Plane: mission not starting on its own

[Tom Pittenger]

On Plane v3.3.0 I'm seeing a new behavior, probably a bug in the new home scheme.

Old and good behavior:

Boot, load mission, (optionally reboot), set to AUTO - we're currently executing the mission step 1.

new, wrong, behavior

Boot, load mission, (or upon boot /w mission), set to AUTO - we're in lala land. I have to "Restart mission" before I can start a mission.

My first wp is TAKEOFF with 15deg pitch. In old behavior as soon as I boot up my ailerons/elevons pitch up signifying it's executing the takeoff. In the new behavior it seems like the mission is trying to execute, that is if I advance then it will go to wp2 and wp3 but I don't get the usual up pitch on takeoff unless I "restart mission" from Mission Planner.

This caused a crash on takeoff where my bungee drove my aircraft into the ground :( Bleeding edge strikes again!

-TomP

[Tom Pittenger]

See attached log

[Andrew Tridgell]

Hi Tom,

I've reproduced the issue. There main trigger for the problem is
entering auto before it gets GPS lock. A secondary problem is you have
ARMING_CHECK=0, so it disables all the safety checks for arming.

What happens is this:

- it enters auto, current WP is 1

- it then gets GPS lock. It sees a sudden alt change when origin moves
(this is a bug which I will see if I can fix)

- the sudden alt change briefly makes it think it has passed the
takeoff target altitude. It switches to WP 2

- throttle is still suppressed, so it is now on WP 2 and the bungee is
released

- for WP 2 it is not doing a takeoff, so it wants to gain airspeed
quickly, and puts the nose down. It crashes

I can reproduce it in SITL by starting up with SIM_GPS_DISABLE=1, then
entering AUTO, then re-enabling the GPS. It ends up in WP 2 and doesn't
do a proper takeoff.

I'll see if I can find why the relative altitude is briefly disturbed by
the GPS lock change.

Cheers, Tridge

[Andrew Tridgell]

Hi Tom,

> - it then gets GPS lock. It sees a sudden alt change when origin moves
> (this is a bug which I will see if I can fix)

I've now fixed the bug that caused this, and pushed to master. The
problem was that the altitude check for completion of takeoff was using
an absolute alt above sea level, not relative alt. When we get GPS lock
that absolute alt changes.

Sorry this bug crashed your plane!

I also recommend you set ARMING_CHECK=1.

Cheers, Tridge

[Tom Pittenger]

Thanks Tridge!