IIWA - Kuka PRC CIR Movement Point Order

[jason_r_Crow]

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:

Code Select Expand


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

and change it to...

Code Select Expand


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

There should be two occurrences of that line.

Best,
Johannes