Problems with robot/conveyor syncronization

    Hello:

    We are using a F-series Robot with a RS-007 controller and to make the syncronization, we are using a+the specific module for that.

    Basically, we have interconected a PC with the camera software, a Siemens PLC (that basically makes the user interface and communnication) and the robot.

    When we take a photo with the camera system, we have the coordinates of an object saved,, then the plc sends a move order to the robot with that coordinates. The camera and the robot are separated 2440 mm and we use a CWAIT to measure the distance untill the object has arrived to the 0.0 axis of the robot and basically we simulate the axis of the photo taken with the axis of the robot, moving to the previously saved coordinates.

    The PLC send all the important values to the robot

    The problem is that, after some tests, the robot moves to the coordinate Y correctly but the coordinate X seems to variate randomly, for us, the robot is having some problems following the conveyor belt. We have tested the encoder and the camera system and they work alright, so, maybe the code we are using to syncronize with the belt is not correct.

    Maybe some of you that have more experience in this matter can shine some light to this "problem"

    Thanks in advance

    Quote from PauChiquillo

    The problem is that, after some tests, the robot moves to the coordinate Y correctly but the coordinate X seems to variate randomly,

    What exactly does this mean, you really need to be more specific when you talk about random as to what is actually random?
    - Random as in values received.
    - Random as in positive or negative values.
    - Random as in what sort of range differences - are we talking 1mm, 10mm, 100mm etc.

    If coordinate value in camera is exactly the same as what is received at robot side, then some other factors could have an effect on physical positions, such as:
    - Physical EOAT, Robot or Conveyor not suitably mounted and secured.
    - Speed checking, is there better results during slower speeds or no difference.
    - Encoder resolutions and settings, are these used directly at robot side and set accurately.
    - TCP values accurate with physical EOAT mounted.
    - Physical EOAT mounting must be same as TCP values used.
    - Physical alignment of robot to conveyor must be accurate or drift can occur over long distance.
    - If part on conveyor changes position on belt after camera during travel.
    - If conveyor belt itself is not parallel all the time during conveyor motion.
    - If conveyor belt and encoder are coupled without missing pulses during motion - belt slipping.

    I notice you have 175 value for A element, why is this?
    - Can you provide image of layout of robot position relative to conveyor.

    Quick question on your setup. Is the variability more noticeable the further away from the center of the conveyor? If yes you may need to look for a different camera or lens for the camera. The image may be distorting and throwing off the position details.

    Also I presume the axis you have reliable locating is the center line of the conveyor. More specifics will help dial in solutions for you.

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