Servers by jDrones

Tiltrotor support for plane


(Zone FPV) #546

Thanks for the reply. The plane is packed away as we’re moving house and it’ll be several weeks before I can access it again, but thanks for the offer.


(Zone FPV) #547

Thanks again. For the next flights I’ll keep the rear motor stationary.


(tridge) #548

There are a lot of conflicting settings in this log. I’ll go through some of the more obvious ones:

  • ARSPD_FBW_MIN is set to 20, which is very high for a small plane like this. It never reaches that speed, so it never completes the transition to fixed wing flight
  • it is quite unstable even in hover. I suggest you don’t try to transition again until you have tuned the hover to be stable
  • you have a very strange mixture of SERVOn_FUNCTION values. For example, you have two lots of outputs for left and right tilt on channels 11, 12, 13 and 14, then you also have channel 10 set to motor tilt (which makes no sense on a vectored tri), then you also have left throttle set to channel 3, but no right throttle set (you don’t need left or right throttle set for a tri).
  • the airspeed sensor seems very badly installed, and is giving a huge amount of noise, I suspect it is affected by prop wash from the motors. I see airspeed going from 3m/s to 18/ms in a fraction of a second, which makes no sense
  • it doesn’t look like you have done any tuning of the hover gains

I suggest taking things a bit more slowly, fix up the above, and get hover tuned really well before trying to transition again.
Cheers, Tridge


(Lgh5054) #549

Hello tridge

Thank you for your reply

my copter used vectored tri

servo 10 is not use and servo 12 13 is use
servo 14 not use

i don’t understand you say “throttle set to channel 3, but no right throttle set (you don’t need left or right throttle set for a tri)” what is mean?

Please tell me how to read the log file and modify the pid

this is my copter


(PG) #550

I think this may answer one of my 2 questions:
my yaw control is still moving the tilt motors even when tilted all the way forward which would be bad in forward flight because it would induce roll and not yaw. Q_TILT_MAX description seems like it should turn yaw input off after specified angle but it does not. But this must be happening while im bench testing because it isnt reached any airspeed so as you mentioned, it never completes the transition? So then when flying, when min airpseed is reached and transition to FBWA is complete, does this yaw authority over the tilt motors cease?

second question still remains, i looked at the code and i dont see it… was forward movement with tilt rotors in vtol mode ever put into master? as rolf mentioned a while ago it seems pretty vital since moving forward as a tri/quad will give a forward down slanting rake to a plane…not good.

Thanks!


(PG) #551

this problem stated above arises moving forward/backward using yaw/tilt motor… both movements will be fighting the opposite elevons… but in a fixed wing vtol, holding level attitude is a must. maybe we need to either turn off elevon control in vtol and/or gain it up as airspeed increases…?

and I was reading through the tailsitter section.
“By adjusting the relative values of Q_TAILSIT_VHGAIN, Q_TAILSIT_VFGAIN and MIXING_GAIN you can adjust how much control you have from elevons and thrust vectoring in each flight mode.”

this sounds a whole lot like what i need my vehicle to do, but i need it to stay level from takeoff, toward flight, to land and only have the rotors tilt. i think we need that tiltrotor forward to move forward code…
thanks


(Zone FPV) #552

Thanks again for the suggestions. I rebuilt the plane following the maiden transition crash, changing the rear tilt servo to a fixed boom and adding stiffer elevons.

Over the weekend it performed several successful transitions. More tuning is needed, but it’s looking promising :blush:

Here is a short video about the rebuild and first transitions, both LOS and FPV: https://youtu.be/dF_YcthZm78

Param file: VTOL Wing Param List 20181003.param (16.3 KB)


(SkywingUav) #554

Tested the tiltrotor version of the VTOL code after seeing few success report from user of the NIMBUS platform. After about 6 months of developing the trirotor platform, its stability in hovering is almost perfect. Thanks @tridge and to all contributors for making this available.

(https://youtu.be/_N75MFCNHy4)


(Musa Wilmar) #555

Hi Rolf, i try to make one like this one, with front left motor CCW, front right motor CW, and rear motor CW… but it seams tobe spinning on the left all the time… vectored yaw is not working… is that any other setting that i missing?


(Musa Wilmar) #556

Ups… my mistake… i haven’t set the Q_TILT_YAW_ANGLE… problem solve…


(jacques_eloff) #557

Hi fellow VTOL fliers, hoping for some guidance here:

I am currently doing some testing on a Quadplane which has front tilting motors and have run into an issue with servo power. Our first attempt at transition failed as one of the front motors never moved to forward flight position and my initial thoughts are that the servos are too weak to deal with the gyroscopic forces involved. We could increase the BEC voltage from 7.2 to 8.4V which will take the torque up to the max rated power of 40Kg.cm but that is only an increase of 15% and will be too marginal in my opinion. Details of our setup are as follows:

Tilt servos are these: [These from Banggood], which are rated for 40Kg.cm

Front motors are SunnySky X3520 with APC 13x8 props.

We are looking into Volz servo options, eg. DA 15-N-HT. Has anybody had experience with these? Discussions with Volz indicate that they are more realistic about their rated specifications. There are also some Hitec options with similar specs to those in the link above. Anybody have any thoughts on those? What other servo options are available?

Any help/opinions/comments welcome.

Here is the Flight Log

Here is a video of the failed transition attempt: https://www.youtube.com/watch?v=K6RxfMDBjVQ


(Rolf) #558

Hi Jacques. Is there a logfile of the failed transition ?


(jacques_eloff) #559

Hi Rolf, I will post shortly


(Rolf) #560

Double postings are not so good, so I answer in your other thread Quadplane with 2 Front Tiltrotors - Servo Power Issues


(jacques_eloff) #561

Hi Rolf, I do realize that but did so on Greg Covey’s advice. Not everyone gets to read all threads.


(Wasim Akram) #562

Hi folks,
Here’s an update: After a series of ground testing, we’ve (Jacques and myself) have identified the problem - it was the case of an impaired BEC, and we’ve managed it sort it now. Thanks for your help.
Regards,
Wasim


(Greg Covey) #563

Hi,

I don’t see this defined in the Wiki so I was wondering what is the parameter (or parameters) that defines yaw via tilt rotor or yaw via motor speed (or a vectored yaw aircraft)? Is it Q_FRAME_CLASS? Are there any illegal combinations?

Cheers and Happy Holidays!


(Peter Hall) #564

Hi all,

I have done a PR to add differential thrust in forward flight using the RUDD_DT_GAIN parameter, it has been tested for a tricopter style tilt rotor, would be great if someone with a quad type tilt rotor could also test it,

I can build the code for your flight controller,

Thanks


(Wasim Akram) #565

Hi Pete,
We can test it on one of our quad tilt-rotor builds but we won’t get to it until the 10th of Jan. If that’s okay with you, we can undertake this task?
Wasim


(Peter Hall) #566

Great, what flight controller are you using?