this fixes a bug where TECS maintains its slow integrator while in a
VTOL hover mode in AUTO or GUIDED.
Among other things this affects PAYLOAD_PLACE and
DO_VTOL_TRANSITION. In those states the height can change while
hovering outside the control of TECS. When TECS regains control in a
fwd transition then can lead to a very large height loss or gain until
the TECS integrator can catch up
this sets up the vwd integrator more reasonably when we are in
POSITION1 stage of VTOL landing. We need to have enough throttle to
cope with a headwind, but want it lower when we are at or above our
target closing speed so can minimise the amount of pitch up
This also makes the landing_desired_closing_velocity() consistent with
the landing speed used in approach, using average of airspeed min and
cruise speed if TECS_LAND_ARSPD is not set
The target airspeed for TECS during airbraking is now set to
ARSPD_FBW_MIN, on the basis we are trying to slow down to min speed,
and we have VTOL support which should prevent a stall.
To cope with a high headwind where ARSPD_FBW_MIN is below the headwind
we now check for too low achieved closing speed and switch to
POSITION1 which can use vfwd to get to the landing location
During POSITION1 back-transiton we scale the MC angle P gains with
airspeed to reduce the chance of oscillations. At higher airspeeds the
fixed wing controller dominates so we should use the fixed wing angle
P gain.
if the user hasn't set TECS_LAND_ARSPD then we can use an airspeed
between ARSPD_FBW_MIN and TRIM_ARSPD_CM when on approach
this also fixes landing_desired_closing_velocity() to never go above
the landing target speed, so we don't try to speed up if we are
starting the landing sequence too early
this is equivalent to copters WP_NAVALT_MIN parameter for takeoff. Not
implemented for land yet
this is useful for vehicles with significant GPS velocity noise on
takeoff, preventing dragging the landing gear
this fixes a case where we can get false positive on the landing
detector for quadplanes.
The issue happens if we cross the LAND_DESCEND to LAND_FINAL threshold
while pilot repositioning is active, with stale information in
landing_detect.lower_limit_start_ms as we don't run should_relax() in
LAND_DESCEND
Andrew Tridgell
Henry Wurzburg
Peter Barker
Iampete1
Leonard Hall
Jeremy
mattbooker
Mirko Denecke
Michael du Breuil