Problem with pick offset with a crane

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Patrick Zweekhorst asked Oct 4, '17 Phil BoBo edited Oct 5, '17

Problem with pick offset with a crane

Hi All,

I have a question about the pickOffset task I am giving to a crane. The tasksequence I am using is:

Object crane = model().find("Crane1");
Object destination = model().find("Queue1");
Object item = destination.first;
treenode TaskSq  = createemptytasksequence( crane, 0, 0 );

//X Y movement
inserttask(TaskSq, TASKTYPE_PICKOFFSET, item, destination, 1, 1, 0, 0);
dispatchtasksequence( TaskSq );

The problem that I have is that the crane does not end his movement on his travel height. He stops at his start height + the height of the item. I did not expect this because I am saying that the crane should not travel offset in the z direction. I expected that the crane would stop at height 1, not 2.3. Is this behavior correct or not?

Thank you,

Patrick

Attached is a simple model, where you can use the script to start the tasksequence.

Software Version:

Flexsim 17.1.6

crane tasksequence pickoffset

cranemovement.fsm (16.6 KiB)

Answer 1 · 2017-10-04T17:56:59Z

Phil BoBo answered Oct 4, '17 Phil BoBo edited Oct 5, '17

The item's height is added to the offset location after the pick offset scale factors (var1-var3) are applied to the offset location.

This gives the undesirable side effect that you are seeing with the crane and a 0 z scale factor, but it is none-the-less how it was designed to work. Whether that is a good design or not is debatable, but that's how it works.

The best way to get around this behavior in the cases where you don't want it, such as this one, is to use a travel_to_loc task instead.

This movement is part of the Drop Hoist section of its Travel Sequence, so you could adjust the Travel Sequence as a workaround as well.

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