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Messages - Johannes @ Robots in Architecture

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16
Support / Re: KUKA|prc with ghpythonlib.components
« on: March 28, 2018, 11:03:33 PM »
Hello,
I'm still not a Python expert, but for .NET it will make sense to wait a bit longer. The next major release will have it's own component library, that you can easily call from .NET or Python. The Grasshopper stuff is then just very thinly wrapped around it.
That being said, I thought that Python had the possibility to work directly with components, as they are on the canvas? See https://stevebaer.wordpress.com/2013/12/11/ghpython-node-in-code/
In which case that should already work nicely today. Never tried it out, though.
Best,
Johannes

17
Support / Re: KRC 2 external axis causing program errors?
« on: March 28, 2018, 09:48:16 PM »
You should have got a sticker on the side that tells you the robot type - what does it say?
But it's of course possible that somehow robots and controllers got mixed up.

I'd recommend making a backup of the current setup before the re-installation. If you don't have the KUKA recovery stick, either install backup software on the robot or (better) connect the HDD to another PC via an USB adapter and use a software like Macrium Reflect to make an image.

Best,
Johannes

18
Support / Re: KRC 2 external axis causing program errors?
« on: March 28, 2018, 05:42:24 PM »
Hmm... I need to look into why this is showing up as a singularity, because it seems to be part of a PTP movement, where singularities are not a problem.
In general to avoid singularities, just adjust the posture (e.g. via status, or simply by changing the starting position) or for milling rotate the tool around its axis.
And base 0 is "hardcoded" as the robot's base, so I wouldn't change it (not sure if you can even change it).

Regarding the gear ratio, as I suggested before I would simply manually rotate your E1 by 360 degrees and check if it makes a full circle!

Best,
Johannes

19
Support / Re: KRC 2 external axis causing program errors?
« on: March 27, 2018, 11:37:24 AM »
Hello,

Well, the thing is that even if you have got a turntable, you might not always want to use the root of the turntable as your origin. But note that bases on a turntable are called Offset Bases, and you need to calibrate them as such. If it's not an offset base, then it won't rotate along with the turntable. I doubt that base 0 would work as an offset base, so calibrate a new offset base - you can use all 0 if it's at the center of your turntable.

Some more suggestions: The GEO input of the turntable is meant for the geometry of the object on top, i.e. it will rotate along with the turntable. At the moment we do not support custom turntable geometries, though we can integrate it as a native component for members.

And very important: The more triangles you have, the slower Rhino gets. Your turntable model has got 45k vertices, which is more than the entire robot. So your performance will get quite a hit.

I have made a quick example for you on how to calculate turntable values automatically. See here: http://forum.robotsinarchitecture.org/index.php/topic,822.0.html

Best,
Johannes

20
Tutorials / Example: Custom Turntable Strategy
« on: March 27, 2018, 11:35:28 AM »
Custom Turntable Strategy
Requirements: Rhinoceros 5/6, Grasshopper 0.9.0076/1.0, KUKA|prc V2

You can set up entirely customizable turntable strategies. This is an example based on the thread at http://forum.robotsinarchitecture.org/index.php?topic=817
Note that using a mesh for extracting the normal vectors might lead to a "jittery" robot movement if the mesh is rather coarse.

21
Support / Re: KRC 2 external axis causing program errors?
« on: March 23, 2018, 04:14:22 PM »
Yes, I meant mastering. All of that sounds fine, as a turntable is generally symmetrical it doesn't matter too much where the zero point is located at!

Maybe one more thing: Did you set the gear ratio correctly? That might also confuse the robot during the calibration.
EDIT: I guess you could check the gear ratio by manually jogging the turntable, to check if 360 degrees are actually one full rotation.

If that doesn't help I would try to enter the values manually, just to see if it works out. In your $config.dat there will be a line like that...
MACHINE_DEF[1]={NAME[] "DKP-400_1_40A_400V",COOP_KRC_INDEX 1,PARENT[] "WORLD",ROOT {X 7000.0,Y 0.0,Z 0.0,A 0.0,B 0.0,C 0.0},MECH_TYPE #EASYS,GEOMETRY[] "ObjectId = -1068536877"}
Set the XYZABC of the ROOT to the position of the turntable. Maybe leave ABC at 0 to start with. Then calibrate an Offset Base and see if it's synchronizing (with a little bit of drift).

Best,
Johannes

22
Support / Re: KRC 2 external axis causing program errors?
« on: March 23, 2018, 03:57:16 PM »
Hello,

It shouldn't matter whether it's levelled or not, after all the frame of the turntable is set in XYZABC, so just like a base it could also be tilted.
It's quite normal that the robot is shaking a bit when accelerating and decelerating during jogging, but while it's moving it should be a straight line.
When you calibrated the robot, did you use a calibration device (EMT/EMD)? Because it's not enough to just align the white marks.

