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
@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…
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)
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!
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.
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
@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!
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
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?
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.
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?
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.
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.
hi everyone, plane 3.8.0 is finally out, and I’d like to say a big thank you to everyone who tested tiltrotors for this release, especially the ground-breaking testing by @Rolf
I’m sure we will have a lot more improvements to come with tiltrotor quadplanes, but this is a great milestone!