The vertical descent has begun, then its slow last part
What ArduPilot says:
- Land descend started
- Land final started
“Land descend started”: in position2 (hovering over the landing point) the aircraft came within 2 m of the point at under 3 m/s and now descends at Q_WP_SPEED_DN (150 cm/s by default). “Land final started”: the height above ground is under Q_LAND_FINAL_ALT (6 m by default) and the descent is Q_LAND_FINAL_SPD (0.5 m/s by default) from here to the ground. The height comes from a rangefinder when one may be used for landing; without one it is the height above the landing waypoint's altitude, or above home in QRTL. QLAND goes straight down and prints neither line.
What to do, most likely first
The slow part starts too high or too late: with no rangefinder the ground is assumed to be at the landing waypoint's altitude (home in QRTL), and the real ground is higher or lower.
FixFit a downward rangefinder and allow it for landing (
RNGFND_LANDING), or give the landing waypoint the right altitude.
Parameters to look at
| Parameter | What it is |
|---|---|
Q_WP_SPEED_DN | Waypoint Descent Speed Target |
Q_LAND_FINAL_ALT | Land final altitude |
Q_LAND_FINAL_SPD | Land final speed |
RNGFND_LANDING | Enable use of rangefinder |
The code that sends it
Land descend started
ArduPlane/quadplane.cpp QuadPlane::verify_vtol_land() · Open in ArduPilot Plane-4.7.1
Land final started
ArduPlane/quadplane.cpp QuadPlane::verify_vtol_land() · Open in ArduPilot Plane-4.7.1