Oscillations during yaw right

[Ratamahatta]

Hi everyone,
I was wondering if anyone else is having this issue. Mini tricopter is oscillating in flight when I give it yaw right. Yaw left is working just fine.

Running triflight 0.5_beta2.
Tail servo: Savox SH-0255 6.0 Volt.

[LeoTheHuman]

There is a good chance you have your servo speed set up incorrectly. Did you use tailtune? What is your result? Video would also help.

[RCJim]

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[Ratamahatta]

Hi LeoTheHuman, I did run the tailtune. The servo speed is tri_tail_servo_speed = 366.
I’ll try to record a video tomorrow, but oscillations look like a PID issue (if i didn’t know better, that’s what I would attribute it to).

What’s strange is that yaw left works very nicely, only yaw right is weird.
It also is more noticeable during a drifting turn (in contrast to a sharp high speed turn).

[Ratamahatta]

Hi everyone, I have uploaded a video: https://youtu.be/OjOqRi3jyDQ
Look at oscillations when the copter is turning right.

PS: and forgive me the antenna being in the way.

[RCExplorer – David]

Is the tilt moving super smooth in both directions? Might be sticking when going to the right?

[lauka]

Please check my answer in github: https://github.com/lkaino/Triflight/issues/16

[Ratamahatta]

I figured it out. It was the servo feedback wire.
Once I disconnected the feedback wire, servo centering was way off (in the left direction), so I had to move a couple of spines before I could recenter it again.

After doing a tailtune it flies great, tracks like an arrow.

So, to me, it looks like hooking up a servo feedback wire (via a voltage divider?) messes up servo position sensing.

[LeoTheHuman]

So how exactly did you connect the feedback wire? What kind of values did you use on the voltage divider?

[Ratamahatta]

Feedback wire is connected to rc6 on naze32 and other end goes to ground via R2. Voltage divider is with R1 150 ohm, R2 1000 ohm.

[Author]

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