RTL: For VTOL first descend before transition #14728
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src/modules/navigator/rtl.cpp
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| @@ -318,7 +318,13 @@ RTL::set_rtl_item() | |||
| } | |||
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| case RTL_STATE_DESCEND: { | |||
| _mission_item.nav_cmd = NAV_CMD_WAYPOINT; | |||
| if (_navigator->get_vstatus()->vehicle_type == vehicle_status_s::VEHICLE_TYPE_FIXED_WING) { | |||
| _mission_item.nav_cmd = NAV_CMD_LOITER_TO_ALT; | |||
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@dagar For some reason this does not work for plain multirotors.
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The LOITER_TO_ALT logic was only implemented for FW.
RomanBapst
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Admin: Enhancement (improvement) 💡
Hybrid VTOL 🛩️🚁
Does tailsitter also have this feature? thanks |
…a transition Signed-off-by: RomanBapst <bapstroman@gmail.com>
NAV_CMD_LOITER_TO_ALT - this allows vtol to track the loiter circle during the transition instead of trying to fly to the landing position Signed-off-by: RomanBapst <bapstroman@gmail.com>
Signed-off-by: RomanBapst <bapstroman@gmail.com>
- descend to RTL descend altitude - transition - move to land waypoint - loiter and then land Signed-off-by: RomanBapst <bapstroman@gmail.com>
Signed-off-by: RomanBapst <bapstroman@gmail.com>
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This is how it looks like now (with this PR):
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@sfuhrer OK, so docs for return mode are here: http://docs.px4.io/master/en/flight_modes/return.html#vtol The current instructions basically say "If not in a mission landing, a VTOL in FW mode will always transition back to MC just before landing (ignoring NAV_FORCE_VT)." So the difference now appears to be that it does the transition explicitly at RTL_DESCEND_ALT.
You don't mention the behaviour around Further, the rest of the doc doesn't talk about transitions for VTOL much, but my assumption is that this really only applies for the cases where landing is not defined by a mission right (i.e. not when the return mode is to follow a mission path). |
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Very nice feature. Would be a good point to add wind direction into the procedure in order to fly with headwind from the end of the transition to the landing point. |
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This issue has been automatically marked as stale because it has not had recent activity. Thank you for your contributions. |
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@sfuhrer Is this still current? |
@RomanBapst |
When there is no planned mission landing available which makes the vehicle reduce altitude before transitioning then the vehicle will transition back to hover at the RTL return altitude as soon as it reaches the home position.
The RTL return altitude can be quite high (imagine the vehicle needs to clear a hill).
In most cases it's not desired for the vehicle to transition at high altitudes as hover flight uses a lot of energy. It would be better for the vehicle to descend in fixed wing mode and only transition once it's at the RTL descend altitude.
Now that we have path tracking during the transition it's actually ok to loiter down to RTL descend altitude and then transition. Previous concerns have always been that the vehicle drifts off during the transition as it was done in an open loop fashion.