FANUC robot repeatability issue for Handling Application

    Hi,

    I am facing issue with Fanuc M10iA ID/16S manipulator and R30iB Plus controller. Its used for handling application (Pick and Place). The payload of the tool is 1 kg and product weight is around 150gms. The robot picks part from Point A & drops at Point B or Point C. There is no issue while picking part from Point A but while placing randomly sometimes the robot shifts its place position in X and Y both directions. The offset is sometime +ve & sometimes -ve and this offset is random. Out of 6-7 cycles, we get this repeatability error, collides with fixtures and stops with collision error.

    Kindly assist me in resolving the error. I also noticed new parameter as shown in the image highlighted with yellow. Please help me with understanding DB 20.00mm & 10.00mm parameter also.

  • Go to Best Answer
    Quote from Nation

    DB means distance before. On your first point, it is saying to call VAC_OFF 20mm before you arrive.

    Also, indirectly addressed PRs? ew.

    What is the magnitude of your repeatability error? I am not aware of this ve nomenclature.

    Yes, the place has 2 positions which is decided by the PLC. If position 1 is selected then PR[R(32)] has a value stored in PR[10] & if position 2 is selected the PR[25]. These 2 PR has fixed location.

    +ve & -ve, I mean to say positive & negative offset. The repeatability error varies from 10 - 35 mm.

    Quote from Fabian Munoz

    When you say "placing randomly" , Is the robot getting coord from a PLC ? Could it be possible that the values of the PR are changinf while the robot is moving from A to any one of the other two points

    When is the value of R[32] update ?

    Yes, the place has 2 positions which is decided by the PLC. If position 1 is selected then PR[R(32)] has a value stored in PR[10] & if position 2 is selected the PR[25]. These 2 PR has fixed location. depending on location 1 or 2 received from PLC it chooses PR[10] or PR[25] which has fixed coordinates.

    Quote from Fabian Munoz

    Could you post the program before line 75 ?

    Is it possible that the PLC sends you a 1 and right after a 2 or even both at the same time ?

    Have you tried the program always using the same option from the PLC ? Somehow block place 2 on the PLC and work only with place 1

    Hey, yes definitely find the attached LS file of the whole program.

    Yes monitored for PLC sending place position and its sending 1 & 2 respectively every time.

    No haven't tried with only 1 position.

    But yes, I had sent image backup and All of above backup to FANUC and they sent an updated image file.

    Loaded that and restored the All of above and took trials. Its didn't crash or loose its oath now for around 30-40 cycles that we did today.

    Thanks for that, and its very important.

    Yes, definitely there was loosening of bolts of pedestal where robot was mounted. Secured them back with torque tool but still that issue persisted.

    After tightening the deviation was reduced however, we still had that random deviation in positive x or y direction or negative x & y direction.

    No reducing the speed didn't change the scale of deviation or changed the distance of shifting.

    But yes, I had sent image backup and All of above backup to FANUC and they sent an updated image file.

    Loaded that and restored the All of above and took trials. Its didn't crash or loose its path now for around 30-40 cycles that we did today.

    • Best Answer

    Regular usage and exacerbated with collisions can result in 'loosening of bolts, fixtures' and is always top of my list before diving into code.

    By reducing the speed of the robot, if this was the case could result in the total displacement changing also.

    But, it appears not to be the case in this instance.

    Seems a little 'sledgehammer to crack a nut' in order to rectify it, as there doesn't seem to be an answer to the problem.....

    What have Fanuc actually done, have they explained - ie version upgrade, software revision etc

    Quote from kwakisaki

    Regular usage and exacerbated with collisions can result in 'loosening of bolts, fixtures' and is always top of my list before diving into code.

    By reducing the speed of the robot, if this was the case could result in the total displacement changing also.

    But, it appears not to be the case in this instance.

    Seems a little 'sledgehammer to crack a nut' in order to rectify it, as there doesn't seem to be an answer to the problem.....

    What have Fanuc actually done, have they explained - ie version upgrade, software revision etc

    Yes your are right!!!!

    No updates from FANUC what exactly did they do with the Image backup. But yes some software package they mentioned about which they installed.

    Now i yet dont have exactly what software package have they installed or any particular updates. But yes they said they tried running it on a robot at their warehouse, tested and then sent back for us to test here. Today whole day we didn't had any crash or deviation.

    But yes, tomorrow we would be trying full fledge continuous run of the machine and robot just to make sure that issue has been resolved. Once confirmed will update what exactly did they have done in the Image backup.

    Thanks for you valuable inputs.

    Hmmm.....wonder whether there is 'bug' then in the DB processing perhaps with the current version you're running.

    That's the only thing that comes to mind, as your code is relatively standard code.

    Would be good to know the definitive change they made as if it is a bug, no doubt someone else is likely to encounter something similar and this thread could certainly help save time if the resolution is a software upgrade.

    Wonder whether this could show it's face in Roboguide......maybe worth getting before/after data and bashing them into Roboguide and seeing if it shows up if you have that capability.

    May also be worthwhile reviewing your accuracy settings too with your CNT value from R[42]

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