Plane supports being armed, in takeoff logic and not spinning the motor
until the moment the safety button has been pressed. Unfortunately
because the safety button is required to be pressed for soft arming this
results in the plane updating home position while the user moves the
vehicle or is holding it to throw the vehicle which will can result in
several meters of altitude error from where the user expected home to
be.
Because the normal approach to plane is to have activated the safety
button before arming the aircraft this is not expected to be a behaviour
change for most users, but an improvement for people who use the button
to initiate a takeoff.
this is most often implemented as dual-motor differential thrust, and
we don't want to do surface speed scaling for that.
In the future we'll move this scaling so it can be done on rudders for
3D planes
When we are landing a sink_rate < -0.2f means the vehicle is climbing,
which should never happen during an approach for any supported landing
type (slope or deepstall), and on hard impacts with the ground its
common for the vehicle altitude to be projected to low and climb back to
the correct altitude slowly (but at a higher rate). This changes the
check to only consider sinks while on approach as acceptable.
added scaling of control surfaces by throttle when in hover. This helps
the controller remain stable over a wide range of throttle levels, such
as when descending or rapidly climbing
when Q_RTL_MODE=1 in a quadplane use RTL_RADIUS as the distance to
switch to QRTL mode. We navigate to the destination using direct
waypoint navigation instead of using a loiter circle.
when on the ground in an auto-throttle mode lik FBWB or CRUISE, we may
have the throttle suppressed. In that case we should not run the
multicopter controller on quadplanes, or it may build up control which
will then apply on takeoff. This is particularly severe for aircraft
that are not level on the ground, such as taildragger quadplanes
Fixes https://discuss.ardupilot.org/t/quadplane-flips-on-takeoff/22095
many thanks to Sriram for reporting
