Round two on flying the quad successfully failed. On the first flight with just easy flying, the quad starts wobbling all over the place until I force it down quickly. Now on run two after a complete flash of the firmware and re setup. During an auto tune it did the same thing. But not actually during the tune as it was paused when I was re-positioning the quad. My guess is the stock pids are two high for the low kv of the motors. I'm not too knowledgeable on adjusting the pids with the Pixhawk but will certainly take some suggestions on where to set them to help it fly better and survive an auto tune. I'm fairly certain it's the stock pids because it is a little unstable just flying it around. I'ts like it can't respond fast enough with the low KV motors and large props. I linked a video of the last couple of minutes before the crash during the auto tune. 

Tarot 650 Ironman

Pixhawk with 3DR GPS

T-Motor 3508-29 380KV

15" 5.5 props

4S 5200

AUW 1590g

Crash vid - https://youtu.be/vA_LnW36m6A

Log file - https://www.dropbox.com/s/68fkzq0ik3o55ke/2016-04-12%2017-24-43.bin...

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what kind of ESC are you using ? Look like a ESC desynchronization when the UAV goes faster.

Anyway, we are using this kind of configuration and neither use the autotune. CH6 to fine tuned the P pid and around 0.14, the machine fly like a charm.

http://ardupilot.org/copter/docs/ac_rollpitchtuning.html

 

I'm using Afro 30A ESC's flashed with Blheli. I've tortured tested the ESC's and never ran into any sync issues. So I should drop the rates for pitch and roll slightly right? 

yes. Start en Stabilize, and when it look good, Alt Hold and Loiter.

We get once this sync problem, playing hard with the quad. But I guess theses machines are not good for race. Just auto mission at 10 m/s...

Ok one more question. The lower the value for example (0.0800) the slower the quad will respond right? Or is that backwards. 

yes. Start at 0.15 and I bet that you will not be below 0.14

I just have the same problem!! Crashed five times. When I use autotune the quad goes unstable.

Did you solve it???

Thanks in Advance

Tarot 650

Pixhawk with 3DR GPS

14" x4.7" Carbon Fibre props

6S 5000

Spider 30 Amp Opto ESC

Thats strange.. I used AT yesterday and it was just perfect. 

I fly a Tarot x4 with 40A Opto ESC SimonK

22x5,5 CF Props and 5008/ 330KV Motors on 6s

Put AT aggr to 0,06 and the gyro filter to 10hz

I read in the forums that it was an issue with low Kv motors and ESC with SimonK Software.

http://discuss.ardupilot.org/t/arducopter-3-2-1-autotune-problems-w...

Seems that my ESC can´t be re-program I use 30A Opto Oneshot 125 Spider ESC.

Here is a Link to my Log file

https://www.dropbox.com/s/rmyef6rgua48zng/2016-11-26%2018-40-21.bin...

Thanks

Niels G. said:

Thats strange.. I used AT yesterday and it was just perfect. 

I fly a Tarot x4 with 40A Opto ESC SimonK

22x5,5 CF Props and 5008/ 330KV Motors on 6s

Put AT aggr to 0,06 and the gyro filter to 10hz

And as I noted in that ardupilot thread, if you want good, worry free ESCs for low KV motors on heavier rigs, the Hobbywing Xrotors work great.  And no, I wasn't paid for that.  :)

As a matter of fact i was curious if my simon k would work with the low kv motors... I have 4 of the xrotor 40A in my stash at home ;) 

In my opinion that kind of setup in general requires higher PIDs, not lower... try to make an auto tune with reduced filter hz to 10 and try to play around with the auto tune aggression paramas

Tom Kopp,You should post your questions here http://discuss.ardupilot.org together with dataflash logs

POSTED LINK WITH YOUR LOGS DOES NOT WORK

This is new web where all developers "live"....no answers from them here

Maybe my post on tuning big multi with low KV can help

http://discuss.ardupilot.org/t/heavy-y6-adventure-thru-3-4-rc-with-...

Can you post your BLHeli settings?

One shot and oneshot 125 turned off?

Are you sure you calibrated ESC properly?

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