Model problem

[dawikra405]

Hello,

I have just started using ED and I have to model a simple system with two servers ( CNC turning and milling) and robot. The robot should realize the following motion tasks:
1- from conveyor to server1,
At this time robot have to change a gripper (atom queue2) and pick up the workpice:
2- from server1 to queue1 ( using as reorientation table and temporary storage)
3- from gueue1 to server2
At this time robot have to change a gripper (atom queue2) and pick up product to:
4- from server2 to conveyor and sink.
I hope I explained this properly.
I'm beginner and I have no idea how I can do it. How do I go about writing a script for this. I will be grateful for help.
Thank You
Kind Regards
David

[MarvinH]

Hello David!

You can connect the channels of the elements in such a way that the product follows the desired route. In your case, the connections will be as follows:

- Output channel 1 of conveyor1 to input channel 1 of robot;
- Output channel 1 of robot to input channel 1 of server1;
- Output channel 1 of server1 to input channel 2 of robot;
- Output channel 2 of robot to input channel 1 of queue1;
- Output channel 1 of queue1 to input channel 3 of robot;
- Output channel 3 of robot to input channel 1 of server2;
- Ouput channel 1 of server2 to input channel 4 of robot;
- Output channel 4 of robot to input channel 1 of conveyor2.

OnEntry of the robot, store the input channel that triggered the entry by the command "ic(c)" on a label on the product. This is needed to determine where the product has to be sent to next. So when the product enters from channel 1, it will be sent to channel 1, etc.

This is the easy part, which I have implemented in the attached model. The difficult part is the control of the robot. For example, what to do when there is a product at the end of conveyor1, but server1 is already processing some job. In case the robot will pick up the product from the conveyor, then the system will be in a deadlock, because the product from the server has to be removed but this is not possible as the robot is already occupied with the product from the conveyor.

You have to think about this control and the priorities of the orders. If you know this and don't know how to implement it in your model, please return to this topic again.

Considering the change of a gripper, I would only model the time required to change a gripper, this can be done by incorporating a load (or unload) time for particular actions. This way the robot is not available for new tasks (as you want to model), but it does not have to actually pick up a product.

Good luck!

Kind regards,

Marvin

[dawikra405]

Marvin,

Thanks for the reply. I try to explain my problem once again.
You make me realize that this is a very difficult task. I read the tutorials and I can not find anything. I would like to implement the following process:
The robot takes the product from Conveyor1 and pick up to server1, then the robot has to change gripper and moves workpiece from server1 to queue1 (reorientation table and temporary storage). Then the robot returns to basic gripper and moves next product from conveyor1 to server1. When the server1 is processing, robot changes gripper and moves workpiece from queue1 to server2. When the server2 is processing, robot moves workpiece from server1 to queue1. At this time workpiece in server2 is finished and robot transports finally product to conveyor2. In this way system creates new products.
To some up, system contains:
- Two grippers- basic for raw material and special for partially finished material (workpiece )
- Two servers
- Two queue- queue1- reorientation table and temporary storage), queue2- grippers magazine
The Robot has to realize the following sequences of motions:
Conveyor1- Server1- Queue2(change gripper- SPECIAL)- Server1- Queue1(reorientation table and temporary storage)- Queue2(change gripper- BASIC)- Conveyor1- Server1- Queue2(change gripper-SPECIAL)- Queue1- Server2- Server1-Queue1-Server2-Conveyor2-Queue1- Server2 –Conveyor2.
I have no idea to realize this process. I thought that the robot moves the product to all stations but it’s uneconomical because the server1 doesn’t work when the robot takes a workpiece.
I have no idea and serious problem. I can not write a script for this process.
I will be grateful for any help and advice.
Kind regards
David

[MarvinH]

Hello David!

In my opinion the model I posted previously almost realizes the sequences of motions you described. The only motion that is not included is the change of gripper, which I explained before. When you incorporate the time needed to change the gripper, then the actual move of the robot is not necessary. You can do this by defining a Load time or Unload time. You can refer to the product (for example to determine where it is coming from) by i.

Further I suggest that you have a look at the InStrategy of the robot. Have a look at the different pre-defined strategies, and determine which strategies you can use to create the desired sequence. When you click on the small box right next to the description, you can see the script that is executed. Maybe you can have a look at these function with the help of the ED help file (press F1).

Finally you are right about the fact that the server1 does not work when the robot takes the workpiece. You can solve this by putting a buffer (queue) in front of server1. The products moves from the conveyor to the buffer by the robot and from the buffer to the server1 without robot. This way, when the robot takes the workpiece from the server1, a new workpiece is loaded from the buffer automatically (i.e. without waiting for the robot).

Good luck!

Kind regards,

Marvin

[dawikra405]

Hi Marvin,

Thanks a lot for your answers. I had to stop working in my model but today I would like to return to problem and refresh this topic.
Nowadays I want to build a system with robot and servers. The system should work in paralel event:

Robot picks product from conveyor and feeds Server1. Next Robot picks product from conveyor and and feeds Server2.
Then Robot returns to Server1 and moves product from server1 to Turntable and come back to Server to finish other side of product. Next robot goes to Server2 and executes that same procedure (server2-turntable-server2). Then Robot picks product from server1 to conveyor and from server2 to conveyor and finally two products leaves system.

Firstly I solved the problem of deadlocks when servers work. I've stopped source when two products leave this atom.
I have a problem because I can't realize this route. I tried to use the node atom but it doesn't work. I tried to use label of products and properly connect input and output channel all elements. But this way was wrong because I couldn't assign robot for this route.
I enclosed my model. It contains what I tried doing.

I've thought about it and I have no ideas and I'm not capable to finish it. I would like to ask you about help for me. Any ideas and advices will be helpful.

Kind Regards

[dawikra405]

HI,

Any ideas for this problem ? help me, please

Kind regards

[vincent1989]

Hello David,

I've taken a look at your problem.

By giving the products for each step a label noting which steps are completed we can control the process.

Thus Product 1: source -> conveyor -> crane -> server1 -> (step 1 complete) -> crane -> turntable -> (step 2 complete) -> crane -> server 1 -> (step 3 complete) -> conveyor -> sink. Product 2 = same (server2)

Each time the crane reads the labels of the steps that are completed and subsequently sends the product to the right output.

The only problem remaining was that product 2 had to wait for product 1 to be finished with the timetable (else the model would get stuck). I've solved this by closing the output channel of server2 at entry and opening it when product 1 is done with the 3rd step.

My model can be found in the attachement

Regards,

Vincent.