Hi! I am trying to design a controller for landing a fixed-wing by going into deep-stall. I would like to use as much as possible from ArduPlane. As the AutoPlane is very good at avoiding stalls I suspect that none of the modes (except MANUAL) would be suitable for such a maneuver. Mainly, I need to directly set the desired set-points for the pitch-angle without any safety mechanisms kicking in when the plane stalls.
Is there a mode that I can use for this, by setting the right parameters or would I have to create my own mode? Any ideas would be highly appreciated!
Bank angle limiting - Stall prevention is active in the following modes:
•FBWA
•FBWB
•AUTOTUNE
•CIRCLE
•RTL
•AUTO
•CRUISE
•LOITER
•GUIDED
Note it wont stop one from occurring through lack of throttle unless covered by TECS. Also the above I wouldn’t want to limited anyway as it will prevent you from entering a stall during a turn. I would envisage the deep stall landing would be on a straight line to reduce tip stalls (and resulting spin).
Again TECS wont stop it entering a stall if the parameters aren’t right. In FBWA and Autotune it has a nose down modification dependent on the throttle position for straight flying.
I think you could actually do a deep stall if the airframe handles it currently - without any changes to the FW. If you want an automated landing mode I’d suggest you make a new mode (Deep Stall Land Mode) to test out any changes you want - use land mode as a basis and change as required. Arduplane will do it’s best to assist you in not stalling but it wont stop it occurring - if you want one it will occur. I’ve done it before in FBWA to test a plane and how it will handle it before handing control over to a newer pilot. I also test stall all my planes in Manual mode too just so I know how it behaves. Deep stalls require an airframe that wont tip stall, this can be a challenge.
I want the landing to be autonomous, but I can put parts of the controller outside ArduPilot, on another hardware. I just want ArduPlane to handle the low level controls. Do you recon FBWA mode (with STALL_PREVENTION off) will allow me to pass in a pitch reference to the elevation controller in ArduPlane? If not, is there any guide out there or any experience on how to create a new mode for ArduPlane? There is a tutorial for ArduCopter (dev.ardupilot.com/wiki/apmcopter … ight-mode/), but the structure of the code for ArduPlane seems to be quite different.
I want the landing to be autonomous, but I can put parts of the controller outside ArduPilot, on another hardware. I just want ArduPlane to handle the low level controls. Do you recon FBWA mode (with STALL_PREVENTION off) will allow me to pass in a pitch reference to the elevation controller in ArduPlane? If not, is there any guide out there or any experience on how to create a new mode for ArduPlane? There is a tutorial for ArduCopter (dev.ardupilot.com/wiki/apmcopter … ight-mode/), but the structure of the code for ArduPlane seems to be quite different.[/quote]
From memory the tutorial is still valid and should apply to what you are doing (yes it is for the copter code but the plane code is similar). Having said that I have not added a new flight mode to the plane code, I’ve only done it in Copter as a ‘can i do this successfully’.
I would try to get the FC to do as much as it can, it has access to all the sensor data. It can react much faster than a companion computer will.
You will also need to modify STAB_PITCH_DOWN if using FBWA as the basis, so yes if you use FBWA with the STAB_PITCH_DOWN modified you should be right.
All I can say is that get your airframe right first off because a deep stall is hard for it to control. I’d suggest you test it in manual and try to control it first off at a few mistakes high. Personally I’d prefer to use a parachute for smaller spaces.
