My first official foray into 3.1 has not gone well, and so far, Gravity - and his mistress, the hard frozen ground - are winning 2:Nil.
Both bird were flying fine on 3.0.1. There have been no physical changes. The Disco even flew ok on 3.1, pre-autotune, although I still can't seem to find the source of the vibes.
The Disco started autotune no problem, and you could physically see roll getting tighter and tighter. Pitched started, and that looked good too. I was getting excited. Right up the moment it totally flipped out of control, Belly bounced off the tarmac, and proceeded to freak out some more and self-destructing. Logs are attached, and apart from less than satisfactory vibes, no idea why it freaked out. All physical connections were tight even after the crash, and there were no loose screws or bolts. The new 3.1 engine readings look weird btw...something in there, maybe?2014-01-12%2008-25.log2014-01-12%2008-25.log.gpx
So I moved onto the quad, which was even more bizzare. It tried to do a fly away the moment I flicked autotune. So I flicked out, but it now went into failsafe RTL. Broke RTL into loiter, and it freaked out again. Realising this was not a route to safe flight, I went back to stabilise, and discovered I had lost all yaw control. Then I made a mistake - instead of just putting it straight down in stablise, I flicked manual RTL, and boom - all motors stop. Stabilise again, but I was too late. Wish I had the logs for that one, but I think the logs are corrupted - it fails at the same point very shortly after starting the download. As mentioned - It was running sweet in 3.0.1...Compassmot: 0%, Vibes well within +/-5, etc. Only thing changed was the upgrade to 3.1.
2 freakouts in Autotuine on 2 aircraft in the same morning session. Both were flying well previously. Methinks I'll stick to the manual PID method, until my confidence is restored...
Amazingly, both are now phyisically repaired already. Disco ready to fly, and I'm doing a ground up, factory-fresh install on the Quad. The fog has come though, so visibility down to 20m. I had a lot of flight activity planned, but it ended up being a frustrating - and short - weekend's flying :-(
Comments
If anyone can see what the Disco did wrong, I'd be most grateful. Apart from the APM, it's a bog standard disco, running recommended motors, ESCs, props etc. CoG is within a milimetre of recommended. Flight weight is right in the ballpark. There are/were not mechanical issue with it - in fact all 4 motors and 4 arms are brand new, and props have been triple checked for balance (in my quest to find the vibes). It's powered by a 3DR PM on a 4S. Vibes - while high - are normally borderline +/-5.
In short - there was absolutely no reason for AT to fail.
Something came to my mind: Maybe the more sophisticated/expensive/heavy the physical setup of the copter is, the more basic and bulletproof the flightcontrol should be? Just an idea.
Hi Bill,
Yes, I've followed the Autotune forum, but it doesn't explain why both my rigs failed. I know it's an optional feature, but surely an optional feature should still not crash the vehicle? What's next - "Please use at your own risk!" messages?
I chose to run AT with the gimbal on board, but that wasn't the cause - the problems started immediately I went into AT; the gimbal problems start once the twitching starts. THe frame is a quad frame heavy with 21.5mm CF arms - more than stiff enough, so wasn't that.
I've actually spent the entire afternoon dismantling the quad to try and identify what caused it's bizzare behaviour. And I think I've found it - purely by accident.
While testing the voltages across the APM, I noticed a strange thing - my braincube LED"s would occasionally flicker. Since it only powered up or down based on a rx input, I thought "Lets have a look...if the rx is getting glitchy, that would be consistent with the bizzare behaviour". And look what I found!
Exhibit A: Satellite connects loose on one side, and bare wire visible on the other. By playing with these I could effect the flicker of the braincubes!
Now glitching satelite connections shouldn't cause such bizzare behaviour, but then I found this...one of the rx antenna's had been vibrated loose, and was scratching itself across the rx circuit board!
So I slapped in a AR8000, and the LED's are rock solid. All other checks on the system checked out, so this must have been the cause. Leaving the 2nd satelite connector loose for the moment, as I'll be upgrading to a DX18 and 9ch rx in the summer so will be back on 2 sats again soon.
However...none of this explains the Disco problems...I went over it with a fine toothcomb, and found nothing wrong with it, other than the pre-existing vibe levels.
Quazi: Terence is fine! He's still on 3.0.1, flying well and autotune free..;) He's getting a new Grouse House Nex5 gimbal soon to help fix his CoG. Depending on whether I can afford it, he might even get an upgrade to U series motors and 17" props, for a 30 minute hover.
Read AC-3.1 autotune support discussion reply by leonardthall on November 19, 2013 at 7:14am
It might be temperature issue - I suppose it was cold, if you brig your copters from warm place (home or car) and almost limitedly started temperature drift of IMU may change at unmanageable rate, and crash the copter. Also some ESC (cristalless) may incorrectly read PWM signal in extreme temperatures. You have telemetry radio on one photo - telemetry log contains temperature reading - could you provide it?
@Luis I think, you should autotune with gimbal, bat lock it with some zip tights, or so
but doesn't having the gimbal there with the weight affect the tune?
Hate to see your quads crashed.
I read something about removing all the wobbly stuff from the frame, like gimbals, when auto tuning. Might give that a try.
How is Terrence?
i moved from the dji 30 optos to the affro ones, updated to the latest simonk fw
Are you running SimonK on the ESC's?
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