Best,
Johannes

23
Support / Re: KRC 2 external axis causing program errors?
« on: March 22, 2018, 05:09:05 PM »
Hello,

You can quite easily check if something went wrong with the axes - simply test if the robot can move along a straight line. If it wobbles or deviates a lot you've got a problem, otherwise it shouldn't be in the vicinity of 300mm.
In general I'd say that most milling tools would shatter before the robot gets seriously damaged as they are quite brittle.
And is the tool calibrated correctly? I.e. if you move it in A, B or C the tip stays at the same position?

What you can also do, just for testing, is to guess the root point (move the calibrated tool into the center of rotation, display the actual position) and enter XYZ manually (is there a menu for it? otherwise in the machine data) while leaving ABC at 0.

...one more thing: When it asks you for a reference point, take the approximate distance from the center of the turntable to your calibration point as e.g. X.

Best,
Johannes

24
Support / Re: KRC 2 external axis causing program errors?
« on: March 20, 2018, 10:04:58 PM »
Hello,

Hmm... Strange. I'm more "fluent" with KRC4 so it's a bit hard to troubleshoot from away. I would recommend that you talk with KUKA first, and if they cannot really help you could send me the relevant machine data, so that I can compare it with a similar robot.

And if you program it manually, it might be that the axis movements are looking fine, but when you look at the Cartesian values they are all over the place.

Let me know what KUKA says!

Best,
Johannes

25
Support / Re: KRC 2 external axis causing program errors?
« on: March 20, 2018, 07:03:42 PM »
...and because of your username I somehow assumed you to be in Germany, which seems not to be the case. Sorry for that!
But if you or one of your colleagues DO speak German, I would still recommend calling the German KUKA hotline as it's free during regular office hours and they are very competent: +49 821 797 -1926
Have your robot serial number at hand, as they will ask for it.
I'm not sure how the technical support works in the US, but you can also give that a try!

Best,
Johannes

26
Support / Re: KRC 2 external axis causing program errors?
« on: March 20, 2018, 06:59:54 PM »
After reading your post again - you already cannot calibrate the root point due to an error message?
Does it fail at the end, or at the beginning of the process?
In any case, you should definitely check with KUKA or whoever set up your robot. Probably it's just a single wrong value somewhere.

Best,
Johannes

27
Support / Re: KRC 2 external axis causing program errors?
« on: March 20, 2018, 06:56:49 PM »
By teaching I mean that you "manually" program the robot - so called online-programming, where CAD is offline-programming. So rather than going through Grasshopper you create a new file on the KCP, move the robot somewhere, save it as a PTP movement, move it somewhere else, save it as a LIN movement, always with different values for the external axis. The robot should then be able to replay the movements exactly like you programmed them (relating to the positions, in between it will interpolate according to the movement type).
If that is working while PRC is not working, can post the DAT and SRC files?

Best,
Johannes

28
Support / Re: KRC 2 external axis causing program errors?
« on: March 20, 2018, 03:45:14 PM »
Hello,

But is it synchronizing properly, as per my previous post?
I don't think it's related to the tool orientation, that should not influence it.
Can you simply teach the robot positions that involve a change in the external axis? If that also does not work, I would just call the German KUKA hotline. I guess then it's just a small configuration issue.
If that works, and the KUKA|prc file does not work, please send me the *.src and .dat file from the program (which you manually programmed at the robot, not the PRC program).

Best,
Johannes

29
Support / Re: KRC 2 external axis causing program errors?
« on: March 19, 2018, 09:41:46 PM »
Hello,

I may be wrong there, so please double-check, but to my knowledge you can only use KUKA motors (or let's say motors attached to a KUKA PowerPack in the cabinet) to drive a turntable synchronously.
Otherwise the E1-E4 values will simply be ignored. In your case I guess that you are controlling your external axis through maybe an analog output or serial commands to a controller? Or have got a servo driver at the bus coupler?
In that case you can set the rotation value e.g. through a Custom KRL command, but you will need to rotate your frames yourself in Grasshopper. At least the calibration should be easy, you can simply do that same as if you calibrate a KUKA turntable but write down the points. With the three points you can create a circle in Grasshopper, and the center is your rotation center and the circle's normal the rotation axis.

Best,
Johannes

30
Support / Re: Plasma cutting...
« on: March 18, 2018, 05:15:58 PM »
That's the event in Beijing: http://www.caadria2018.org
You'd be very welcome to join the workshop, I think they charge 4k CNY, though.
My colleagues at IP RWTH are the experts with the plasma cutter ;)

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