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Mini hex + autotune = success.

Posted by Euan Ramsay on September 8, 2014 at 5:21am

Slapped together a factory-fresh mini hex with HK APM mini + 3DR ublox, balanced the props, fired it up in the air and ran autotune, in a breezy day. Over tuned with the factory settings, but flying ok now - just needs a tweak here and there.

This is the result. Needs  bit of D I think, to stablise it a bit. Maybe more aggressive control in pitch to stop the high frequency oscillations?

Will upload settings once I get home. 3.2rc7, factory fresh build.

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Comments

  • Euan Ramsay October 25, 2014 at 4:13am
    Re: "warbling" when giving it full power or "high g" turns - looks like the hz of the imu filtering does work!
    Been trying to tune mine out with PID and STAB_x, to some effect - but bumping the hz to 98 has had the most effect. It's still there, but is only audible now. No visible oscillating. I will use this 98 as the base for PID and tune from there.
  • DB September 12, 2014 at 8:59pm

    Saqib - you should be fine even without the vibe mount.  I've always flown hard mounted with no problem, unless blades are very unbalanced.  

    Euan - so switching to a 4s and 2 bladed props seemed to do the trick for flight time.  Now I'm using 5030s and flying with a Turnigy Nanotech 4s 1300 gave me 12-14 min of flight down to 3.6 V per cell under load. AUW is 517g including the Gopro and 140g of battery.  This is compared to 4-6 min of a similar Zippy 3s (without gopro).  I wonder if my Zippy batteries are just crap?

  • saqib shafiq September 11, 2014 at 5:01pm

    Its mounted on this jello platform using foam tape do you think it still might be affected by vibrations?

  • saqib shafiq September 11, 2014 at 4:59pm

    3701827791?profile=original

  • saqib shafiq September 11, 2014 at 4:49pm
    Im going to try take off in alt hold once i have fitted a sonar and get a chance to fly outside. Im thinking of using your pids to start off with for it to fly better than what it already does then fine tune it or auto tune once the alt hold works
  • saqib shafiq September 11, 2014 at 4:43pm
    No when im hovering slightly a feet off the ground and i change to alt hold the motors go back down to starting speed? The controller flies well in stabilise. I thought its some setting with the throttle mid point? I havnt switched alt hold in mid air just incase it drops. It might be because i wasnt giving it enough throttle for it to stay in one place.
  • Mark Steyn September 11, 2014 at 4:16pm

    What is is doing when you engage alt_hold? shooting up in the air a few metres? 

    Usually that is a sign of vibration issues especially on the smaller size frames.  I would enable the IMU logging and check vibration levels are within range. Easy instructions on the wiki. 

    http://copter.ardupilot.com/wiki/common-diagnosing-problems-using-l...

    hope that helps. 

  • saqib shafiq September 11, 2014 at 12:06pm
    Looks very good thumbs up. Iv got a hex from HK. 330mm emax 1806 2300kv with 12a simon k esc. Iv got the apm full version which is a clone. It flies well in stabilise but not getting it to fly in alt hold. Do you think your pids will work with mine? Thanks
  • DB September 10, 2014 at 9:25pm

    Yeah I was looking at those.. I may have underestimated my payload before I ordered ha.  The 1704s are half the weight of those, so your baby beasts better outperform the 1704s.  What kind of flutter/warbling are you getting?  Any videos of that?

  • Euan Ramsay September 10, 2014 at 12:16am

    Hmm - the 2150 "baby beast" multistars I have are running very well - on 3S, with a 900g weight and 5030 props they barely get warm, even in 25'c and after multiple packs. The 1704's are an older design, I believe.

    Interestingly, I'm still getting some "flutter" on Pitch at higher speeds. I need to try and tune P and D, I think.

    I also get "warbling" from the motors in a full power climb.

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