30 August, 2019 at 09:22 #63457
After a few flights and the first autotune parts I’m now at tuning the tail.
I know there is a thread about tuning the tail, which is a big part of a Tri if you ask me.
Anyone have some good starting values after autotune and where to input them?
Asking for a friend who is new to dRonin 🙂
I see some crazy high numbers at rate yaw P and I that are marked as yellow in my tab.. indicating to me that the values are insane.
Can some one post screenshots of their pid etc settings so i can at least compare I don’t have any strange numbers in there.
And what are the basic steps to tune the tail?1 September, 2019 at 19:15 #63474
Tuning the Tri lr
Well, here we go.. getting it to fly the way it was designed.
First step was to run a servocalibration on the bench.
Not that in the video David calles it Tailtune, but it is now called servocal.
This measures the servo speed and adds it.
Next step I did the first flight and in hover mode activate autotune.
It will start measuring and doing all sort of stuff for a minute, then disarm and went to the computer.
Accepted the autotune measurements.
The yaw P an I are a bit high, and after a test flight and reading the forum I discovered it is best to lower these.
My autotune Yaw P was 0.0086something and I 0.03ish
I found a post on the forum with some settings made it respond better.
I now have the yaw P set to 0.0068 and the yaw I to 0.0035 en the D to 0
Next stop was to do an inflight Tailtune (servocal) but I cannot get it to do that.
After the inflight tailtune you should get a Thrustvalue for the tail, but mine stays at 13.6
If anyone is reading this, did you get the tailtune to work inflight and what was you Thrustvalue after measuring??
This week the weather will be blegh.. so probably cannot do any testflight.6 September, 2019 at 15:45 #63508yumemi5kParticipant
I’m also using EMAX ECO 1700KV and mine is 9.68. Tailtune (Servocal) completed on first try for me. Did you land -> disarm -> exit Servocal in the particular order? But mind you my copter hovers with some tail wagging so maybe my tail related values are quite a bit off.
The weird bit is that my copter flew beautifully after autotune until yesterday, but today I notice a slight chattering noise and some tail wagging. Now the ghost hunt begins…9 September, 2019 at 14:38 #63521
I’ve been reading and thinking, maybe the inflight servocal does not initialize because there is too much movement.
Do you have a beeper attached to your Tri? I don’t have one as I was hoping the esc would do the beeping with this kind of setup.. but they don’t.
I will try your tailtune value.
Do you fly 3S or 4S?9 September, 2019 at 16:49 #63522yumemi5kParticipant
I fly 3S lipo. I have a beeper attached and I’m not sure if motors can beep during flight at all, as ESCs essentially wiggle the magnets around at hearing frequency to generate a beep, which I doubt is possible mid-flight.
My buzzer beeped a few times during servocal, and I actually did a new measurement today hunting the tail wagging and the new value is 7.9 ish. I’m flying a 2200mAh 3S lipo.
I’m currently getting some slow and minor tail wagging in hover which gets worse during forward flight. I’ve configured TxPID and will try tuning it out myself. I’m currently running 5V on tail servo which I also plan to change to 6V at some point.17 September, 2019 at 07:37 #63648
Did a couple of test flight last week, and it flies really well.
I manually changed the thrustvalue to 7.9 and will test again this afternoon.
It is still wagging it’s tail at higer speeds making the Tri unusable for recording any flightvideo.
I hope I can somehoe solves this or else I’m going start looking at alternatives like inav or betaflight to see if that fixes the tail issues.18 September, 2019 at 21:47 #63708zophonParticipant
I’ve summed up every info I could find to get my tricopter LR to fly here (noob disclaimer). The relevant bits would be :
On a calm day, I had no trouble completing the autotune, everything went fine. I did several because I crashed and I tried different batteries and so on… The last autotune I did delivered following results. This could be used to compare with other setup, but it is by no means a reference point or values to put directly in your copter.
Roll P 15 I 55 D 27
Pitch P 25 I 91 D 54
Yaw P 56 I 349 D 10
Roll and pitch values are directly from the autotune, but I modified a bit the yaw values:
I think I halved the yaw P term after the advice in post 62240 (thanks @vantasstic) and 62271 (thanks @billyd) and lowered a bit the yaw I term (it was over 400 or 500 with the autotune).
I followed the advice on zeroing the yaw D term, but then I tried a first incrementation at a value of 10. Seems allright, probably not perfect, but fine.
Well let’s call it ServoCal since it is the new name. It went without problem to get a value different from 13.8, but it was a bit harder to get a good value. More on that in the next section.
With the newest build, the beep pattern for successful calibration after landing is 2 beeps pause 2 beeps etc… if I am correct.
Tilt mechanism and friction
A thing that I did not quite catch on my attempt is characterising the right fricton to have in the tilt mechanism. David said to “file it in order to have not too much friction, but you don’t want it too loose”.
On my first attempts to tune the copter (autotune and servocal), I ended up with a nice tune in roll and pitch and what I thought to be correct tune for yaw. I got a bit of tail movement, and if I hit the throttle hard there was a significant amount of tail wag. The HoverThrottle was at about 0.40 something. But the MotorThrustFactor was worrying me as it was over 40!
Reading further in the forum, I saw one or two reports of MotorThrustFactor being 8, 9 or 10-ish values (post 62431 for example)… So after a crash that had broken the zip-ties of the tilt mechanism I went back to the workbench and tried to have less friction on the tilt mechanism. And already at the servo speed tune step I saw some changes : the speed measurement were much more consistent : 190°/s + or – 3°/s. Before I had done this three times with a max 217°/s and a low 180°/s (I think), I kept the max value, because well, the more the better…
After an autotune and a servocal, here it is : MotorThrustFactor at 10.5! And even less tail wag when I punch the throttle (It’s visible that the servo is doing its thing, but the tail doesn’t go crazy). I am not sure that this corrects avery vibration problem, but the tail behaves nicely (noob point of view ? ).
So here might be an indication that the friction is too much in the tilt mechanism:
– Your MotorThrustFactor is too high (could some confirm that a 10 ish value is good, and that 20 to 40 is way too high?).
– Check for a consistant speed at servo setup.
So if you want to redo an autotune, I would advise to reset the values to default in dronin (my yaw would get crazier and crazier after each autotune…) and halve the P and I term of the Yaw, and zero the D term.
For servocal, check if the speed is consistent at the “speed measure” step (to erase this possibility of tail wag).) Then servocal in the air, I just got in the air, hovered, waited 30s and landed, disarmed and then exited servocal. It just worked…
20 September, 2019 at 11:25 #63732
- This reply was modified 8 months, 2 weeks ago by zophon.
My tailservo speed measurments are almost the same I believe it is now set to 190°/s
My autotune’s where great and it flies really well.
Got the Yaw P and I from the forum from the exact post you used and set D to 0.
I now manually set the tailthrust and plan on doing a few testflights this afternoon.
The plan is to post some uncut raw footage from the onboard Tarsier. I still have slight tailwagging that is visible when you fly straigt and fast towards a fixed point.
If I can get rid of this tailwiggle it will be a perfect platform to shoot fpv footage.20 September, 2019 at 19:47 #63743
Here’s some raw footage from the last flight.
As you can see the tail still keeps waggin’ around.
What value do I tweak to get to tailservo to respond less to the yaw movement.
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