iNav tilting at full throttle on latest firmware

LitterBug

Troll Spammer
There were a couple really odd behaviours in the inital setup of Betaflight that never happened with iNav, the worst being some sort of windup in ANGLE where a resonance developed and then the quad decided to start climbing even after chopping throttle to zero.

I had this happen several times with betaflight back when they introduced airmode. There is a serious flaw in airmode that can cause it to "fly away" under the perfect storm of conditions. Almost lost a lot of skin one time (got lucky with scratches), and had to drop from 80' after arming with another.

Every firmware seems to have it's strengths and weaknesses....
 

evranch

Well-known member
Well, enabling "Absolute Control" resulted in flyaway in both ANGLE *and* ACRO/Airmode and 2 drops from about 20'... And the loss of my last remaining VTX antenna. Not impressed as it flew stably for about a minute before the flyaway began, so it really feels untrustworthy.

Glad I'm using cheap pagodas. No quad flying for a week or two until Amazon gets me some more.

Maybe I'll copy these PID settings back to iNav and see if they are successful in keeping it from rolling over. Or maybe I'll try ArduCopter since it runs on F4 boards now...
 

evranch

Well-known member
Helicopters, of course! Sometimes I forget that they are still a thing with multirotors dominating the market.

I think I'll give it a try, something to do while I wait for antennas. I found an old 5.8 dipole from my goggles and stuck it on to avoid burning out the VTX but it's extremely flimsy. I've trusted Ardupilot with fixed wing for years, it's a very mature system. And it has all the features I need and then some, RTH/Position hold/Camera trigger which could be used for the sheep beeper.

Right now iNav/Betaflight's beeper triggers are tied in to the main system which results in occasional deafening beeping on errors. Would be nice to have the 140dB beeper on its own dedicated channel.

Gives me a chance to learn about it too, since I've considered doing a multirotor aerial photography system and Ardupilot is the obvious choice for this. I like my fixed wings, but sometimes if you just want a couple shots of a jobsite sending up a huge wing is not the practical option.
 

LitterBug

Troll Spammer
I started out 5 years ago on Ardupilot. Having to re-learn a few things and first learn others. I was really stoked when the chibios version came out suporting alternate FCs. I have a PX4 setup that will go on my x650 quad if I ever get around to finishing that build. Should be able to lift over 15 lbs, not that I'm ever going to put that much on it. But could use all sorts of cameras and RF scanners.

They FINALLY have the ability to switch arm in these newer releases. That whole hold the sticks arm/disarm seemed to me like an accident waiting to happen.
 

evranch

Well-known member
They FINALLY have the ability to switch arm in these newer releases.

What! I didn't notice that. I'm changing that today on fixed wing, hey I might take my new wing up and try to finish tuning it so I can get a camera mounted. Spring runoff is the best time to map for drainage and it's melting fast.

Not such a big deal holding the rudder on a fixed wing, but it's still kind of stupid. I've always disabled stick disarming for fear of killing my plane while making a left turn. So once I'm flying there is no way to disarm.

The holding delay is bad too since if you need to disarm, you usually need to do it right now. Switch is much better.
 

evranch

Well-known member
OK, so ArduCopter doesn't really support my board. It flashes and connects but that's about all it does. Crashes when trying to calibrate, even.

Back to iNav to try to get a solid tune. Too bad I had to lose bidirectional DSHOT, maybe in a later revision.

Boosted the I gains through the roof to match my Betaflight results. Indoor hover in AIR is rock solid. ANGLE is still wobbly, have to figure that out with its own parameters.

Interesting the huge difference between Betaflight and iNav in ANGLE. iNav can build up a nasty resonance at 5Hz with probably 10 degrees of rock, but still maintain normal throttle control. If Betaflight started rocking like that, something would wind up and send it skywards.

I noticed one setting in iNav where you can choose the way Airmode works. iNav uses a mode "stick_center" where the I term is not allowed to grow if the sticks are centered, using a function called anti_windup. Or, you can choose the Betaflight default which is enabled after takeoff and never triggers anti_windup. Hmm...
 

evranch

Well-known member
Back out in the wind with iNav. And back to rolling right on punchouts even though I did find and enable an anti-gravity mode in the configurator. A fair bit of shimmy in the wind as well in both AIR and ANGLE, but it's not really fair to judge as it's really blowing out there.

