Servers by jDrones

Tiltrotor support for plane

(Greg Covey) #369

Hi,

Look at the posts just above the one of your VTOL plane image. Both Rolf and Pete have recently been successful with the tilt yaw servo control.

1 Like
(Basem Hasb) #370

thanks Greg
i have a little problem in Q_stabilize mode the aileron servos work and elevator too but in tricopter platform those servos must be off , anyone have deal with that problem before ??

(TsuyoshiKawamura) #371

Hi,

I’m a ArduPilot user in Japan.
I tested QLOITER by replacing E-Flight Convergence with Pixhawk v1.
This is a test video.
I would like to try AUTO next time. I have three questions.
· Is this the Waypoint setting correctly?
· Is DO_VTOL_TRANSITION mandatory?
· Will the motor return to vertical automatically with RETURN_TO_LAUNCH?
1, VTOL_TAKEOFF
2, DO_VTOL_TRANSITION
3, WAYPOINT
4, WAYPOINT
5, RETURN_TO_LAUNCH

1 Like
(Gabriel DeVault) #372

Hi Folks! I am working on a tilt wing VTOL plane.

Is arudplane/pixhawk capable of controlling a tilt-motor/tilt-wing like this vehicle?

http://ares-rc.com/z-line/v-hawkx4/features.asp

Any tips/direction would be appreciated.

(PG) #373

@Rolf @tridge
I made some decent progess and finally did a ‘maiden’.
I still need to mess with the PID a bit.
this was actually the second test. the first one, the rotors are tilted forward too far in hover rest position, so it wants to always creep forwards, and i tried to change the servo function trim and they dont move…
so i changed the tilt angle back to 0. but when they are at 0, vectored yaw doesnt give any output… so i tried 1 degree, and i get a HAIR of movement… almost as if the tilt angle number represents also how much vectored yow control you have too… i tried -5 and it doesnt like that lol.
so i have two questions. how can i get the tilt angle to be 0, and get vectored yaw?( or how else can i adjust the hover rest position of the motors?)
and also how far along is the [motor tilt to control forward movement] code coming? I’d much rather use that to transition forward as i want my aircraft to remain level while transitioning…

Thanks for all the support!!!

1 Like
(Rolf) #374

Hello Pete

The oscillations are probably caused by too high Q_A_RAT_PIT_P and Q_A_RAT_ROLL_P gains.

Vectored yaw - make sure you have specified your Q_TILT_YAW_ANGLE correctly:
(SERVOn_MAX/MIN may be interchanged depending on how the servo is installed)

Regards Rolf

2 Likes
Nimbus 1800 vectored yaw VTOL maiden
Nimbus Tricopter VTOL
(PG) #375

what youre showing me seems to make sense, but im seeing the opposite in my set up…
the higher the tilt yaw angle i put in, the further forward they go, rather than back!

(tridge) #376

yes, and that is consistent with what @Rolf said.

It initially tries to centre both rotors (ie. both pointing straight up). To do that, it needs to work out what PWM it needs to put in to achieve the centering. If you look at the nice diagram from Rolf, you’ll see that as Q_TILT_YAW_ANGLE increases that the PWM needed to make the servo vertical moves more towards SERNOn_MIN.

The way the maths works is this:

  • for an example, lets assume Q_TILT_YAW_ANGLE is 15
  • it knows that at SERVOn_MAX that the servo is at -15 degrees (15 degrees angled back).
  • it knows the total angle the servo goes through it 90+15 which is 105 degrees
  • so to get it straight up, it needs to move the servo to SERVOn_MAX-(15/105)*(SERVOn_MAX-SERVOn_MIN)

As you can see, if you increase Q_TILT_YAW_ANGLE without actually changing the servo movement then it will cause the rotors to tilt fwd more.

In other words, Q_TILT_YAW_ANGLE is something you measure about the frame, not a desired angle. If you want to change the desired angle you need to move the servo endpoints.

