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Apr 08, 2020, 11:46 PM
Registered User
I went ahead and mounted the KST servo on my baby-tri and now the ground tail tune gives proper numbers.
When I fly it, I get a 20Hz wobble mostly in the roll direction (from blackbox log) when I add throttle.
I played with the P and D and couldn't get it any better, until I lowered the I term.
It flies better, but I still get the 20Hz wobble when adding throttle.
I have spent about an hour messing with the PIDs, minimal luck.
I see the same 20Hz in the yaw, but slightly offset.
I don't know how to tune it out, I think one is causing the other, but not sure of the best way to figure it on on a tricopter.
Does anybody have a baby-tri that they could share their PIDs?
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Apr 09, 2020, 07:03 PM
Registered User
The recent software changes should not affect position hold in anyway. As for the feedforward gains, you're going to have to experiment with them. I haven't tried them.

I've also not moved my Baby Tri from dRonin yet. It's got an older FC in it with MPU6000 gyro, which does not seem to exhibit the attitude drift problem that the ICM gyros do on dRonin, at least not that I've noticed.

That said, my suspicion is the wobble is from the yaw, since on the Baby Tri the tail assembly is pretty high. I don't recall if you've got the impossible tilt on the baby Tri, but it helps lower the moving mass of the tail motor.
Apr 10, 2020, 03:31 PM
Registered User
I have the impossible tilt with bearings and KST servo.
I watched AndyRCs baby tri video and though I'd give his PIDs a try (I know they are usually completely different for other FW, but I thought I would try).
It about shook itself to death before leaving the ground. I then started lowering the PID values and my tri started flying better than it ever has.
I still see a very slight wobble mostly in the roll axis.
This is what I have for PIDs now, I'll keep experimenting
set mc_p_pitch = 35
set mc_i_pitch = 15
set mc_d_pitch = 15
set mc_p_roll = 35
set mc_i_roll = 15
set mc_d_roll = 15
set mc_p_yaw = 55
set mc_i_yaw = 30
set mc_d_yaw = 0
Apr 11, 2020, 09:07 AM
Gravity is patient............
Thread OP
David had a stock set of pids for the baby tri on his website back when he was selling it, perhaps it is still there. That's what I'm using and it works fine. But I haven't flown my baby tri in forever. In fact it still has the stock tail. But I never had tail problems on any of his tri's until we went to Dronin and INAV on the LR. But eventually that got worked out well by hex improvements (from our resident expert jihlein) and continued banging of my head against hard objects until it worked lol.
Apr 15, 2020, 04:45 PM
Registered User
Well it's slighty off topic, but I hovered my Tri LR earlier today using ArduCopter......and also my Tri V4......
Apr 16, 2020, 12:26 PM
Gravity is patient............
Thread OP
Quote:
Originally Posted by jihlein
Well it's slighty off topic, but I hovered my Tri LR earlier today using ArduCopter......and also my Tri V4......
I just got done learning INAV! Options overload. I WANT LESS CHOICE! lol
Apr 16, 2020, 12:27 PM
Steve
Quote:
Originally Posted by jihlein
Well it's slighty off topic, but I hovered my Tri LR earlier today using ArduCopter......and also my Tri V4......
So how did it go? I'm thinking about using arducopter myself.
Apr 16, 2020, 02:10 PM
Registered User
They both are flyable with the defaults in acro and stable modes. Tail is somewhat sloppy. Need to setup alt hold next as that seems to be a prerequisite for autotune. Then try autotune and see how they fly compared to defaults.
Apr 21, 2020, 02:08 PM
Registered User
Had a couple of big snow storms, so it put a damper on my testing.
One thing I have noticed is when I do the in air tail tune, I hear the beeps (is there a decoder sheet for what they are), and land, disarm and go out of tail tune, but when I look at the parameter tri_tail_motor_thrustfactor, it's still the same
Apr 21, 2020, 05:05 PM
Registered User
I was finally able to get the ArduCopter autotune to engage. I had it set for roll axis only. It's a bit more aggressive than the autotune in dRonin, I only let it swing a couple times in the backyard before canceling it. Need to get out to a field with it where there is more room. Hoping it does something good in yaw.....

Maybe I should start a new thread too....
Apr 22, 2020, 06:58 AM
Gravity is patient............
Thread OP
Quote:
Originally Posted by jhendrix
Had a couple of big snow storms, so it put a damper on my testing.
One thing I have noticed is when I do the in air tail tune, I hear the beeps (is there a decoder sheet for what they are), and land, disarm and go out of tail tune, but when I look at the parameter tri_tail_motor_thrustfactor, it's still the same
You have to have minimal copter vibration and minimal wind, and fly in a hover without touching the sticks otherwise it won't work. It's probably vibration or wind that is stopping it from working.
Apr 22, 2020, 07:55 AM
Registered User
stevea3342's Avatar
The last couple time I did the in air tailtune, the tri pretty much stayed in just one place while I tried to keep my hands off the controls for 10 seconds at a time. I'm not sure if that is right.
Apr 23, 2020, 01:13 PM
mutski
It appears my tail servo failed yesterday. The tail servo and mechanism are smashed, top plate cracked, two motors damaged, all the standoffs that held the electronics broke, battery bent. The VTX apparently came off before it hit the ground; I couldn't find it.

I had worked out good settings in Betaflight, switched back to iNav and had it flying reasonably well. Then I started having trouble with a wandering tail. The servo still ran smoothly and there was no play in the tail mechanism, so I was blaming it on iNav. I guess it was really a warning sign. The crash came with the first flight after I switched back to known good settings in Betaflight.

Oh, well, back to the drawing board.
Tricopter Auto Destruct (1 min 27 sec)
Apr 23, 2020, 09:27 PM
Gravity is patient............
Thread OP
Sorry to see it!
Apr 24, 2020, 11:34 AM
mutski
I am going to build again. I'm not sure what made the tail go haywire though. I'm safe if it was a Kakute failure - the FC is bent and broken. I tried plugging it into USB, and my mouse won't work while it's plugged in, lol. Fin! The next one will have your impossible tilt tail. Steve3342 has already sent me one. I think I'm also going to have the top plate cut with holes to fit the Runcam Split 3 board, and the bottom plate cut with the holes moved forward so that the Split 3 camera doesn't see the standoffs.


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