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I could use some help with my skywalker, using pixhawk.

Posted by NIK.YAP on August 5, 2014 at 9:59am

Hello,

I did a maiden today. trimmed out in manual mode and then i went into stabilize mode. Flew very well actually. nice and stable and plane centers back when let go of sticks.

When I tried FBWA, I could not get the plan to roll left or right. It just wanted to keep going straight. I think ONCE when I hit the stick full right, i saw the plane banking right a little bit.

How do I fix this issue with FWBA?

I also wanted to find out the main differences between STAB and FWBA. Do they fly the same way ? I read the documentation, but maybe i'm misunderstanding.

Thanks!

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Replies

  • NIK.YAP August 17, 2014 at 5:34pm

    Ok,

    So I set my P values to 2 and the plane started to react to my rolls.

    So far as I can see, FWBA is the same as STABILIZE mode? Only that the banking is limited to whatever the angle limit is , is that correct? 

  • iskess August 6, 2014 at 12:46am
    My typical P values are 1.6 to 2.1 for Pitch and Roll. It depends on whether I'm flying the 1880 or 1900 wing, and how I have the linkages set up. I have several Skywalkers. You could try 1.5 which should be good enough to start autotune. Don't ever just use someone else's PIDs, they just provide a reference point.
    Check out the Aero stock PIDS, they are very high as well. The Skywalker needs huge control surface throws to maneuver well.
  • iskess August 5, 2014 at 10:57am
    Yes, your Roll P is too low. Should be around 2 for a skywalker.
    • Georgie xu > iskess August 5, 2014 at 8:35pm

      Really ,2?  I start getting overshoot after 1.1. Maybe my servo throws are crazy:)  I fly too much 3D 

    • NIK.YAP > iskess August 5, 2014 at 1:12pm

      Should pitch P, be around 2 as well ?

    • NIK.YAP > iskess August 5, 2014 at 1:12pm

      Thanks. Will increase the P.

  • Tom Mahood August 5, 2014 at 10:24am

    Did you do a radio calibration? In Manual mode the RC controls are just passed straight through, and in Stabilize it only does self-leveling. The FBW modes take your stick inputs and react to them. If it isn't seeing correct stick inputs, then it won't do much.

    You can test either FBWA or FBWB on the ground. Ailerons, elevator and rudder should respond as usual to your stick inputs. In addition your control surfaces should respond to counter your movements as you pitch or roll the plane by hand.

    • NIK.YAP > Tom Mahood August 5, 2014 at 10:29am

      Hey,

      Thanks for the response.

      Yes FBWA works on the ground, it follows the stick movements correctly. and counter moves when I hold the plane in my hand and roll left , right or up and down.

      Would increasing P values for roll , pitch help ? I lowered the P values. I'm using the 3dr aero param file, with the exception of the lowered P values that I reduced.

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