Robot slow at one particular movement?

AriG

Hi everyone, very new user of RobotStudio here. I have been having some issues lately with my program. One move in particular in which the tool translates about 20mm and reorients by 45 degrees. This movement is done primarily in J5. In my program I have set the move speed very high, I have even tried up to max speed. In the RobotStudio simulation the move is shown as happening quite quickly but whenever I run the script on the actual robot (an IRB 4600) this move takes a very long time to complete. The flex pendant says that the program is running at 100% speed, and all of the other moves in the program seem to be being executed at more or less the correct speed. Is it possible there are some limiters set on the robot that are external to the RAPID program? If anyone has any other ideas they would be greatly appreciated. 

lemster68

The component of the speeddata which is limiting your speed is v_ori.  All of the predefined speeds, while they have higher v_tcp, have the same v_ori.  Make your own speed with a higher orientation speed.  Bigger zones might help if you can put some in.

AriG

lemster68 said:

The component of the speeddata which is limiting your speed is v_ori.  All of the predefined speeds, while they have higher v_tcp, have the same v_ori.  Make your own speed with a higher orientation speed.  Bigger zones might help if you can put some in.

I've looked into this but according to the manual all of the default speeds have a max orientation speed of 500 deg/s and the external axis speeds are maxed out at 1000 deg/s. My move is currently taking about 2 seconds to move 45 degrees so I kind of doubt that this is the problem. Especially since it seems to be working just fine in the simulation I feel like there is some safety setting or something on the robot that I have to change. Does this sound plausible?

lemster68

Do you have a high payload?  The robot will only move as fast as maximum permitted torque in any motor or gearbox.  It will not damage itself because someone tells it to go faster.

AriG

The tool weighs less than 1kg

lemster68

I don't expect that the cog will be far from the flange then.  So, back to your programmed speed.  20 mm @ 2000 mm/sec is .01 sec, 45 degrees @ 500 deg/sec is .09 sec.  None of which is close to the two seconds.  Anyway, are there fine points or timed movements?  A timed movement, regardless of a z50 or whatever, will be a fine point because it HAS to:  otherwise, how could it time it?  Try to play around with making your own speeds, with even slower tcp speeds but higher orientation speed.  It used to be, back in the day, that, with close points and high programmed speeds, the robot would run slower.  To get faster cycle times we would slow the robot down to get it to run faster.  Not kidding.

AriG

I am trying to rotate approximately 500g at a distance of about 200mm from the axis of rotation. I don't think it would require a large amount of torque. 

lemster68

You mentioned external axis speed earlier, is there an external axis involved here somewhere?

AriG

Hey sorry but we figured out the problem...the robot was in manual mode  . Sorry I'm still pretty new to this but thanks for all of your help. 

lemster68

  OK good!  So you were facing the 250mm/sec limit for manual mode.