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Recommended PIDs for a large Quadcopter?

Posted by David Garcia on September 5, 2018 at 9:48pm

Hi all,

Ive just finished building a 1100mm 15 pound quadcopter with:

-24 inch props

-6215 kv170hv motors with 80A esc

-Pixhawk

-12s set up with 4x8A 6s batteries

Today I did the maiden flight and it lasted 15 seconds before it flipped and crashed.

I took off in loiter mode with 3D fix and the quad was shaking and wobling a lot before it flipped.

At first I thought Ive got 2 motors mixed up but I didnt, everything is set up correctly and props are spinning the right way.

Could wrong PIDs cause this woble and flip?

Im using the PIDs from a much smaller 750mm 15inch prop quad.

Please, I would appreciate it very much if someone could recommend the best PIDs for this rig.

Thanks,

David

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Replies

  • Andre K. September 10, 2018 at 10:59am

    Great, I highly recommend that you try autotune, configured correctly, it does a better job than most users can do, if nothing else, will put you on the right track to a good tune.

  • David Garcia September 9, 2018 at 7:07pm

    Hey Andre!

    So I flew again today and it flew beautifully!!

    I used the PIDs you suggested and also put the stabiliza pitch and roll on channel 6 in one of the dials in my Futaba with a 2 to 7 range...

    trid 4 first and it wobbled, then 2 and it went nuts and then I cranked the dial to the max 7 and it was amazingly stable.

    I will do a fine tunning this week and then try a to see how long it will fly for.

    Anyway thanks for your help!

    David

  • David Garcia September 6, 2018 at 7:11am

    https://youtu.be/cVIA1TQvark

    Andre, thanks so much for your reply.

    Please have a look at the video I uploaded in youtube from the crash.

    I took off in loiter mode, I tried switching to stabilize but was too late.

    Initially I thought Ive got a motor wrong or a plug up side down but everything was right which led me to think PIDs are the culprit.

    I will try again starting from your suggested numbers and let you know how it goes.

    Thanks again.

  • Andre K. September 6, 2018 at 12:39am

    you can't just copy PID's from one thing to another, as I hope you learned.

    nor can anybody here give you correct PID's except if they have exacty that setup, with same wight/balance/end ESC's.

    Assuming you calibrated ESC's , you should have lifted it up a bit in stabilize, barely off ground, and if wobbly, reduced pids.

    wild guess may be:

    rate pitch/roll P,I = 0.08
    rate pitch/roll D 0.004

This reply was deleted.

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