Feels really stiff with all that I term and I think I'll bring it down where it was. Obviously it doesn't help with the roll over issue. Baffling.
I feel like the scaling of the PIDs on Betaflight and iNav is different since it was a great flyer with those PIDs when it did fly with Betaflight.
 

LitterBug

Troll Spammer
Too bad your board doesn't work with ArduPilot. Would be interesting to see yet another firmware run on the same platform for comparison.

Cheers!
LB
 

evranch

Well-known member
That was the main reason I wanted to see it fly, iNav and Betaflight are two sides of the same coin and ArduPilot is something totally different.

Time to try out the black box logger in iNav for the first time ever, I think. I want to see what is actually going on here. I still suspect all 4 ESCs are receiving a 100% command, resulting in inability to control attitude.
 

evranch

Well-known member
Should have tried out the logger before! Great feature that answers all the questions. Here's a punchout.
roll control.png


Motor #1, which is the sick one, is pinned but can't put out. It feels like right roll, but it's actually right roll and rear pitch. If I drag the time cursor, I can see the quad icon roll over as the red motor falls behind.

So... why not in Betaflight? I'd say this is a bit of a bug in iNav, actually. With motor 1 at 100% and that corner dropping, it should be backing off on the other motors. Instead, it holds them steady and assumes motor 1 will catch up, continuing the roll until I cut throttle.

Time to swap out motor 1.
 

ElectriSean

Eternal Student
Mentor
That is odd behavior from iNav, but I'm guessing their demographic doesn't do too many full throttle punch outs ;) It would be amazing to have all the functionality of iNav and fly as well as BF, but there are only so many coders out there. Glad you got it figured out :)
 

evranch

Well-known member
I feel like I'm definitely pushing the limits of what iNav is supposed to be used for! I either cruise or fly aggressively, nowhere in between. However after the flyaway incidents I really feel like Betaflight is made for 5" max race quads and not for larger machines. Maybe with smaller props and less inertia the potential for windup is not as bad?

I think I'll send this in as a bug report, while a lot of iNav pilots are not looking for racing performance I can see this causing dangerous issues if a motor is going bad. The last thing you would want is your expensive cinematic or mapping camera setup rolling into the ground because one motor can't put out at full RPM. Better to slowly settle to the ground with inadequate thrust, IMO.
 

LitterBug

Troll Spammer
I still have iNav on two wings, but am considering other options for them after the lockup I had. There was a time when I would have pumped time into iNav, but now that there are more, cheaper, and smaller options to run ArduPilot, that is my path forward, at least for wings and for multirotors that I want to use navigation with.
 

nevenelestate

No Agenda FPV
@evranch , have you tried reaching out to Pawel, either through his patreon where he will always respond to patrons, or on his YT Live Streams where he answers questions? He has been doing a lot of work with 7" and trying to get good ACRO performance too.
https://www.youtube.com/user/dzikuvx
I would also try posting in the RCGroups Cleanflight/iNav thread for a broader iNav audience.

@LitterBug what do you mean by lockup?
 

LitterBug

Troll Spammer

[USER=22963]@LitterBug
what do you mean by lockup?
Long story short, The elevon wing was flying fine till I tried to do an autotune. Switched to autotune, rolled right, and the control surfaces all locked up. No pitch control, no roll control. I could vary the motor speed, change out of autotune mode, but it would not select manual mode to get back to a safe state. Slow death roll from about 300' into the ground, fence, and tree. Barely missed hitting parked cars behind flight line. Knocked nose clean off.
 

nevenelestate

No Agenda FPV
Long story short, The elevon wing was flying fine till I tried to do an autotune. Switched to autotune, rolled right, and the control surfaces all locked up. No pitch control, no roll control. I could vary the motor speed, change out of autotune mode, but it would not select manual mode to get back to a safe state. Slow death roll from about 300' into the ground, fence, and tree. Barely missed hitting parked cars behind flight line. Knocked nose clean off.
That's an interesting one, I've never heard of that happening. I've had what sounds similar with my AR wing but it was because I entered a stall and the surfaces weren't setup properly, my fault, and smashed nose in from about 200ft. I've got iNav on several wings and have even put it into a Mini Guinea with no problems, but I haven't gotten around to setting up a quad to try iNav on it yet.