Mismatch Position for Kuka IIWA

Started by z5113452, August 09, 2023, 03:45:26 AM

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Hi All,

Hoping someone can please help me out a little, I am trying to program an IIWA, and when I add in a start position or even use the axis command component, the position of the robot in the simulation is completely different from the physical position, even though all the axis data matches. I haven't added a base or set up any programming for the 7th axis (maybe this is the problem?)

Any troubleshooting ideas are welcome - it has been a long time since I have worked with an IIWA....

Johannes @ Robots in Architecture


KUKA|prc uses the "old" KUKA system from the pre-iiwa LBR-series where A1-A6 are used as per the "normal" 6-axis robots and E1 is the redundant axis between A2 and A3.

So you can map it like that:

iiwa vs. PRC
A1 = A1
A2 = A2
A3 = E1
A4 = A3
A5 = A4
A6 = A5
A7 = A6

You can enable the E1 input by right-clicking movement components in Grasshopper.
Also, take care that the iiwa internally works with radians. That is not a problem when you are using purely KUKA|prc as the conversion is done internally, so I'm mentioning it just in case.



Ah I see, thankyou! Is there a method or example of this mapping in grasshopper? Or are people doing some sort of post-processing?

Johannes @ Robots in Architecture

Because the KSS and Sunrise implementation share an UI, this is unfortunately a compromise that we had to make.

So when you enter axis values you have to keep that in mind. That being said, the redundant axis is mostly important (in my experience) to enhance the reachability of the robot, so often you don't have to really touch it anyway.

We're aware it's not ideal and are implementing ways for better supporting different robot types in a future major release of the software.