind another with the findFirst function and if everything ok, a box is sent to be picked.
if(wait.size()>0 && resourcePool.idle()>0 && rackStore.size()==0){
Box bx=findFirst(wait,b->b.deep==0);
if(bx!=null)
wait.free(bx);
}
On the rackStore exit I need to store the positions so in the "on exit" action, this code will help (you check if there is another box in the same position, and if there is, you update the value of the deep variable. Then you store the value of the position and deep of the new agent)
Box box=findFirst(wait,b->b.position==position);
if(box!=null){
box.deep++;
}
agent.deep=0;
agent.position=position;
Finally on the rackPick on exit action, once the product is picked and delivered, you update the deep value of the box that was behind it (if any)
Box bx2=findFirst(wait,b->b.position==agent.position);
if(bx2!=null){
bx2.deep--;
}
I know all this looks a bit crazy, but you have to create all the logic yourself when it comes to using deep levels...