Dual-motor tailsitters

[Rolf]

Hi Tridge,

logfile: https://www.magentacloud.de/share/ci7vxt6at6

If the plane is lying on the belly, in QSTABILIZE (or QHOVER) full throttle allows the controller only to turn motor PWM (RCOUT.C5/C6) up to maximal 1400.
That is not enough to lift the planes front. In MANUAL (or FBWA) modes the engine power control works well.

As soon as I raise the plane (with the hands without props mounted) nose up, engine power works also well. As soon as the plane is lying on the belly again, motor control is too weak again (red circle in the diagram).

Thanks for the look
Rolf

[lorbass]

I can confirme the issue of Rolf above with my Caipirinha.
Even worse the max Power with Ch3in 2000 flat is PWM 1220 and in Tailsitter Pos. PWM 1800
Indicated in MP on Ch5out and Ch6out.
ESC’s and Radio calibrated.

Therefore not lying on the belly but lying in the shelve.

Thanks for help

[tilt (research air)]

https://youtu.be/Rm01DeAgJMI… illusion auto, hover, loiter, land

[tilt (research air)]

yey Tridge ,
you around? sent logs
Rick

[tridge]

@tilt

https://youtu.be/Rm01DeAgJMI… illusion auto, hover, loiter, land

congratulations on your first QLOITER! Looks like it did pretty well.
The attitude tracking was excellent, the EKF was happy and all the sensors look good. Very good result!
Do you think you’re ready to try forward flight on the Illusion?

[tridge]

@Rolf

If the plane is lying on the belly, in QSTABILIZE (or QHOVER) full throttle allows the controller only to turn motor PWM (RCOUT.C5/C6) up to maximal 1400.

I’ve tracked this down to the angle-boost code. If you set Q_A_ANGLE_BOOST=0 then I think you’ll find that you get the full throttle range at any angle.
The angle-boost code doesn’t really make sense for a vectored tailsitter, as it is assuming thrust is to the front of the vehicle.
Sorry for not spotting this earlier!
Cheers, Tridge

[Rolf]

Thanks Tridge.
Just backyard tested and it works well
(For a complete flight it is unfortunately too windy today. Hopefully tomorrow)
Regards Rolf

[tilt (research air)]

Thanks Tridge[quote=“tridge, post:499, topic:15302”]
first QLOITER! Looks like it did pretty well.
[/quote]one interesting thing I noticed is as it leaned into the breeze it would descend and move forward as opposed to manual flight , would lean and climb as more lift is generated by the wing[quote=“tridge, post:499, topic:15302”]
Do you think you’re ready to try forward flight on the Illusion?
[/quote]almost, I think I will add some vertical stabilizer area for the 1st try having had some of these stright wings yaw to vertical when rolling into a turn in forward flight

[tridge]

@tilt

one interesting thing I noticed is as it leaned into the breeze it would descend and move forward as opposed to manual flight , would lean and climb as more lift is generated by the wing

there may be an airflow effect with the barometer. It thought that it stayed within 40cm of the desired height, but the video shows it didn’t.

@tilt

almost, I think I will add some vertical stabilizer area for the 1st try having had some of these stright wings yaw to vertical when rolling into a turn in forward flight

yes, good idea. We don’t have have support for differential thrust for yaw in forward flight, so it will be reliant on yaw stability of the airframe

[tridge]

@Rolf

Just backyard tested and it works well

great!

@Rolf

(For a complete flight it is unfortunately too windy today. Hopefully tomorrow)

I look forward to it. Good luck with the flight testing!

[tilt (research air)]

@tridge

We don’t have have support for differential thrust for yaw in forward flight,

we are going to need that, .01 to 5 %would probably do in my case and maybe mix with aleron/elevon

[tilt (research air)]

pull that off the shelve, sounds like Tridge fixed it !!

[jeffstreet]

SERVO#_FUNCTION =?= RC#_FUNCTION

This conversation mentions SERVO(1-6)_FUNCTION, but I only see RC(5-9)_FUNCTION in Mission Planner 1.3.48 (Advanced Layout) with Plane 3.7.1 on a Pixhawk1.

Feels like I’m missing something pretty basic. Would you please steer me in the right direction?

I tried a couple of things:

• Plane documentation shows SERVO#_FUNCTION, but not RC#_FUNCTION.
• This Copter post suggests the two are synonymous.
• Added SERVO#_FUNCTION parameters with a text editor, but Mission Planner rejected them upon trying to load the file.

Thanks in advance!

[Rolf]

@jeffstreet

but I only see RC(5-9)_FUNCTION in Mission Planner 1.3.48 (Advanced Layout) with Plane 3.7.1 on a Pixhawk1.

You have to load 3.8obeta5 firmware.

[Rolf]

Unfortunately we had an ESC burnup. Blessing in disguise that it happens at startup. Until the next test it will take about 2 weeks

Rolf

[tridge]

@tilt

we are going to need that, .01 to 5 %would probably do in my case and maybe mix with aleron/elevon

ahh, sorry, I must be getting forgetful in my old age. We do have differential thrust in fwd flight with vectored tailsitters. Just set RUDD_DT_GAIN to the percentage of differential thrust with rudder. It will mix from ailerons with KFF_RDDRMIX.

[tilt (research air)]

that"s great, Thank you !..forgetful? what were we talking about?

[jeffstreet]

Ah! Thanks a million @Rolf.

[lorbass]

Maiden “flight” of my Caipirinha now vectored.
Heavy oscillation of the Tilt Units produce a nice Yaw-dance. But far away from hoovering.
https://www.youtube.com/watch?v=R657OG74sQc&feature=em-upload_owner

Remarkable: Even with back touch during start, no damage.

And the Log file:
https://drive.google.com/open?id=0Bxldq38bfbqHRzhlTUhkMlA1M0U

Due to weak thrust, difficult to get Roll. With Roll cmd loose altitude (one mot reduce thrust, the other can’t because already on max.
I think it needs tuning, but which param in which direction?
Otto

[jeffstreet]

Foamboard Fixed-Motor Tailsitter

Here’s the maiden flight of a new foamboard fixed-motor based on the FliteTest Spear. It’s pretty manageable with the default tuning in QStabilize, QHover, and QLoiter.

Working on a write-up with plans, video, and log files.