YAW control not working, plus wildly spinning...

I am new to Pixhawk and PX4.  Been flying 'standard' off the shelf drones until making the dive in DIY.

I have the 3DR Pixhawk using stock firmware.  Its a Quadrotor.  I can get into specifics of parts and such, but not yet clear if that is relevant yet... I might be doing something dumb. 

I performed radio and pixhawk calibrations in Qgroundcontrol, all seems ok.  Initially I didn't tune the parameters, thinking stock values should be 'ok'.  So I have 3 problems, all having to do with YAW

1) I see YAW stick radio functions working when copter is hooked to qcgroundcontrol,  When I try to fly the copter, the YAW stick has zero effect on the heading.  I don't even hear the motors changing speed.  I cannot get this to function at all...

2) When it takes off, it will start spinning wildly on its own.  It tries to correct but way overshoots and just basically acts insane.

3) So ok, let me delve into YAW parameters... I tuned all the YAW Rate items to zero.  The copter now does NOT spin out of control, it just hovers.  It will drift of course with no correction.  I followed a bunch of tuning webpages (https://pixhawk.org/users/multirotor_pid_tuning), and as soon as I add a little bit of MC_YAWRATE_P, it starts to rotate around and around, sometimes trying to correct then wildly over correct, even with the smallest parameters.

I don't think out of the box it should be so difficult.  I am about to exchange the Pixhawk for another, thinking something might be wrong... but then again...

Any ideas what I can do?  I am new and learning, but I've been at this YAW for hours.  No reaction to stick inputs is a mystery, and the correction is out of control....

THANKS!!!!

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Replies

  • I think you have all the motors on backwards. IE Yaw counter clockwise actually goes clockwise which will confuse the flight controller but it will fly.

    I have recently installed PX4 flight stack and does work out of the box.

    • Ahhhhh HAHHHHH!

      I recently bought self tightening propellers, and they are opposite of my old propellers that needed caps.  I didn't even realize it.  Either that, or in all my rebuilding, I screwed up the CCW/CW engine placements...  

      When you said 'confusing' the controller, I realized that it made total sense.

      The ArduPilot SW now works out of the box.  I am going to load PX4 and see if it's the same, which it should.

      GREAT!  Thanks for all the tips guys, that was a NEWB mistake, but you were gently :)

      Derek

  • So I tried ArduCopter, and it does the same exact thing.  Starts spinning at takeoff in the same way.  I will try to tune it but first signs are the same behavior as PX4.  I suppose something is wrong with this Pixhawk unit.

  • So I now see Ardupilot and PX4 both can run on Pixhawk.  I think this particular website forum is dedicated to Ardupilot, or does it also support PX4? I am new, navigating what is what... 

    I may give Ardu Copter a try.  I'd like to get PX4 to work though now since it seems like it should... So am I in the right forum for PX4 issues?

    I will try Arducopter to also verify if my Pixhawk hardware is working.  Interesting!

  • So yes using PX4
    • I am not sure, how would it be reversed? It actually doesn't rotate any direction, seems totally ignored. Roll and Pitch work perfectly fine, as does the feedback.
    • 3D Robotics

      Possibly you've got your Yaw RC channel reversed?

      • You are right... see later reply...

  • I plan to move to Snapdragon, which I believe uses PX4... So trying to get familiar.
  • 3D Robotics

    Is there a reason you're using the PX4 firmware rather than the more common APM/Arducopter? The latter is a lot easier to set up.

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