Nearly everything works. I could even download a log.
After a certain time, the left stick doesn’t react anymore. When swiched the mode, it came down.
This was already the case days bevore.
No one hurt.
Here the log: https://drive.google.com/open?id=1Utt4RBQaWk5lZaa96KDNUaGAs3xmLIL7
In Ubuntu console nothing to see. Continuously indicating the height xx line per line.
The right stick reacts, to aircraft symbol in MP move. Will check again.
Viewing the log, I think Pitch Tuning is good. Only at the lift of it tilts by ~90 °
Edit:
Strange, I calbrated the Tx and modified the modes 2 and 4 from 23 (QAcro) to 5 (FBWA) and it lifts of as a moon rocket, slow, vertical.
In FBWA no luck, Transition good, but then it rolls left and sink.
Will test more to show logs.
@lorbass Maybe we’re using different versions of the BiWing RFX.
I just re-exported the model I’m using and pushed it up to:
SITL_Models/RealFlight/markw/Tailsitters/CopterTailsitters/BiWing/BiWing_JWL065_EA.RFX
cd to your SITL_models repo in Ubuntu and type
git pull
That should update it to my latest version. Then re-import it in RF8 (I think you’ll have to delete the old version first, or overwrite everything). And see if the new version behaves better.
I haven’t been able to figure out what’s wrong with the prop visuals. They are swapped left to right on both wings. This is a demonstration of why I say they’re swapped:
I spin up only the bottom left motor, and the bottom right prop (visual) spins. But the vehicle flips over to the right, indicating that it is really the left prop generating thrust, not the right.
If I swap the right and left visual frames for the engine, both props disappear.
Now I’m a little bit confused. Your Wing ist tilting, an mine hovers perfect. https://drive.google.com/open?id=10bmD18YoTd4lMRbtcW3jkdbO3MOJiZgw
Therefore I didn’t change my files in SITL_Models.
The date of all files I have in SITL_Models are 11.12.19. In RF8 I imported BiWing_JWL065_EA.RFX and BiWin9swapLR_JWL065backTorque witch is selected as Aircraft.
The quality of the Vid is not the best, I had it to record with a Handcam. The capture of the RF8 screen was not possible due to the decreased Frame Rate to 45 wich produced a wrong fligth attitude. And recording with RF8 produces a file which can’t be read by other programs and strange the mots are lateral as they are while designing in 3DS Max.
How do you record RF8 Screens?
Yes, I’m satisfied with your design, QHover makes fun.
But when I switch to FBWA, after a good transition it crashes immediately with left roll and high speed, also verry realistic, sorry.
When I switch to FBWA, it rolls left after a good transition and crashes. When I put the left stick full to the left, it rolls nearly not and I even could switch back to QHover and avoid a crash.
May be, the elevons are also crossed and the more it rolls, the more SITL steer to left?
@lorbass The video I posted yesterday is a demonstration of what happens in manual mode:
I manually throttle up only one motor, and the bottom right prop (visual) spins. I therefore expect the model to flip over to the left, But the vehicle flips over to the right, indicating that it is really the left prop generating thrust, not the right.
If you look at the video closely, you will see that only the bottom right prop is spinning.
This model flies well (for me) in all VTOL and FW modes, and it is the one that you should be using also. You would definitely benefit from updating to BiWing_JWL065_EA.RFX
Yes with this File Qhover and FBWA works.
Switching back to QHover it pitches to the ground, when high enoughe and full Throttle it can sometimes change to QHover. Do I have to exchange the Params too?
@lorbass The BiWing.parm file in SITL_models has also been updated, so try loading those parameters first. Just copy the updated file to ArduPlane/Biwing then start up SITL and type (in the mavproxy console):
param load BiWing.parm
mavproxy will print out the changed parameters as it loads the file.
This post: Copter Tailsitters
shows a plot of pitch and motor outputs for transitions from FBWA->QHOVER and back.
It should never pitch down during the transition to QHOVER, but there is a large overshoot on transition to FBWA (nose down about 45 degrees) that I haven’t managed to eliminate. @losawing Any advice on how to adjust parameters to reduce that overshoot?
@lorbass Regarding your question on recording RealFlight SITL sessions:
To record the whole screen (about 1920x1080), I use Flashback Express 5 at 15 FPS with mpg encoding. I get about 120 physics FPS in RF8 this way, and it seems sufficient for the BiWing model. This is a flashback recording exported to mp4: https://1drv.ms/v/s!AhgZy5vN7uiNgS-6yIGovksdKbyV?e=M1nFuW
In this recording I had Q_TAILSIT_MOTMX set to 3 instead of 15, and motors 3,4 shut down in FBWA. The forward transition also loses a lot of altitude (more than with all 4 motors enabled in FW modes).
To record just the RF8 window without impacting the physics framerate (much), I use the XBOX gamebar app for Windows 10. The RealFlight recordings are also useful, (and I think have zero impact on frame rate), but must be played back in RealFlight instead of a video player.
try to reduce q_a_rat_pit_I.
RF9 received but not tried yet. I am building a new model for flying in my garden…
edit: @kd0aij, I was too fast, if it is an integrator problem the parameter is the fw one, I am not sure of the name, ptch2srv_I
edit2: do you still have +2° for the rear wing. It probably gives a downward pitching moment and the integrator need some time to compensate. Could you try -1° instead ?
The problem was partly due to low ptch2srv_p gain. Autotune raised it from .33 to .95
With the higher gain, the overshoot is only ~12 degrees and is corrected pretty quickly. The best way to fix that might be to reduce the pitch rate in the second half of the transition, but I’ll have to look to see whether that is already implemented in the FW controller.
Changing top wing incidence to zero or -1 degrees reduces the overshoot, but the plane then has a strong tendency to pitch up at high speed; needs a lot of down elevon to compensate and outside loops become difficult.
Perhaps RealFlight’s simulation of pitching moment (Cm?) is not very realistic?
Sometime the biwing is a little sluggish, I will try the FF parameter to see if it helps.
Today I tested
Auto mission with takeoff and landing: OK
QRTL from hover and FBWA with the biwing facing rally point or not: OK
normal RTL with q_rtl_mode=1: OK
Weather vanning was enabled and Q_wp_speed=10m/s
Increase Q_VELZ_MAX to climb faster in qhover. It is currently only 150 cm/sec.
Tailsitters often have problems transitioning to hover when in high-speed knife-edge flight. Since transitions from qacro to other Q modes are not automatic, you must take care to avoid that situation. The safest procedure is to switch from qacro to fbwa first.
Or you could just establish a hover in qacro before switching to qhover.
To recover from high-speed knife-edge flight in qstabilize/qhover, either switch to fbwa to level the wings, or pitch nose-down until the wings are level, then gradually raise the nose while slowing down.
Thanks for the quick answer. Something strange.
I use QHover and FBWA. I can’t fly in Acro and during this flight I put full Roll and it made a bank of 45°.
In acro it would have rolled more. No idea why in the log it markes Acro because in Ubuntu it showed QHover and FBWA. Will test it again.