1 Like
(tridge) #377

yes, that should work. You’d need to set the tilt mask as 15 (which means all 4 rotors tilt)

(tridge) #378

I don’t know what that means, sorry

no, it is only rarely used. Normally you set Q_ENABLE=1 and all waypoints are treated as fixed wing targets. You only need DO_VTOL_TRANSITION if you want some waypoints to be multirotor

not by default. It will do that only if you set Q_RTL_MODE=1

(PG) #379

@tridge thanks a ton for the clarification.
I got it all working the way it should! Now I am having a problem with the PID. I got the osilations out, but the thing wants to flip forward on takeoff…
either the controller isnt listening to the accelerometers and gyros and wont correct, or i have my PID gains all wrong. (which i dont understant because shouldnt it be at least barely flyable with the stock PIDs?
OR my rear prop is overpowering for some reason…
@rolf have you had anything like this happen to you while setting up?
What is the best method for tuning a scratch build tricopter with vectored yaw!?
seems like any adjustment i make does nothing…
Thanks!

(Rolf) #380

Hello Pete,

Does the frame fly with the old PIDs? It will probably be the best to upload a logfile.

(TsuyoshiKawamura) #381

@tridge Thank you for comment.
I succeeded in automatic navigation of Convergence using ArduPilot.

2 Likes
(PG) #382

ill attach a log. Very confused, the thing wont keep itself in the air. I cant lift it off the ground because it wants to just flip straight forward, so i hold it with my hand and keep it level and give it throttle and it will be just barely okay in the air, but if i try ot let go, it wants to spin in either direction(inconsistent) and the left side usually dips down. basically it cant takeoff right and it wants to spiral crash .
in thought the autopilot should just stabilize itself? then the tuning dials in the control ‘feel’???
Im in Q_Stabilize

2017-06-24 14-40-51.tlog (660.8 KB)
2017-06-24 12-07-00.tlog (396.1 KB)

I moved the CG rearward a bit and it helped it from flipping forward, but the thing still doesnt want to stabilize and fly in the air on its own at all…
any ideas?

(tridge) #383

congratulations! Great to see it flying

(tridge) #384

A dataflash log is preferred instead of a tlog.
For stabilisation, you need to check all the directions are right in a hand-held test, with the sticks neutral:

  • when in QSTABILIZE mode, roll the vehicle right. The right motor should increase thrust, the left motor should decrease
  • then roll it left, the left motor should increase thrust, the right should decrease
  • then tilt the nose up. The rear motor should increase thrust
  • then tilt the nose down. The rear motor should decrease thrust
  • now rapidly yaw the vehicle to the right (so nose goes right). As you start to yaw it, the right motor should tilt forward, the left motor should tilt back
  • now rapidly yaw the vehicle left. The left motor should tilt forward, the right should tilt back

Then do all the same tests, but on without holding the vehicle, instead have it on the ground, and use the sticks. Use a small amount of throttle, but not enough the take off. Check that as you use roll, pitch and yaw that the motor outputs are trying to move the vehicle in the right direction.

1 Like
(Gabriel DeVault) #385

Thanks for the feedback and apologies for my ignorance. Which channels do my motor controllers plug into? Which channels do my servos plug into? What parameters do I have to set to make that work. Is there documentation which describes this setup, and also what tilt masks are available?

(Sstage) #386

10ga wire and xt60 connectors on my battery werent nearly enough… Solder melted off the power module and sprayed the open connectors on my pixhawk. Bridging some of them. Just ordered some xt90 connectors so ill see how that goes.

(David) #387

@tridge,

Did you ever get the fireFly 6? Very interested to read your observations. I have a FF6 with AVA and am considering a switch to plane.

One of the features birdseyeview markets is wind assist. Do you have any thoughts about how this capability compares to wind corrections with plane?

Generally I am happy with Ava, but I don’t like that they stripped out mission planner functions.

Thanks for all your contributions to this community.

Dave

(Rolf) #388

Meanwhile, we are fully satisfied with the tiltrotor firmware.

Next, Walter and I want to transfer the experience to a high-performance plane.
For the medical express 2018 unfortunately the preparation time for us is too short,
so we wish tridge and his team all the best. :wink: