Hi LibrePiloters!

I have a Revolution Mini FCC that I've been learning with, and I really appreciate all the awesome information on this forum.

I'm building a VTOL aircraft and I'm trying to figure out if there is a way to change the virtual attitude relative to the board while the vehicle is in flight. My vehicle is not a tiltrotor. The entire fuselage will pitch 90° when flying horizontally. If I could change the virtual attitude when I switch from vertical flight to horizontal, then I could use attitude flight mode in both. Is this possible? Any ideas?

Thanks for any help!

karla

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Cool!
Can you explain a bit more about your craft?
What is it and how can you tilt the whole thing 90 degrees?
K

There isn't an official way to do this.  The recommended way would be to hover in Attitude mode, then switch to Rate mode and do the transition by RC control.

It may be possible to make a uav file that only has RotateVirtual settings in it, and bypass some safety checks and import this file (without saving to flash) via OpLink while flying.  I don't know whether this can be done while armed, without making code changes, and whether it would even be ignored if you could do it.

Thanks for the replies!

The vehicle is a one-off custom design. It's kinda odd, but you can think of it as simply a tailsitter airplane. The control surfaces will be used to tilt the whole aircraft.

I think I understand the idea of using Attitude mode in hover and switching to Rate mode for forward flight. It's not ideal, but I think it would work. What I'm really after is some level of stabilization while in forward flight. I don't want to have to manually level the aircraft.

In theory, I understand your idea of importing a uav file, but in practice, I'd have no idea to implement that.

Another thing I'm trying to work through is the control assignments. Yaw in hover becomes roll in fwd flight. I'm trying to switch transmitter stick assignments when I switch flight modes. I didn't really see a way to do that in LibrePilot, so I was trying to program that in my transmitter (Turnigy 9XR Pro). Any ideas on that?

Thanks again!


There is a "disable safety checks" somewhere in System -> Settings.  I don't recall, but I doubt that it would let you change settings with the vehicle armed.  Doing that would probably require code changes.

The fancy transmitters allow you to do just about anything.  I would expect one would allow you to set a switch to change to a new "flight condition" (IIRC that's what it's called by Futaba) where you had different sticks for the controls.

The assumption was that you would mentally switch modes and hover it with rudder/elevator like you would a 3D airplane.

karla

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Another thing I'm trying to work through is the control assignments. Yaw in hover becomes roll in fwd flight. I'm trying to switch transmitter stick assignments when I switch flight modes. I didn't really see a way to do that in LibrePilot, so I was trying to program that in my transmitter (Turnigy 9XR Pro). Any ideas on that?

Ah, a tailsitter airplane, that has got to be the most simple way to design a VTOL fixed wing, from a mechanical point of view. Elegant, no rotors with tilt mechanisms and servos doing this and that needed.
I am pretty sure I can do the set-up you describe in the transmitter using Deviation SW, (http://www.deviationtx.com), or with some help from that community. Rudder/elevator change functions in Hover respectively Forward flight modes. That should make it possible to fly Attitude in both modes? If not then use rate for hover and attitude for forward? However, this does not help you much since you use other TX SW. Sorry about that, but the wizards at Turnigy 9XR Pro, might know how.
« Last Edit: July 12, 2017, 08:11:50 am by karla »

Changing the transmitter to switch which channel is connected to which stick won't rotate the Attitude hover angle.  Think what happens if all sticks are in the middle and you switch the sticks around.  All sticks are still in the middle and the FC doesn't see anything different, yet you want it's idea of what level is to rotate 90 degrees from hover mode to forward flight mode.  :)

karla

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I'm building a VTOL aircraft and I'm trying to figure out if there is a way to change the virtual attitude relative to the board while the vehicle is in flight. My vehicle is not a tiltrotor. The entire fuselage will pitch 90° when flying horizontally. If I could change the virtual attitude when I switch from vertical flight to horizontal, then I could use attitude flight mode in both. Is this possible? Any ideas?

It may be possible to make a uav file that only has RotateVirtual settings in it, and bypass some safety checks and import this file (without saving to flash) via OpLink while flying.  I don't know whether this can be done while armed, without making code changes, and whether it would even be ignored if you could do it.

I tested with a RevoNano board connected to GCS with a USB cable, and did File, Import UAV Settings...
And it works (loading it to ram) even if the the Safety settings are on OR off, even if the board is in Armed or Unarmed state, at the time the command is given. The only thing I changed in the two files was Attitude, Settings, Roll 90 degrees respectively Roll 0 degrees.
I can see the horizon in the PFD flipping.

Interesting, however, I think if want to explore this further, should use great safety care...
« Last Edit: July 16, 2017, 01:11:20 pm by karla »

Time for a bullet proof codpiece and shin guards.  :)

karla

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Haha, maybe like this...


 it seams like it would make since    to set up the board in the aircraft to forward flight in altitude mode (since the board keeps  the craft upright) and switch to rate mode to land and take off.  my multirotor  will fly in any orientation in rate mode until it crashes or I bring it back  to level so if your plane was designed to fly a certain way and it got proper thrust and or lift than you should be able to fly any axis/angle you want  as long as you want and the board only does what it's told to do no matter if its upside down it doesn't try to auto level.  Hopefully I have  explained  what I can see in my head properly. If not let me know and I will try to elaborate. It might be difficult to hover depending on the crafts stability and design. Good luck and let us know how thing work out

Yea, he is wanting auto leveling in both hover and forward flight.  Using Rate mode for at least one has already been discussed.  :)

f5soh

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Replying to the first post, for a VTOL with vertical takeoff the following settings should works:

- Stabilization > Advanced > Pitch > Attitude response to 90°
- Be sure the Stabilization > Basic > "Zero the Integral when Throttle is low" is checked
- Input tab: adjust one flightmode with Roll - Rate, Pitch - Attitude, Yaw - AxisLock as a "takeoff flightmode".

While taking off you need to maintain the Pitch stick backwards, apply Throttle and after the flight started vertically you can slowly release the Pitch stick, fly horizontally and switch to another flightmode/stabilization behavior.

A specific bank can be assigned to the "takeoff flightmode" allowing special stabilization PID in vertical configuration and the two remaining banks used for normal Attitude/Rate/... flightmodes.



Wow guys, I've been out and about lately and hadn't checked back in - but thanks for all the replies! You all have some very interesting ideas. I was pessimistic I would be able to figure this out, but now I'm thinking this might just work.

I'll be sure to be safe in testing, even though I don't have a suit of armor!  :D