V3 Tricopter with Naze32 Tuning

x0054

Senior Member
Hi all,

I recently finished building one of David's V3 tricopters with the integrated Naze board and got it flying. I am using his base tune and trying to tune the tricopter for my setup. However, I am experiencing a problem that I have never experienced before. Maybe it's something simple, but I am not sure where to look.

The tricopter is flying relatively nice, but it's doing this strange rhythmic pulsing of the motor, where all 3 motors (it sounds like) pulse and it jumps a few inches up and then it turns down the motors and falls back down by a few inches. Like a side to side oscillation you would get with too high of a P or I value, but a vertical oscillation.

It's as if I was to constantly jerk the throttle up and down. I played around with the PIDs, but it doesn't seam to change anything regarding the vertical oscillation. The problem was really pronounced when I had motor brake on. With motor brake off it is flyable, but I can still hear the motors constantly throttling up and down. It's a pretty rhythmic pulsing, about twice a second or so.

I checked the radio channels, and everything look ok, no strange glitches. Is it vibration from the motors? Something else?

Give me an idea of where to look, because I am kind of lost.

Thank you,

- Bogdan
 

jhitesma

Some guy in the desert
Mentor
There must be a Naze tricopter curse on the southwest :D

What ESC's are you using? Does it happen in bench testing? If so can you see the motor outputs pulsing? Could you tie it down and throttle it up and see if it happens where you can monitor the motor outputs to see if it's the signals to the ESC or the ESC's causing it?

Of course given my luck with my V3 and Naze I'm probably not a good person to be helping trouble shoot right now :D
 

x0054

Senior Member
I am using the RCTimer 30AMP OPTO ESCs flashed with latest SimonK. I suppose I can reflash them with BLHeli and see if that changes things. To be honest, I have been having issues with those ESCs at first, because they needed the ground reference wire, and I didn't attach one at first. But after attaching ground reference I ran a bunch of bench tests with props on and off, and didn't have any sync issues at all. I ran some tests by attaching an RC RX directly to the ESCs, and encountered no problems with sync.

Next I am going to try to take the props off and try to "fly" the tri on my desk and see what it does on the outputs, like you recommended. I'll report what happens.
 

x0054

Senior Member
Well, it looks like the culprit for my problems is motor vibration. I balanced the props as best as I can, but it looks like the motors them selves are vibrating and causing this problem. I am not 100% sure about this, but when I turned down gyro_lpf from 42 to 10, the problem mostly stopped. Of course with gyro lpf set to 10, the tricopter is flying really sluggishly and has a tendency to get really destabilized by the wind, so it's not a solution, but it's at least an indication to what the problem might be.

I am not sure how to balance the motors, and I am not sure even if it's the motor, or the prop adopter that's causing the vibration. Other then that, even with the strange pulsing up and down, the tricopter is flying great. So it looks like the PIDs are ok, but the vibration is screwing things up.
 

x0054

Senior Member
Well, I just confirmed it, it's the vibrations. I mounted an AfroNaze on 4 layers of foam tape and connected everything to the AfroNaze. No more motor oscillations. It needs some tuning for sure, the PIDs are off a bit, but it's flying well overall.
 

Ludodg

Member
Bind a ziptie around the motor, cut the excess off. As the ziptie has a heavier head on one side of the motor, you can use this "head" or "lock" as a bery small weight.
spin the motors and check if the engine is in balance=no more oscillations. If not, turn the ziptie a notch and keep checking untill balanced.

I learned this method from one of the FT-shows!
 

x0054

Senior Member
Ah, thanks. I'll try that. I think one of the problems with these motors is the collet prop adopter. It looks like these motors also take the bolton prop adopter as well, maybe switching to that would improve things. Not sure where to get those though.

I made a little video of what it's doing. (https://youtu.be/VXebcz7P_PQ) You can't really see the oscillations because they are very quick, and it's hard to capture on video. But you can hear the buzz-buzz-buzz noise. That's the motors pulsing. This is with motor brake off. With motor brake on it's really pronounced.

- Bogdan
 

Ocean

Member
Ah, thanks. I'll try that. I think one of the problems with these motors is the collet prop adopter. It looks like these motors also take the bolton prop adopter as well, maybe switching to that would improve things. Not sure where to get those though.

I made a little video of what it's doing. (https://youtu.be/VXebcz7P_PQ) You can't really see the oscillations because they are very quick, and it's hard to capture on video. But you can hear the buzz-buzz-buzz noise. That's the motors pulsing. This is with motor brake off. With motor brake on it's really pronounced.

- Bogdan

Cheap Collets are notorious for the vibrations they cause.