Collision and jumping steps

[ScreaminSteve]

Good afternoon;

I hope someone can give me some suggestions. I am using the nx controllers on a line with 15 robots. When there is a fault, we are able to reset the fault on our hmi's. The problem that we see happening is that if there is a collision fault on the robot and it is reset, it will sometimes skip the move that it is currently in and go to the next move. This of course causes problems if there happens to be a clamp in the way of going to the next move. My understanding is that most other robots will slowly move back to the beginning of the move and then restart, thereby eliminating that problem. Any suggestions on a Motoman.

[mymotoman]

May I ask what kind of job does this line of robots do?

What we normally do is to reset all robots to the work home pos. and restart the job from the beginning (ie. press tending robots)

[Fabian Munoz]

Hi

1) Did you consider a recovery program for those particular points ?


2) Example (lets work in two dimensions, easier for my brain)


Point A (10,23)       Point B  (10,35)         Point C (10,42)         (x,y) in mm

If you collided at (10,36) even if you go back to Point B is not going to do any good to you, because is going to go backwards 1 mm and then move to Point C
If you collided at (10,35) is not "skipping"  B when it goes to C, because that what it suppose to do.
If (last if) you collided at (10,30) Can you really go under any circumstances on any of your 15 robots to Point A ? My answer is my point 1)

3) I don't know about Motoman and the moving back slowly to the beginning of the move. I don't think is standard, might be a parameter. Me, in particular, I always disable them in Fanuc and ABB. I don't find that function useful, it's slow and going backwards doesn't necessarily means SAFE

[tony gast]

Motoman robots  just continue after alarm reset.....Is the robot being moved to recover (by the operator)?....if so there is a parameter and or proceedure to recover

[ericm115]

Download the Operators Manual for Handling from http://www.robot-forum.com/robotforum/manuals_software_and_tools_for_motoman_robots/nx100_operators_manual_for_handling-t429.0.html

Pages 9-6 -> 9-8. I think you are looking for S2C324. The default value (0) is that the robot will continue to the next point from wherever it ended up after the collision. You want it to go back to the original path. I think you want S2C324=1.

Also, if you robot goes from points A->B->C, and it "rounds the corner" near B, then when it has reached 50% of the rounding curve, it considers point B reached. If something interrupts it, it will resume by going straight to point C. Usually this is sufficient. I think you may want to extend this further to 75 or 80%. This parameter is in S2C516.

I'm not an expert on these parameters though, so if I'm misinterpreting them, someone please correct me

[ScreaminSteve]

Thanks everyone for your help. We implemented the parameter change and have not had the problem since.

[Robodoc]

ScreaminSteve,

Can you tell me what parameter was changed?  I have some customers who have the same problem and I would like to pass a fix on to them if I can.

Robodoc