Autotune caused copter to fall out of the sky

[vyoufinder]

Autotune didn’t go well. I was pretty sure I was all set, after follwoing the directions as carefully as I could, and getting help from this thread: Mot_bat_volt_max & mot_bat_volt_min If you look at that post, you’ll see that I had an unanswered question, which may be related. Maybe I should’ve waited for an answer? Another thing I am thinking it could be is… When I flip my Autotune switch, at least when I am on the ground, QGroundControl does not show any flight mode change. Should it? Basically, as soon as I flipped my Autotune switch, the copter fell out of the sky, as seen in this video:

I’ve uploaded my flight log: https://drive.google.com/file/d/1KPISyWEJLRF-TI3mBXwKDnGRwLS5iUIu/view?usp=sharing

Anyone know why my copter just fell out of the sky as soon as I flipped my Autotune switch? Also, anyone know where I can get a replacement motor mount (shown in video.)

[mboland (Mike Boland)]

‘nough said.

Just wondering why you didn’t choose Loiter as the base flight mode?
I assign a switch to autotune seperate from my normal flight modes.
So when it is flying ok in Loiter I switch to Autotune and it will hold its position while it tunes (+/- 10m)

Also, have you been through the tuning wiki page and set your parameters accordingly?
The filter values are very important.

[vyoufinder]

Crap. Thanks for replying… Yep. I was going to set a motor stop switch on that stick, then changed my mind on which switch was which (because I am using a 6 channel remote with this one… and… didn’t write the params. … I think. Maybe I just forgot to change it though. Suck.

As far as why I did not initiate Autotune (or waht I thought was Autotune from Loiter Mode was:

@Leonardthall

Ideally you would do autotune from Alt Hold on a calm day. Starting it from Loiter or Pos Hold just makes it try to hold position gently and face in the correct direction through the tune. It does not make it softer or easier on the aircraft. It does mean the aircraft is relying on higher level controllers before you have ensured they are working correctly. It also will make the aircraft do strange movements that you may not understand or expect.

(You can trust what I say here about autotune because I wrote it, along with the attitude controllers, position controllers, and navigation controllers. I am giving you the best advice I can here.)

(and I do still trust Leonardthhall) - this was not related.

And, yes, I’ve thoroughly been through the tuning page, and asked plenty of questions on anything which wasn’t perfectly clear. I do still have one question, which hasn’t been answered at the bottom of this thread: Mot_bat_volt_max & mot_bat_volt_min - #24 by vyoufinder

So I’ve now set the switch to Autotune instead of Emergency Motor Stop… Now… Anyone know where I might find a new motor mount? Or maybe ideas on how to fix the broken one?

[skyveyor (David)]

Man, so sorry to see that, painful to watch. But the mountains are a beautiful background.

Not sure Mike’s response adequately explains what happened. Sadly I understand it all to well because I just did it. The log shows you never entered autotune, instead when you flipped the switch you commanded an emergency stop.

Sucks.

[vyoufinder]

Ya, my Emergency motor switch worked flawlessly didn’t it… Thanks on the background choice. I mostly chose it because there’s a lot of sand and a bit of foliage in case something like what happened… happened.

Now if I can just figure out a way to fix that broken motor mount…

[Leonardthall (Leonard Hall)]

Ahhh that sucks. Sorry to see that!

[vyoufinder]

Thanks for the condolences I’ve got it almost back together now. I think I can use some ever so slightly larger washers behind the motor mount, along with a heavy layer of super glue, and should be ready to tune again within a day or two, depending on the wind situation. I’ll recalibrate too since the pixhawk had to be re-mounted and moved ever so slightly.