Author Topic: The robot desn't work in the same way in the simulation.  (Read 9706 times)

Johannes @ Robots in Architecture

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Re: The robot desn't work in the same way in the simulation.
« Reply #15 on: September 27, 2017, 07:15:25 AM »
Hello,

It took me a bit to unlock your post, as I'm currently out of the office - sorry for that!
You've got three planes for the CIRC movement - can you quickly test if you get the same XYZABC values in the SRC file for both LIN and CIRC movements? And if so, check if the robot moves differently (except the interpolation being linear/circular, of course)?

Please let me know how it works out!
Best,
Johannes

R.Staunlich

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Re: The robot desn't work in the same way in the simulation.
« Reply #16 on: September 29, 2017, 09:56:18 AM »
Hello Johannes,

thanks for the quick answer. I am a little busy at the moment, but I will check that...

But the main intention was not to create a circular movement. The was just due to simplicity.
I would be happy if I had a single linear movement from one point to another withot B-rotation.

Regards

Johannes @ Robots in Architecture

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Re: The robot desn't work in the same way in the simulation.
« Reply #17 on: September 29, 2017, 06:41:47 PM »
Just to be on the safe side, are you 100% sure that the XYZABC values match between simulation and the robot? I.e. you are not using a template tool, but a Custom Tool with (more or less) exactly the same XYZABC values as you calibrated at the robot?

Best,
Johannes

R.Staunlich

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Re: The robot desn't work in the same way in the simulation.
« Reply #18 on: October 01, 2017, 06:37:23 PM »
Well, the real robot is out of scope at the moment.
My problem /my (mis?-)understanding is as follws:

1. The Grashopper Lin. Move-Command gets a plane as input.
2. This plane has a normal-vector (blue z-axis) that defines an axis-system positioned in rhino world-coordinates.
3. Rhino origin (0/0/0) is identical to the origin of the robots selected base-coordinates.
4. Inside the Grashopper Custom Tool settings I define origin & orientation of the tool's axis-system in relation to the robot's wrist.
--> Problem No. 1: if I leave the A/B/C-rotation unchanged (=0), the tool-axis system shown in Rhino (Z-Axis facing up) differs from that shown in the custom-tool dialog (X-axis facing down).
(see screenshot in the attachement).

5. Now I generate some simple linear movements by projecting curve-points to a plane. Normals of the planes all facing upwards parallel to Rhino world Z-Axis.
6. Simulation works well, Tool-Z-axis is in line with position-plane-Z-axis. No rotation at all. A/B/C = 0 (in Rhino world or robot base resp.).
--> Problem No.2: there is a constant 90°-rotation around B-axis in the generated Kuka-Code. It seems like the Lin.-Move command is taking the X-axis of the positioning plane as tool axis reference.
(see screenshot in the attachement).

Johannes @ Robots in Architecture

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Re: The robot desn't work in the same way in the simulation.
« Reply #19 on: October 02, 2017, 07:58:29 AM »
Hello,

Your process seems to be fine. As you have mentioned, KUKA|prc is using X as the tool axis - it can be changed to Z through an undocumented setting, but is not recommended.
However, no matter how the tool axis is set, the simulation and the movement of the actual robot should always match. It can only match if the tool and base values are the same, see http://forum.robotsinarchitecture.org/index.php/topic,115.0.html
So first you enter your tool XYZABC values in the Custom Tool and check the simulation. If the tool axis if off, you have got two approaches:
You either calibrate your tool for the X-axis, or you rotate your planes.
I wouldn't recommend using different tool values (e.g. always B + 90°) in the KUKA|prc Custom Tool and the actual robot as you have to constantly remember it whenever you make changes.

Hope the clears it somehow up!
Best,

Johannes