Robots in Architecture Forum

KUKA|prc - parametric robot control for Grasshopper => Support => Topic started by: EKing on June 17, 2018, 03:40:26 PM

Title: Custom Turntable for 3+2 style milling
Post by: EKing on June 17, 2018, 03:40:26 PM
Hello Forum.
I am following videos on how to use the turntable function with PRC but these assume a KUKA generic turntable.

I would like to get a rotary axis as an external axis and use it just for positioning the work piece between KUKA milling movements.
Are there any tutorials that would show how to assign a custom geometry to an external axis and how i would generate code to position the work piece between kuka movements?
Something like: do typical prc movements... then stop... spin rotary axis... then continue PRC movements?
thanks!!!
Title: Re: Custom Turntable for 3+2 style milling
Post by: Johannes @ Robots in Architecture on June 18, 2018, 10:11:53 AM
Hello,

So you want to build your own turntable, right?
In that case I would program everything in KUKA|prc as if there was a turntable attached (show external axis values by right-clicking the component).
I haven't tested that before, but I think you can set up a virtual turntable, in which case you are done and can proceed to the next step. Because then your base (calibrated as an Offset Base) is rotating with the turntable.
If not, you need to geometrically rotate your planes around the turntable axis. I.e. you use the normal setup from E1-E4 to simulate it, but for the code generation you take a second version that rotates the planes accordingly.
I've attached a quick example that you could e.g. turn into a cluster that can be switched from generating geometry for an actual or a "fake" turntable.

If there isn't a turntable attached, the KUKA will simply ignore the E1-E4 parts, so you can leave them in.

Before every change of the turntable axis, I would put in a Custom KRL like this

;Turn turntable to xx degree
HALT

So if you are manually turning the table, just look at the comment, or if you are using a motor (i.e. not a genuine KUKA motor) then you could set a value to an analog output or a series of digital outputs instead of the comment.
Once you have a feeling for the timing, you could replace HALT with WAIT SEC xx to give the motor sufficient time to reposition. After HALT you need to press the start button to resume.

Best,
Johannes