Have a Fanuc 2000iB / RJ3-iB controller giving us a noodle scratcher over the last few days..once, sometimes twice a day, the robot ( with an end of arm tool for picking parts out of an injection mold ), will over travel by about an inch and give a collision detect fault, as the tool is not lined up with the parts when it tries to go to that pick point..
When we go back a few steps and run the program with T/P, the robot goes to the correct taught point and picks the parts..on restart, there seems to be no apparent problem..
Joint disturbance torques and current draws are well within allowable limits..
At the point where the overtravel occurs, J2 and J3 are past the taught point angles, as is J1..the minor axiis are spot on exactly where they should be..
When this problem showed up, air moves into the press were at 2000mm/sec, right up to the approach point and then 250mm/sec to go to pick..these speeds had been such for several years..when this problem first showed up, slowed down the last air move to 1500mm/sec and later that day, the overtravel happened again..yesterday, after another occurrence, slowed down to 1200mm/sec and now this morning after the most recent occurrence, slowed down to 1000mm/sec..hasn't happened for the last 4 hours, but I need to figure out why this is happening..
Incidentally, J1 @ home is 40.272, at pick it is 67.015 and at the overtravel is 67.523....J2 @ home is -47.555, at pick it is 59.854 and at the overtravel it is 59.896...J3 @ home is -11.040, at pick it is 4.492 and at overtravel it is 4.454
I also find it a bit unusual, because I would expect to see a stop excess error with something like this...
We're putting a call in to Fanuc...it is the weekend and the robot is still running...don't know yet what decision will be made about service, at this time..
Any input or insight will be greatly appreciated !!
Cheers !