# Fanuc position register and offsett

• Hi guys, I work at a Inside and outside Car mirror facility, Magna Mirrors. We use the robot to test inside mirror ball joints, imagine you keep rotating and moving your inside mirror in different positions. Anyway, I have the mirror mounted in the car position on a fixture and I teach the first point and then I do position offset 15 degrees, up down left and right direction. I make sure to select the correct tool number and i make sure it rotates around the axis of the ball that the inside mirror rotates on. I always have to retouch the position cause the robot cage is on wheels and the robot sits inside a chamber so it is never consistent. Sometimes when I teach it, the robot rotates around the axis perfect, sometimes the robot starts moving different directions instead of just 15 degrees left right up down direction. I am not sure what I am doing wrong, I thought the robot would rotate around that position register no matter what I do. I hope I am making sense

• Hi

I need to know if you have any UF defined. Could you post your program ?

You said sometimes works and sometimes doesnt ? Are you close to singularity ? Are the PR configured the same ?

Retired but still helping

• I bet when he Touches up the points after the robot has moved, he is not making sure the proper User frame is selected in the Jog Menu.

Reteach the program, and make sure all PR's are relative to the robot (UF 0).

Or teach the points of movement as regular points (P[1]...P[10]) and use the PR as a "Start" position. so you will have some consistency after the robot has moved.

You have to keep something the same every time. either the program, or the root starting position. Preferably you want the robot to stay in the exact same spot every time, bu it sounds like that is not an option.

• so I am making sure that my PR are the same and the tool frame is the correct one. I think the singularity point is correct, I am getting elbow or wrist singularity. I'm trying to figure out what that exactly means and how to avoid it altogether cause I know if I move it just a little bit in the right spot, it works like it should.

• so I am making sure that my PR are the same and the tool frame is the correct one. I think the singularity point is correct, I am getting elbow or wrist singularity. I'm trying to figure out what that exactly means and how to avoid it altogether cause I know if I move it just a little bit in the right spot, it works like it should.

If you're near singularity just jog J5 a few degrees. If possible, and necessary, use Joint moves when you're close to singularity instead of linear moves. Also if I read your original post correct, it sounds like you're trying to use a fixed PR to accommodate a part that is never in the same spot or rotation? If that's the case you might need to use some sensors or a camera, or use Skip condition search with a sensor on the robot to determine part orientation and location. I am using a Keyence LR-Z CMOS photo eye sensor to determine part location and orientation right now on a project. It works pretty well aside from adding cycle time to search for the part.