3.2 on Pixhawk,poor altitude hold PLEASE help !

Due to taking my quad for a swim, I replaced my beloved APM with a Pixhawk.

I'm finding alt hold terrible, constantly drifting up and down. Also quad doesnt know when its landed (altitude wise)

A list of questions, before I downgrade back to APM(which worked solid, and has done for over 12 months.)

  1. The pixhawk didn't have foam on the barometer, so i installed it. made no difference. Shoud the pixhawk have foam on it?
  2. Does the pixhawk use GPS aswell as barometer to get accurate altitude. I was flying with poor GPS at the time. Also altitude hold wasnt working well indoors., with no GPS. But APM always worked solid indoors. So if i waited longer, would it of flown better ( when i was outside)
  3. Vibrations look ok.
  4. CTUN: Alt, Rel alt look odd? With barometer changing.
  5. Barometer reading is slowly ramping up when copter is not flying, is this normal? thermal related?
  6. Could this be just a mid point setting?

I've enclosed my logs. the Pixhawk is mounted on foam pads on a standard vibration mount with blue rubber shocks.

My previous APM was tuned perfectly, and in ALT hold would be like it was glued in the sky. Vibrations similar, slightly better.

I would really appreciate any help.

Thanks

Dave

2015-01-28 13-39-21.bin

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Replies

  • Moved back to APM, flies like a dream, out the box ! further updates to follow
  • I also was forced to go back to APM,
    Ok, I have PX4 but is was really sensitive and difficult in many ways (small connectors, firmware loading difficulties, PPM clitching etc), adding some lead to weigh it helped little bit (brutal, I know). I 3d printed frame with "earfoam" dampeners, vibrations little bit less.

    Maybe I give it (PX4) another try in the weekend after a year break, promised a lot of snow, so softer crashes ;-)

  • I will check te props, and get back
  • Thanks. Have you seen my log? I thought they looked really good? Although i get a imu mismatch!
    • yes, the vibrations were bigger than expected.

      And your problem description fits this kind of problem perfectly.

  • Fix your vibrations.
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