Confusion about the tool coordinate system

[mernestus]

Hello,

I was just confused about differences in the way the tool coordinate-system is defined because it seems to be different in KUKA|prc and in the actual Kuka robot:

• In KUKA|prc the z-axis seems to be pointing into the toolhead (see e.g. attached screenshot of the Elte Spindle) and toolpath utilities like "Divide Curve" only work properly if the tool head coordinate system is aligned in such a way.
• The Operating and Programming Instructions for System Integrators tells me (on page 91), that the x-Axis should be pointing out of the toolhead (see second attachment).

Now I set the coordinate system for my custom tool head in the way that the Kuka Manual told me and did the same thing on the robot controller side and it worked nicely. But as a workaround I need to construct all the linear movement commands on my own without the convenient utilities.

My guess would be, that it is OK to define the coordinate system in one way on the robot and in the other way in KUKA|prc and it should work (I did not test it yet). Is that really the way to go?

Best,

M

[Johannes @ Robots in Architecture]

Hello,

The robot itself does not care which tool-axis is being used, but how we are handling it in KUKA|prc is indeed a bit non-standard - initially (long ago), coming from a KUKA SIM and CAMRob background the goal was to have a spindle with 0/0/0 for ABC be vertical to a frame. So we're basically using the X-axis as the toolaxis.
There is a "hack" to have KUKA|orc use the Z-axis, however it will make problems if you share definitions with people who use the regular version.

However, you definitely do not need to use different tools with different ABC values or so. Either calibrate the tool for the right tool axis, add the extra rotation numerically, rotate the frames in Grasshopper, or use the hack to set it to the Z-axis. The simulation and code generation follows the KUKA-standards, the only difference is how KUKA|prc interprets the frames coming from Grasshopper.

Best,
Johannes