what will happen in emergency landing when fail throttle set to 1000 with airmode enabled?

[lida2003]

I have a few questions about airmode feature.

a)How airmode works?

b)does emergency landing get airmode feature?

c)so what will happen in emergency landonh when fail throttle set to 1000 with airmode enabled?

ps: failsafe throttle 1000/hover throttle 1500, default settings.

[Jetrell]

We touched on this, on Discord last week.

A) For multicopters, Airmode is designed to keep the PID loop active and allow attitude stabilization when the throttle is lowered, in freestyle flight maneuvers.. To accomplish this, it basically only requires the integral part of the PID loop.

B) Only if its permanently enabled or enabled with FS in the modes tab.

C) Air mode will try to maintain the quads present attitude as its descending.
But in your case (a tumble) it will not succeeded, because the integral term by its function, can not respond fast enough to the error. It would require the P-term to act first, to halt the spin.

Hover throttle is only applied when there is trusted sensor data.

[lida2003]

Now, it's close to what the scenario I wanna talk about.

There are two options here for emergency landing:
a) hover_throttle when >=EST_USABLE
b) failsafe_throttle when <EST_USABLE

And worst case is failsafe_throttle, if we have this case activated failsafe_throttle = 1000, is air mode able to maintain present attitude?

If we can't maintain present attitude, what't difference between emergency lading and FAILSAFE_PROCEDURE_DROP_IT?

PS: that's what I have mentioned in tumble (prop stall???) when emergency lading.

[breadoven]

Emergency Landing doesn't disarm ... FAILSAFE DROP_IT does disarm immediately IF Failsafe is active .

At worst an Emergency Landing without Failsafe active will use Idle Throttle if Failsafe is set to DROP. This is essentially a drop but with attitude control, at least so long as airmode is working. What is your setting for airmode_type ? Also I don't suppose you can remember where the throttle stick was when the Emergency Landing started by any chance, i.e was it at minimum ?

[lida2003]

At worst an Emergency Landing without Failsafe active will use Idle Throttle if Failsafe is set to DROP. This is essentially a drop but with attitude control, at least so long as airmode is working. What is your setting for airmode_type ?

set airmode_type = THROTTLE_THRESHOLD, maybe the backup dump file will give much more details.
INAV_6.1.1_cli_20230627_122419_dump.txt

Also I don't suppose you can remember where the throttle stick was when the Emergency Landing started by any chance, i.e was it at minimum ?

Emergency landing happened when RTL. I haven't touch the throttle stick until the last moment, And I think it's around ~46%.

[breadoven]

OK ... in that case it's not clear why the quad tumbled given airmode should have been active and maintained attitude control even at 0 throttle.

[lida2003]

Yeah, it seems like a puzzle without the log.

BTW, The sound of props, when RTL swithed to emergency landing, it sounded like propeller stall. So I think maybe as @Jetrell said failsafe_throttle = 1150 for conservative default land settings.

If this physical phenomenon (propeller stall at failsafe_throttle = 1000) is possible, then the default parameters failsafe_throttle need to be adjusted.

[lida2003]

Just add a link to Emergency landing tumbled crash? -- inav 6.1.1 #9184