Hexa roll wobble problem

[martinito]

Hi all

I'm building my third (multiwii) multicopter, and this one is my first hexa.
This time I chose to opt for an already built hexa frame (to reduce frame/weight ratio), the ATG 600-X6 frame.
I already had four A2212 1000kv and 4 hobywing skywalker 20A ESCs so I purchased an extra set of 4 in order to have 2 spares (they do not come from the same batch).
I'm using 1045 propelles.

I calibrated all ESCs and configured the quad as follows:

• Front left: old motor, old ESC
• Front right: old motor, old ESC
• Left: new motor, new ESC
• Right: new motor, new ESC
• rear left: new motor, old ESC
• rear right: new motor, old ESC

With that configuration, whatever PID i set for roll, I get a terrible wobble and keep crashing.

the old components worked perfectly on my previous Quad X, the minthrottle is correctly set and since the elements positionned symetrically ... I'm completely lost!


Does anyone have any idea of how to solve this?

Thanks,
Martin

[tovrin]

are you certain your motors are positioned correctly? I recently disassembled my quad and when i put it back together i accidentally swapped 2 motor wires to my pairs board. my quad would take off straight up then wobble then flip over.

[martinito]

Hi tovrin,
they all spin in the right direction & propellers are correct.
My issue is only on the roll axis.

[tovrin]

im sure your setup is correct, but by your reply i assume you misunderstand me. my motors spun correctly too, my props also setup right, i had flip flopped opposite motors on the board side, aka, i plugged motor 9 into slot 3 on my paris board, and 3 into 9 (not exactly, but for description purposes).

once i fixed my mistake my quad flew properly.

[martinito]

Hi torvin, thanks for your help
Just checked, and all connections to the multiwii are correct.
Do you think swapping ESCs and motors could help?

Thanks,
Martin

[tovrin]

Im always a fan swapped things around as a troubleshooting method, so why not.

[martinito]

Managed to stabilise it somehow. I'm not sure I found the root cause but here is what I did and the hexa is now flyable:
- swapped motors with no visible impact
- I had two ESCs still configured with the brake on
- recalibrated two ESCs
- I had lost a couple of screws, I put new ones (reducing vibrations)
- I changed the "I" parameter for the roll axis from 0.030 to 0.060

The copter still wobbles on the roll axis but it is flyable at least now. I'm going to try tweaking the PID parameters a little more.
Any other ideas?

[tovrin]

yea, frame tightness cost me a lot of aggravation too

[whit101]

Managed to stabilise it somehow. I'm not sure I found the root cause but here is what I did and the hexa is now flyable:
- swapped motors with no visible impact
- I had two ESCs still configured with the brake on
- recalibrated two ESCs
- I had lost a couple of screws, I put new ones (reducing vibrations)
- I changed the "I" parameter for the roll axis from 0.030 to 0.060

The copter still wobbles on the roll axis but it is flyable at least now. I'm going to try tweaking the PID parameters a little more.
Any other ideas?

I'm having a related? problem. Without warning it seems, the quad(HT-FPV) will begin to roll left/right rapidly back and forth until flips inverted and crashes. I just finished the aircraft 2 days ago. I've flown the quad 8-9 times, total time 30min. I have been flying another quad for a month. Don't believe it is PIO(Pilot Induced Oscillation), it is too rapid. I don't know enough about the Quadrino to make intelligent adjustments and it happens with ACC+Baro+Mag On or Off. Help...THX