RobotStudio event

External axis control

leonardolt
leonardolt ✭
in Robot Controller
Hi all.

I have an external axis that is just a single motor. This motor was mounted on a rail that is suposed to position the working object. The fact is that the rail is not moving linearly neither stopping in a solid position. While moving the positioner bounces, except if extremely low speed is used (less than V5). When is is suupposed to stop, it oscilates around target position.

This is quite a powerfull motor, at about 4000W. It should have no problems driving this ultralight aluminum profile rail with ball bearings path. The motor shaft is attached directly to the pinion that drives the rack. As the positioner can move fast enough in high speed and has acceptable precision in low speed, it seems it's not missing a gear box.
For me it seems that it is a matter of  tunning control parameter ( Kp, Ki, Kd, for example).

I let here a video of the process, so it may be easier to understand.

[TUBE]z-TI0nN8Mlo[/TUBE]

Comments

  • Marcel
    Marcel ✭✭
    Hi
     

    You have to adjust the MOC.cfg file.

    Do you have the correct motor definition under: MOTOR_TYPE?

    Did you try to modify in the LCM0 section: Kp, Kv, Ti values?

     

    Best regards

    Marcel
  • leonardolt
    leonardolt ✭
    Hi Marcel!
    Thanks for the tips! I did not know what was LCM0 about, but now it seems that it may be a solution for my problem. I colud not test it yet because an unexpected error prevents me from executing any program... Well, but that's for another post.

    As soon as Ican I'll try changing these parameters and than I report here the results
    Thanks again

    Leo

  • leonardolt
    leonardolt ✭
    Dear Marcel,



    Your advice about LCM0 Kp, Kv and Ti was exactly what I needed. I just
    tunned theese parametes and, that's over. Everything is moving smooth
    now. And, by the way, I had already configured the MOTOR_TYPE group, so
    all the parameters were ok.



    An ABB doc (3HAC17076-1_REVH_EN - IRC5 Technical reference manual)
    helped me on tunning LCM0 Kp, Ki and Ti. This doc explains all the
    parameters in the configuration file.
    The 1MB file size limitation avoids me uploading it here. But i seems that a simple google search and a couple of clicks can solve this.




    Thank you  again



    Leo

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