KUKA CNC _ Spline and Circ Movements

[jason_r_Crow]

When exporting KUKA CNC, are the Spline and Circ movement components supported? The g-code I am getting doesn't create a G2 or G3 command, it just tells the robot to go to a given point.

[Johannes @ Robots in Architecture]

Good Morning Jason,

I need to take a look at the code later, but I believe that we deactivated CIRs at some point because there were some issues with it.
If there is a need from your side, I can allocate time to try to get them to work again. KUKA.CNC is quite a niche product (and marked with "Beta" in the settings) so there are some features missing.
That being said it has been improved in the past months because there are now a few more users around with requests etc.

If you have got some working code snippets of G2/G3 in KUKA.CNC implementation that would also speed up the process!

Best,
Johannes

[jason_r_Crow]

Hi Johannes,

Sorry for the delay: Wednesdays are my robot days. :)

Ah, yes, that makes sense in terms of the behaviour that I am seeing. CIRCs just become points in the gcode. SPLINE movements might be ok, too. I would be more than happy to play around with things and see what I can make work relative to G2 and G3 commands, if you can reenable both for the Kuka.CNC code output.

Jason

[Johannes @ Robots in Architecture]

Hey Jason,

No worries. I've already prepared my code for CIRCs and SPLINE, so theoretically it should be quick to implement.

I'm still a bit worried about the syntax as I cannot test KUKA.CNC at my setup, so some tests here would be great. I've got the programming manual from ISG Software, but it is not robot specific and most examples only use three axis.

G02 and G03 are clear, I would probably also have to set G161 to set the auxiliary point in absolute coordinates. What I'm not sure about is how to best implement arbitrary arcs, as the arcs seem to be always in relation to one of the three planes (via G17, G18, G19).
The challenge with splines is that the default B-Spline settings works with control points, while the robot creates a spline that goes through the points. So I would have to set it to Akima interpolation, which will be a bit different from the preview.
I'll have to check if an Akima spline with three points approximates an arc with the right tangents or not. That could also be a workaround...

Any ideas on that? Maybe I'm misunderstanding things here...

Best,
Johannes

[jason_r_Crow]

Hey Joh!annes,

Cool! At least most of what I am doing will be with circle segments. I am working on replicating some of ways in which Borromini approached the geometry of domes, so similar to the scripting Cameron Wu does, but in three dimensions. None that requires a spline. That means if the arc has to be on one of the planes, it could get tricky to come back and have an arc-like movement normal to the surface at a point, correct? My colleague is much better with g-code than me, so he might be able to help more than me. Regardless, I am happy to assist with testing and figuring things out.

Using Akima interpolation for the splines seems like a good compromise. I guess the thing to test would be to see how different the actual movement is from the preview? Mostly the preview is just acting as a 'not doing very, very bad things' check for me :D, so close enough might be fine.

Jason

[Johannes @ Robots in Architecture]

Hello Jason,

Shall we continue the discussion with your colleague in CC via eMail? May be easier than the forum!

Best,
Johannes