Autotune successfull on low kv Motors, heavier Quads, advice?

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- - Gerhard Laubscher > Emin Bu April 4, 2016 at 2:23am
    
    Hi Emin,
    
    Thank you for your comment.
    
    I will go through all the set-up/config processes, as from 'scratch' , I hope ;)
    
    Regards,
    
    Gerhard
Fnoop March 31, 2016 at 1:29am

Hi Gerhard, you 'should' be OK, but you would want to test the motors on the ground first. I fly a 650 sport as well but I use sunnysky 3508 580kv motors and hobbyking afro 20a eSCs and 1550 props, so you are quite a bit lower KV. I've never had any desyncs in flight except when using active braking (don't do it!). it's great that you can fly it successfully manually and I assume you haven't had any problems.

When I first build/try a quad I always take the props off and 'fly' it on the ground - first of course check the motors are all spinning the correct rotation and then I gun the throttle as fast as possible up and down and make sure they respond as expected. Some people advise then strapping the quad down (tightly!) and repeating this with the props on but I've never felt comfortable doing that. I then fly it in stabilize mode and when i'm happy it's reasonably stable in hover and gentle flight I then again gun the throttle up and down as quickly as I can many times as I can take, and also left and right and front and back as violently as possible. All of these actions replicate as well as possible manually what autotune will do - very quick bursts of throttle on certain motors. If these tests go well then at least you've done your best before invoking autotune, which has never gone wrong for me yet (touch wood!).

It's also very much worth looking at your ESC firmware. Assuming you've got hobby*w*ing ESCs I know nothing about those personally, but they have a superb reputation. Hobby*k*ing ESCs which I have less so :) SimonK firmware is known to be prone to desyncs because it focuses more on fast throttle response which is what incurs desyncs on lower KV motors, so I changed to blheli immediately, which has smoothed throttle, and never had a problem although my motors constantly screech which tells me I must be near a desync.

Upgrade to latest 3.3 and give it a go, I would definitely do it outside over grass as it's a softer landing if something goes wrong! The only desync I've ever had, when trying active braking, it nosedived hard into a tree and didn't damage anything at all except for a mast. If I'd been inside a hall I suspect there would have been heavy damage to it.

Good luck :)
- Gerhard Laubscher > Fnoop March 31, 2016 at 6:21am
  
  Hi Fnoop,
  
  Thank you for input and advice.
  
  I have indeed checked and verified the points you mentioned, prior to my initial test-flight attempt.
  
  And yes, I have flied successfully in stblz m, to date.... ;)
  
  as well as AltH,PosH, Loi, performed RTL and Land.
  
  I bought HobbyWing Xrotor, from what I understand their ESCs are pretty 'good'.
  
  If the ESC 'desync' condition is indicated by ESC 'screeching' sound, at this time, particularly
  
  from this morning's test result, I did not detect ESC desyncing.
  
  I made further comments on this main topic thread, points relating to what you mentioned here.
  
  Regards
  
  Gerhard
- This reply was deleted.
  - Gerhard Laubscher March 31, 2016 at 6:10am
    
    Hi Tony,
    
    If you are referring to my build, I am using 6S 8AH,
    
    which I believe is ample for my application. (See the intro)
    
    Regards,
    
    Gerhard
    - This reply was deleted.
      - Gerhard Laubscher March 31, 2016 at 6:52am
        
        Ahhh Tony,
        
        Thanks for pointing out my 'typo' spec mistake.....
        
        >> indeed HobbyWing...... of course :)
        
        I also use the Tarot brand 4114 320kv motors.
        
        The motors really sound great when they spin-up.
        
        I guess I can't edit the initial topic thread to refect the correct build info?
        
        I will add the correction in the main topic thread though.
        
        I am so glad to here there are more DIY'ers using the same frame and components
        
        which I am using :)))
        
        In hindsight, I think I should have opted for higher kv motors,
        
        I say this without motivation though.
        
        btw, which brand/model motors and Batts are you using?
        
        I am using the GensAce Tattu 6S 8AH
        
        What is your overview and experience with this frame/components and PixHawk?
        
        I am using the Taranis X9D+ radio at this time.
        
        Regards,
        
        Gerhard
        
        This reply was deleted.
        
        Gerhard Laubscher April 1, 2016 at 1:35pm
        
        Hi Tony,
        
        Thank you for sharing.
        
        Since you are flying a similar frame and comps, what are the typical vibration levels according to your log file? I had advise from George that the craft's vibration is way off. Looking at my last flight log it appears well above +-2 on both X&Y
        
        Is it possible that you can load and share a log file of your craft?
        
        Can you share any pointers re ensuring low vibes on your particular craft,
        
        besides what is mentioned on the wiki?
        
        One thing I didn't do was to balance the CF props (1550). For some reason I thought CF are balanced, more than plastic props. Apparently not so.
        
        So this weekend I intend to do -
        
        prop balancing
        
        Load FW 3.3.3 and re-calb craft
        
        Then hope to fly it and do further investigation re vibration levels.
        
        Regards,
        
        Gerhard
        
        This reply was deleted.
        
        Henny V April 4, 2016 at 4:58am
        
        Weather near perfect in Sunny Australia
        
        Henny V > Gerhard Laubscher April 2, 2016 at 2:16am
        
        Hi Gerhard
        
        To perform autotune you must have the following. In alt hold mode and the throttle at or very close to 50%. If the throttle is not 50% autotune wont start. I recommend you perform the 3 axis autotune one at a time. This is set in Mission planner. You will be surprised at the autotune perimeter results. My X8 flys great after autotune. Very Happy
        
        Cheers Henny
Gerhard Laubscher March 30, 2016 at 11:28pm

Hi All,

Thank you for your valuable input re ATun etc.

Steps I am going to take includes -

Upgrade to latest stable FW

After setting the default params and fly in stbz m

Fly in AltH to record frame vibes.

If this is within the params, I am going to attempt ATun.

I will keep you posted on my progress.

Once again, thank you DIY.

Regards,

Gerhard

Cape Town
Andre K. March 28, 2016 at 10:05am

what exactly are your concern, and what is it based on ? - untested sync issues in your motors/ESC's or the tuning loop itself ?

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Autotune successfull on low kv Motors, heavier Quads, advice?

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