[Canberrauav] QuadPlane code ready to test

Jack Pittar jpittar at bigpond.net.au
Mon Dec 28 16:22:16 AEDT 2015


Further info: In reading my last post I realize I may have given the wrong
impression regarding batteries.
Approximately 80gm of lead was added to make the plane balance where I liked
it to.
I used that battery because they are close to what is required, and I have a
number of them - not because it is the ideal battery.
Without the lead, I could have used a 6200mAh Zippy compact 3S 40C battery
at 451gm weight.
I would prefer to some more flying before deciding if 3S is enough.
My experience with batteries is limited, so I would leave it to more
experienced fliers to advise what batteries are most appropriate.
Jack.

-----Original Message-----
From: Canberrauav [mailto:canberrauav-bounces at canberrauav.org.au]On
Behalf Of Jack Pittar
Sent: Sunday, 27 December 2015 7:38 PM
To: Andrew Tridgell; SSUAV
Cc: canberrauav at canberrauav.com
Subject: Re: [Canberrauav] QuadPlane code ready to test


That's good news Tridge.

Sacrificial quadplane status:
1. The Firstar has been flown manually with RC only using the Telemaster
setup on the Taranis.
2. It has been painted for visability, white on top surface of wings,
vertical stab and horizontal stab. I have some orange stick-on material for
the wingtips.
3. The plane Pixhawk from the Vampire has been installed with external
safety plug, USB connection, and switch. It balances with a 4Ah 3S 60C
battery.
4. Right now I am working out how to program the CC Bec for 5.5 volts, prior
to firing up and doing the calibrations.
5. I have collected all the bits and worked out how I will go about
installing the quad components. I have decided to do it in virtually the
same manner as the Vampire, except that the single battery in the fuselage
will be used for both plane and quad.

I will be assembling the quad parts this week. Until they are ready, the
aircraft will be able to flown as a plane. I would like to establish a set
of parameters for it as an aircraft before converting it to the quadplane.
Although officially this is the Vampire prototype 3, I think the name
"Quadstar" would be more recognizable.

Jack.


-----Original Message-----
From: Andrew Tridgell [mailto:andrew at tridgell.net]
Sent: Sunday, 27 December 2015 3:16 PM
To: SSUAV
Cc: jpittar at bigpond.net.au; canberrauav at canberrauav.com
Subject: Re: [Canberrauav] QuadPlane code ready to test


> Sounds great Tridge,
> We would be keen to test drive your code.

ok, great, it's ready to test. Don't do the first flight on your most
valuable plane though!

It is the same as plane master but with 3 extra modes:

    mode 17: QSTABILIZE (same as copter stabilize)
    mode 18: QHOVER (same as copter alt_hold)
    mode 19: QLOITER (same as copter loiter)

You'll need to set the FLTMODE* parameters as numeric values as your GCS
won't understand these values yet.The code assumes a Quad-X frame, with
the motors on outputs 5 to 8. The normal plane outputs are assumed to be
on 1 to 4.

You can transition between any modes, fixed wing or quadplane. The
transition rules are:

 * if you transition to MANUAL then the quad motors will immediately stop

* if you transition to any other fixed wing mode then the quad will
   continue to supply lift and stability in a hover until you reached
   the ARSPD_FBW_MIN airspeed (or airspeed estimate if no airspeed
   sensor)

* once that airspeed is reached the quad motors will slowly drop over
   Q_TRANSITION_MS milliseconds (default is 5000, so 5 seconds)

You need to set Q_ENABLE to 1 to enable the QuadPlane functionality. All
QuadPlane specific parameters start with Q_, so just set Q_* parameters
as needed (they are very similar to the normal copter parameters). You
should also set SCHED_LOOP_RATE to 400 so it runs the main loop at
400Hz.

You could also try the Q_ASSIST_SPEED parameter, which can be used to
give quad assistance in any flight mode except MANUAL. Just set it to
the airspeed below which you want assistance. You can use that to fly
around at low speed in FBWA or CRUISE mode for example, or use it for
assisted takeoff.

I've tested it in a simulator and it works nicely, but it has never been
tried on a real aircraft. Let me know if you give it a go!

The code is here:

  https://github.com/tridge/ardupilot/tree/quadplane-wip

Cheers, Tridge



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