IIWA - Kuka PRC CIR Movement Point Order

Started by jason_r_Crow, March 15, 2021, 05:03:31 AM

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I am seeing a disconnect between the simulation and the movement of the IIWA movement when attempting to draw multiple circles.

When creating a CIR movement on the IIWA, my recollection of the proper point order to pick is start (point 1), end (point 2), aux point (aux point).

In Kuka PRC, if I input that point order, the simulation does not show the correct movement, but if I input the points as start (point 1), aux (aux point), end (point 2), the simulation looks correct.

On the robot, the opposite happens. If I input the points as start (point 1), aux (aux point), end (point 2), the robot back tracks when repeating the arc movement to form circles.  If I input the points in the order start (point 1), end (point 2), aux point (aux point), the robot moves correctly.

Johannes @ Robots in Architecture

Hello Jason,

That's pretty strange, especially considering that we definitely did use CIR movements in a few of our projects - but that was also a few software versions ago, so who knows what changed. But the behavior in KUKA|prc should be to provide three planes, out of which the start, aux, and end planes are generated. I don't have an iiwa anymore so I cannot test that myself, but if you want to switch the frames you need to look at the following sections of the PRC_CORE.java file:

AbstractFrame frm = cmd.cirMove.frame;
AbstractFrame auxfrm = cmd.cirMove.auxframe;

and change it to...

AbstractFrame frm = cmd.cirMove.auxframe;
AbstractFrame auxfrm = cmd.cirMove.frame;

There should be two occurrences of that line.