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Drawing straight lines with MPL800

  • MPL800 dx100 - using robodk software to create program

    So we have this robot that we want to use for laser cutting. Before getting there we a practicing drawing by mounting a pen on the robot arm.


    We do however have a problem which we cannot figure out how to solve for our MPL800 robot which is strange cause we got it working on the MH24 robot

    To test the accuracy of created JBI file we created a drawing of a rectangle and tried to draw it. JBAX2.txt It was way of both according to the dimensions and the lines were not straight. The pen is mounted on a tool with a offset so we corrected the TCP in robodk and on the robot we created a tool with the same dimension. After calibrating the tool and entering these dimension into the program we got a satisfying result. This was on the MH24 robot

    We then did the same on the MPL800 but this did not correct the issue. To test the calibration of the tool we manually created a program directly on the robot and was able to draw a perfect rectangle. As you can see the rectangle that came from the robodk is off.


    Does this problem ring a bell to anyone?

  • Have you controlled that the robot is mounted completely flat on the ground?
    Did you try to configure the drawing paper as a User frame and then create four p-variables with the same Z-value but with differing X- and Y-values:

    CornerPos1: X = x1, Y = y1

    CornerPos2: X = x1, Y = y2

    CornerPos3: X = x2, Y = y2

    CornerPos4: X = x2, Y = y1


    If the tcp deflects when moving on a set Z-value maybe the calibration is off?

  • Any time you take a program from the virtual world and put it in the real wold you must build a filter that adjusts the program for any changes in arm link lengths, robot position to the work....

    Robodoc

  • Any time you take a program from the virtual world and put it in the real wold you must build a filter that adjusts the program for any changes in arm link lengths, robot position to the work....

    Every information regarding robot dimensions has been entered into to software so it should take this into account. The dimensions has been taken from the robot specifications sheet so maybe I will go and measure it myself

    Edited 2 times, last by jba ().

  • Just checked the measurements and they were spot on

    How did you check them? I believe what Robodoc is talking about is into the micron level measurement of each individual axis. When the controller was initialized, the software loaded default parameters for the link length. Every MPL800 has the same data. Due to machining differences (tolerances) of the casting every MPL800 will be slightly different. The filter Robodoc is talking about applies the actual link lengths for that particular robot.

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  • How did you check them? I believe what Robodoc is talking about is into the micron level measurement of each individual axis. When the controller was initialized, the software loaded default parameters for the link length. Every MPL800 has the same data. Due to machining differences (tolerances) of the casting every MPL800 will be slightly different. The filter Robodoc is talking about applies the actual link lengths for that particular robot.

    The precision of my measurements were no where near micro level. It was just to check if the overall dimensions of the robot was correct (a guy from robodk suggested that maybe we did not have the excact robot that we thought we had)

    When we first got the robots we had guys from motoman to come and install and configure them.


    But lets says that some of these measurements a off. Could that lead to that big a diviation in the drawing of the rectangel?


    If I place the pen in the center of the robot and make a new program where I correct the position then it draws a perfect rectangle.

  • does you software create points in pulses or cartesian?

    It can do both but when using cartesian the JBI file cannot be loaded into the robot.


    The problem has however been resolved. There were several issues concerning how the robot was configured within the software. All these issues have now been taken care of by the software company

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