I'm currently having the issue where during our application of putting threaded inserts into holes in a box with a UR 5 if the force becomes too great for the robot it faults out and can't return to the previously programmed points. It gets close but is still off enough (~1mm) to throw off the insertion. Has anyone dealt with this or know of any way to fix it?

@C_Hoover one of the things that we have done to prevent the issue is to wrap the insertion inside of an if statement that is checking for the force to stay below a certain threshold.  We use the built-in force monitoring for most of the robots as it is sufficient to prevent faults.  We have one robot that actually uses the force to find the hole its trying to place the object in.  It will go up and down and "hunt" for the hole based on feedback from the force sensors.  If you do this you have to make sure to check the box on the if statement to check the conditions continuously.



Another thing that you can do is to place the node above inside of a force wizard and give the axes that are not being driven a little compliance, this can help the part find its own way if there is any lead-in on the leading edge.  We do this a lot as well as it makes for a much cleaner insertion of the part, tool, whatever into the mating feature.  The one thing I would say to remember is to lower the velocity and angle limits way down to start or you will find that the robot "flops" over.  

Not sure I have ever needed to measure the exact amount the robot is off after a fault to know if we have seen this issue or not.

Thank you, I'm relatively new to programing the UR but I'll have to play around with the force functionality of the robot. The robot, in its current configuration is really prone to "flopping" over, but that's another issue in its own. Do you know if the maximum force the robot is able to apply is velocity dependent or is the same at any velocity?

Since the standards call for limiting impact, I would presume that the force allowable varies with speed, being the faster you go, the less force you will be able to exert due to momentum.  One of the things that we do is we will move very fast until right before we need to do a precision process.  We will then slow way down and make that move.  There is also a function you can use to verify if the arm is actually at rest if you need to make sure that its not moving, is_steady().  We have used that when we want to move really quickly but then use a force function to make sure that the force function is not seeing residual bounce from the deceleration since we have a number of robots that not only are running at 80-90% of max speed they are also just about maxed out on acceleration values as the cycle time on several of them is very critical.

Also, make sure that any points that are critical do not have blends as that can throw off the actual placement of the robot in the point.  You need to have a waypoint with a stop here condition prior to anything that is critical in nature.

When you say the robot tends to "flop" over a lot what do you mean by that?

Thank you, by flop I meant that the current configuration that the robot is in requires a large number of joints to rotate in order to move in certain directions. Being that the robot tries to maintain a certain linear speed it can cause the wrist joints to quickly flip around or swing down to complete a move. The robot will soon be re-mounted in a more appropriate setup shortly however. Also I am not very familiar with the script commands the UR uses. Do you know of any literature or anything that would help me understand or at least show me a list of available commands and their function?